Front Cover
 Title Page
 Table of Contents
 Newconservation tillage technologies...
 Advances in mulch-based conservation...
 New bread wheats for high rainfall...
 Breeding wheat for marginal...
 Increasing durum wheat yield potential...
 A new approach to triticale...
 Adaptation of winter wheat to Central...
 Farmer participatory variety selection...
 Global monitoring of wheat rusts,...
 Marker-assisted selection for BYDV...
 Durable resistance to yellow (stripe)...
 Applying physiological strategies...
 CIMMYT wheat research and capacity...
 Chinese wheat production in the...
 Improving wheat production in Central...
 CIMMYT's advances wheat improvement...
 Publications by wheat program staff,...


Research highlights of the CIMMYT Wheat Program
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00077530/00001
 Material Information
Title: Research highlights of the CIMMYT Wheat Program
Alternate title: Research highlights of the Centro International de Mejoramiento de Maíz y Trigo Wheat Program
Physical Description: v. : ill. ; 30 cm.
Language: English
Creator: CIMMYT Wheat Program
Publisher: International Maize and Wheat Improvement Center
Place of Publication: Mexico D.F
Creation Date: 1999
Publication Date: 2000-
Frequency: biennial
Subjects / Keywords: Wheat -- Periodicals -- Developing countries   ( lcsh )
Genre: serial   ( sobekcm )
Dates or Sequential Designation: 1999-2000-
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 48126989
lccn - 2001220385
System ID: UF00077530:00001


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Table of Contents
    Front Cover
        Front cover
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
        Page iv
        Page v
    Newconservation tillage technologies for surface-irrigated production systems
        Page 1
        Page 2
        Page 3
        Page 4
    Advances in mulch-based conservation agriculture
        Page 5
        Page 6
        Page 7
    New bread wheats for high rainfall environments : The package
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Breeding wheat for marginal environments
        Page 13
        Page 14
        Page 15
        Page 16
    Increasing durum wheat yield potential and yield stability
        Page 17
        Page 18
        Page 19
        Page 20
    A new approach to triticale improvement
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
    Adaptation of winter wheat to Central and West Asia
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
    Farmer participatory variety selection in South Asia
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
    Global monitoring of wheat rusts, and assessment of genetic diversity and vulnerability of popular cultivars
        Page 38
        Page 39
        Page 40
    Marker-assisted selection for BYDV resistance in wheat
        Page 41
        Page 42
        Page 43
        Page 44
    Durable resistance to yellow (stripe) ruse in wheat
        Page 45
        Page 46
        Page 47
        Page 48
    Applying physiological strategies to wheat breeding
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
    CIMMYT wheat research and capacity building in Eastern, Central, and Southern Africa
        Page 57
        Page 58
        Page 59
        Page 60
    Chinese wheat production in the CIMMYT-China partnership
        Page 61
        Page 62
        Page 63
        Page 64
    Improving wheat production in Central Asia and the Caucasus
        Page 65
        Page 66
        Page 67
        Page 68
    CIMMYT's advances wheat improvement course : opening doors to NARS senior scientists
        Page 69
        Page 70
        Page 71
        Page 72
    Publications by wheat program staff, 1999-2000
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
Full Text



Research Highlights
of the
CIMMYT Wheat Program



CIMMYT (www.cimmyt.org) is an internationally funded, nonprofit, scientific research and training
organization. Headquartered in Mexico, CIMMYT works with agricultural research institutions worldwide
to improve the productivity, profitability, and sustainability of maize and wheat systems for poor farmers in
developing countries. It is one of 16 food and environmental organizations known as the Future Harvest
Centers. Located around the world, the Future Harvest Centers conduct research in partnership with
farmers, scientists, and policymakers to help alleviate poverty and increase food security while protecting
natural resources. The centers are supported by the Consultative Group on International Agricultural
Research (CGIAR) (www.cgiar.org), whose members include nearly 60 countries, private foundations, and
regional and international organizations. Financial support for CIMMYT's research agenda also comes from
many other sources, including foundations, development banks, and public and private agencies.

F U T U R E Future Harvest builds awareness and support for food and environmental research
HAR E T for a world with less poverty, a healthier human family, well-nourished children, and
H R E S T a better environment. It supports research, promotes partnerships, and sponsors
projects that bring the results of research to rural communities, farmers, and families in Africa, Asia, and
Latin America (www.futureharvest.org).

International Maize and Wheat Improvement Center (CIMMYT) 2001. All rights reserved. The opinions
expressed in this publication are the sole responsibility of the authors. The designations employed in the
presentation of materials in this publication do not imply the expression of any opinion whatsoever on the
part of CIMMYT or its contributory organizations concerning the legal status of any country, territory, city,
or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. CIMMYT
encourages fair use of this material. Proper citation is requested.

Correct citation: CIMMYT. 2001. Research Highlights of the CIMMYT Wheat Program, 1999-2000. Mexico, D.F.

AGROVOC Descriptors: Maize; Wheats; Research institutions; On farm research; Research projects;
Research institutions; Agronomists; Starvation; Food resources; Agricultural resources; Plant breeding;
Triticum; Rusts; Mulches; Hard wheat; Farmers; Conservation tillage; Latin America; Africa; Asia.

AGRIS Category Codes: F30 Plant Genetics and Breeding

E10 Agricultural Economics and Policies

Dewey Decimal Classif.: 633.11

ISBN: 970-648-069-2

Printed in Mexico.

Table of Contents

New Conservation Tillage Technologies for Surface-Irrigated
Produ action System s- K .D Sayre .......................................................................................................... 1

Advances in Mulch-based Conservation Agriculture-P.C. Wall ................................................................. 5

New Bread Wheats for High Rainfall Environments: The Package-
M van G inkel and L G ilchrist ................................................................................ .......................... 8

Breeding Wheat for Marginal Environments--R.M. Trethowan ............................................................ 13

Increasing Durum Wheat Yield Potential and Yield Stability-
W .H 't ,tn K .D Sayre, and T.S. Payne ................... ...................................................................... 17

A New Approach to Triticale Improvem ent- A.R. Hede .......................................... .......................... 21

Adaptation of Winter Wheat to Central and West Asia-
H.-J. Braun, M. Mergoum, A. Morgounov, and J. Nicol .................... ..........................27

Farmer Participatory Variety Selection in South Asia-G. Ortiz-Ferrara, M.R. Bhatta, T. Pokharel,
A. Mudwari, D.B. Thapa, A.K. Joshi, R. Chand, D. Muhammad, E. Duveiller, and S. Rajaram........ 33

Global Monitoring of Wheat Rusts, and Assessment of Genetic Diversity and
Vulnerability of Popular Cultivars-R.P. :; ',i and J. Huerta-Espino......................................... 38

Marker-Assisted Selection for BYDV Resistance in Wheat-
M H enry, M van Ginkel, and M Khairallah ....................................... ............................................ 41

Durable Resistance to Yellow (Stripe) Rust in Wheat-
R.P. :;, ,i S. Rajaram, J. Huerta-Espino, and M William ................................. ..... .............. 45

Applying Physiological Strategies to Wheat Breeding-M.P. Reynolds, B. Skovmand,
R.M Trethowan, R.P. :;,i and M van Ginkel ........................................ ............................ 49

CIMMYT Wheat Research and Capacity Building in Eastern, Central,
and Southern Africa- D.G. Tanner and T.S. Payne ........................................ ......................... 57

Chinese Wheat Production and the CIMMYT-China Partnership-He Zhonghu ............................... 61

Improving Wheat Production in Central Asia and the Caucasus-
A. M orgounov, M Karabayev, D. Bedoshvili, and H.-J. Braun........................................... ................65

CIMMYT's Advanced Wheat Improvement Course: Opening Doors to
N A RS Senior Scientists- R .L. Villareal .......................................... ................................................ 69

Publications by CIMMYT Wheat Program Staff, 1999-2000 .......................... ......................... 73

CIMMYT-Derived Bread Wheat, Durum Wheat, Triticale, and
Barley Varieties Released in 1999-2000 .......................................................... ...................... 81

This volume presents the latest results from a global research program that continues to
be one of the most successful of all time. Throughout the developing world, food prices
are lower and malnutrition has declined, partly because of the strong research
commitment that is reflected in these pages. That commitment remains strong, because
the need for wheat research remains great.

In developing countries, demand for wheat will rise by 1.58% per year over the coming
two decades, faster than projected growth in demand for rice. By 2020 developing
countries will consume 67% of the world's wheat, and wheat will constitute more than
50% of the developing world's net cereal imports. More people will need more locally
produced food. At the same time, the agricultural resource base must be strengthened
and protected, cropping strategies must be developed to accommodate the potential
effects of climate change, and rural communities as well as research organizations must
be empowered to meet the challenges of a global economy.

This is no small task, even for a proven research program that is known to be effective
from the global level to the fields of individual farmers. The pages that follow indicate
the breadth of scientific inquiry that makes the CIMMYT Wheat Program so
tremendously responsive to the global, regional, and local needs of partners and those it
seeks to help. The reader will find research directed at wheats of different types and
growth habits; at the special regional needs of Africa, Central Asia, South Asia, and
Latin America; at favored, marginal, and high rainfall environments; at applications of
wheat physiology research for breeding strategies; at tillage and mulching practices for
a range of needs; at reinforcing disease resistance through molecular and conventional
breeding-and this is only a partial list of the contents of this volume!

These Highlights demonstrate the power of agricultural research to help the world's
marginalized people. The CIMMYT Wheat Program is to be congratulated on this
summary of its recent advances and on the scientific leadership and partnerships that
have made them possible. In this regard it has been the breadth and richness of our
partnerships that have been the cornerstone of global success, and we honor all of our
colleagues around the world through these Highlights.

Timothy G. Reeves

Director General, CIMMYT

We are pleased to initiate this series of publications highlighting research
undertaken by the CIMMYT Wheat Program. The purpose of the series is to
provide a brief but encompassing look at the Program and to enrich
CIMMYT's institutional memory. Since research does not necessarily yield
reportable results every year, these highlights will be published every other

The Wheat Program harks back to a research initiative that started in the
1940s, before CIMMYT was founded. The key to its continued success over
nearly 60 years has been to remain open to change and adapt to new
situations. Although it has evolved continuously in terms of its priorities
and methodologies, and the clients it serves, through it all, the Program has
been true to its core mission: to help wheat farmers in the developing world
produce more on less land while protecting natural resources.

The scope of the Program is both global and regional. Our plant breeding
programs have achieved global coverage, and we deliver our research
products through a network of programs in each region where we work. We
could not fulfill our mission without the collaboration of national
agriculture research systems throughout the developing world. Through its
outreach staff, the Program is present in each of the major regions where
wheat is produced: West Asia/North Africa, Central, Eastern, and Southern
Africa, South Asia, China, the Andean Region and Southern Cone of South
America, and the republics of Central Asia and the Caucasus.

To flesh out the record of activities with more definitive results, we have
included a list of publications (book chapters, journal articles, presentations,
and abstracts) produced by Wheat Program staff and the roster of CIMMYT-
derived varieties released in countries all over the globe in 1999-2000. These
products are a direct reflection of the success of our Program, and we are
proud to display them.

We hope this document will prove valuable both within and outside of
CIMMYT, today and in the future.

Sanjaya Rajaram
Director, CIMMYT Wheat Program

New Conservation Tillage Technologies for

Surface-Irrigated Production Systems

K.D. Sayre

Conservation tillage technologies, especially those
characterized by zero or very minimum tillage
with crop residue retention, have been largely
restricted to rainfed production systems, larger-
scale farmers, and developed countries.1
Furthermore, adoption of conservation tillage in
irrigated production systems has been extremely
limited in both developed and developing
countries, except for some small areas where
sprinkle irrigation is used.

Vast gravity- or surface-irrigated areas account for
well over 50% of wheat area and production in the
developing world (China, India, Pakistan,
Bangladesh, the Central Asian Republics, Turkey,
Egypt, Sudan, Nigeria, and Mexico, among others).
However, there had been essentially no
development of appropriate reduced or zero-tillage
technologies that could be easily implemented by
farmers, large or small, in those areas until the
recent advances made by CIMMYT agronomists in
collaboration with their national agricultural
research program colleagues. These advances have
occurred mainly in the irrigated rice-wheat systems
of South Asia and in the irrigated wheat-maize or
soybean system of northwestern Mexico.

Zero-Till Planting of Wheat after Rice
under Irrigation in South Asia
In Pakistan in the early 1980s, Dr. Peter Hobbs
(CIMMYT wheat agronomist then but currently
with CIMMYT's Natural Resources Group) began
investigating the possibility of planting wheat after
flooded, paddy rice using zero-tillage seeding
practices. This approach provided opportunities to

reduce production costs and minimize-or even
reverse-the long-term, detrimental effects on
production sustainability of the considerable tillage
being used. However, the major immediate
advantage to farmers was the dramatic reduction
in crop turn-around time (harvest today, plant
tomorrow) that zero-till offered compared to
conventional tillage. The period normally needed
for land preparation after the rice harvest before
planting wheat was sometimes as long as three
weeks. Since wheat yields can be reduced by up to
50 kg/ha/day for each day past the optimum
planting date, timely wheat planting provides an
immediate benefit to farmers.

Since there was no zero-till planter available that
was appropriate to the predominantly small-scale
Pakistani farmers, Hobbs and his colleagues
initially modified a small, zero-till planter
imported from New Zealand; it was appropriate in
size, but too costly to import and sell commercially
in South Asia. The modified, imported planters
were used to conduct numerous research trials in
farmers' fields in many Pakistani locations over
several years. These trials quickly demonstrated
the multiple advantages of zero-till wheat planting.

A local machine company began to manufacture a
reasonably priced zero-till planter based on the
modified planter. However, largely because of
skeptics unfamiliar with the technology, nothing
happened for another 15 years.

A similar situation occurred in northwest India.
Agricultural engineers at Pantanagar University
were able to modify the existing "rabi" wheat drill
using the same "inverted T" openers introduced by

1 The exceptions are Brazil and Argentina, where tremendous progress in adoption of zero-tillage has occurred.


Hobbs on the zero-till planters from New Zealand.
The modified planter worked well and was
remarkably low priced. But largely due to
researcher/ leadership skepticism, nothing
happened for several years, as occurred in Pakistan.

Several factors were essential for effecting change in
both countries, but perhaps most important were
two dynamic NARS scientists, Dr. R.K. Malik, weed
scientist at HAU in Haryana, India, and Dr. Mustaq
Gill, director of the on-farm water management
program in the Punjab, Pakistan. Both shared
Hobbs' conviction that new, more efficient,
economical, and sustainable technologies were
needed for the rice-wheat system. They viewed
zero-till wheat planting and direct farmer
participation as fundamental to developing relevant
technologies and getting them out to farmers
quickly. They both developed the approach of
placing zero till planters in the villages with
motivated staff to work with farmers.

The similarity of what occurred in both cases is
striking. From a total of about 20 ha planted in a
number of farmers' fields two or three years ago,
each program planted nearly 6,400 ha of zero-till
wheat during the 1999/00 crop cycle. Tremendous
farmer demand exists for zero-till planters in both
countries, and manufacturers are striving to meet
demand. At least 500 planters will be sold in
Pakistan this year.

Many farmers now realize that zero-till wheat after
paddy rice is a new, integral part of normal
production technology for the irrigated paddy rice-
wheat cropping system. In addition to higher, more
stable yields from more timely wheat planting,
farmers are saving about 98 liters of diesel fuel per
hectare by reducing the number of tillage passes
(up to 10) normally used to plant wheat after
flooded paddy rice. Irrigation water savings
average nearly 20%, and many annual weeds such
as Phalaris minor appear to be less prolific under
zero-till. The potential effects of this technology are
revolutionary, for it offers real progress towards
making farmers' production systems more
sustainable, input efficient, and profitable.

The events in the province of Punjab in Pakistan
and the state of Haryana in India constitute a clear
lesson on how to more efficiently introduce new,
relevant technologies to small-scale farmers. The
technologies need to address real problems and
must be tested and understood by the people who
will be directly involved with farmers. Researchers
should strive for direct farmer participation as early
as feasible, i.e., even during the development stage
of the technology. Furthermore, when major
changes are being made in farmer practices such as
converting to zero-till planting, appropriate
machinery and equipment, new or modified, will
be needed. Someone needs to make sure that the
proper prototypes are developed and that some
entity will be able to build adequate numbers of
good quality machines.

Irrigated Bed Planting Systems in
Northwest Mexico
Irrigating crops through furrows or corrugations is
not a new technology. It is practiced in parts of West
Asia (Turkey and Iran), in Pakistan and China, and
is one of the more common irrigation systems in
western USA. This irrigation system is more
commonly used for row crops such as maize,
cotton, dry beans, and soybeans but is also used for
small grains such as wheat. Small grains are
generally planted on the flat with the irrigation
furrows 70-100 cm apart.

Far more common (especially among small farmers
in South Asia and China) is irrigated wheat planted
on the flat with flood irrigation, though the same
farmers may grow other crops with furrow
irrigation. Almost all surface-irrigated systems
combine heavy tillage with crop residue
incorporation (maybe the minority) or crop residue
removal, often by burning (probably the majority).
Flood irrigation for wheat is practiced on
essentially all the irrigated rice-wheat area (about
25 million ha). However, there is at least that much
area or more under surface irrigated production
systems where wheat is grown in rotation with
other crops besides rice.

Given these circumstances, the changes that have
occurred in farmers' production practices over the
past 25 years in northwest Mexico, especially in the
Yaqui Valley of Sonora, have given scientists and
farmers the opportunity to develop more
sustainable irrigated production systems. This is
also an example of farmers taking the lead in
modifying production practices, well ahead of most
researchers and machinery manufacturers.

Twenty-five to thirty years ago, nearly all farmers
in the Yaqui Valley planted their wheat on the flat
and used flood irrigation. The wheat production
system was characterized by extensive tillage and
crop residue burning and by heavy dependence on
herbicides to control weeds. Today more than 95%
of farmers plant their wheat on beds and use
furrow irrigation (70-100 cm between furrows). The
major innovation that farmers introduced was to
plant on top of each bed 2-3 defined rows, spaced
15-40 cm apart, depending on bed width and row
number. This simple modification offered new
wheat management options that allowed farmers to
dramatically improve production efficiency and
reduce production costs. By simply changing to
furrow irrigation, they realized an average savings
of 25% in irrigation water. By planting 2 or 3
defined rows on top of each bed, farmers were able
to gain new advantages for wheat by utilizing
management practices such as:

* Pre-seeding irrigation, which allowed the weed
population to be controlled mechanically at
planting and enhanced crop establishment,
especially in heavy, crust-forming soils.
* Mechanical weeding in the furrows and between
the rows after crop emergence; this, combined with
pre-seeding irrigation, has reduced herbicide use
from 71 r, of farmers 25 years ago to less than
1iIr at present.
* Band application of fertilizers in the bed at
planting, followed by banding of side-dress
nitrogen at critical times after crop emergence
(instead of the more inefficient N broadcast
application or application in the irrigation water),
which can dramatically improve N use efficiency
and enhance grain quality.
* Decreasing intra-plant competition and using lower
seed rates, which reduces crop lodging.

The clear advantages of planting wheat on beds
made it likely to be useful in other similar areas,
especially where irrigated wheat is grown in
rotation with other upland crops or with rice. Basic
to its dissemination was a training program
initiated in 1994 to bring visiting scientists to
CIMMYT-Mexico. During the wheat crop cycle in
Ciudad Obregon (located in the Yaqui Valley),
these scientists study the bed planting system so
they can later test its utility in their home areas.
Since 1994, over 39 agronomists, mainly from Asia,
but also from Africa and Latin America, have been
trained in bed planting. Research, development,
and extension programs for bed planting are
currently underway in India, Pakistan, China, Iran,
Turkey, Sudan, and several Central Asian republics.
In most cases, similar improvements in production
efficiency are being obtained, including irrigation
water savings of 25-50%. Although the lack of
adequate bed planting machinery has been a
common constraint, each country is working on
developing appropriate machines.

In the summer of 2000, trials were initiated in India
to investigate the feasibility of growing rice on
beds in rotation with wheat (R. Gupta, pers.
comm.). Some extremely favorable results were
obtained, including more than 50% savings in
irrigation water compared to transplanted puddled
rice. Grain yields were similar in both systems.

Nearly all farmers in the Yaqui Valley continue to
use fairly extensive tillage and considerable crop
residue burning. However, farmers using the bed
planting system have quickly realized that if the
same bed width is used for all crops in their
production system, they can reduce tillage by
reusing the same bed for succeeding crops.
Therefore, it is common practice to till, make new
beds, and plant wheat. After the wheat harvest, the
straw is removed for fodder or burned (most
common), and the same beds are then used to plant
soybean. After the soybean harvest, tillage is
performed again, before planting wheat or another

Burning is practiced due to a lack of planters that
can plant soybean into maize residue. Also, no
commercial planter is designed to plant 2-3 rows of
wheat on top of a bed into residue and without
tillage. However, with the bed system, a
dramatically reduced till, residue-managed wheat
production system for surface irrigated situations
could be developed.

In 1993, this author initiated research in the Yaqui
Valley to develop a permanent bed system for
irrigated wheat-maize and soybean rotation. Here
tillage is reduced to a simple reshaping of the beds
after harvesting one crop and before planting the
next. Residues are chopped and evenly distributed.
Much time and effort have gone into developing
appropriate machinery to reshape and plant on
permanent beds, and very sound prototypes have
been developed.

Trials comparing permanent beds and different
straw management regimes with conventional-till
beds have been conducted for eight years. Results
from these trials indicate that crops planted on
permanent beds are higher yielding (especially
when all residues are retained) than those sown

using the conventional farmers' practice, and that
the new technology reduces production costs by
nearly 25%. Therefore the technology is currently
being extended to farmers in northwest Mexico,
and scientists from other countries are being
trained to disseminate it to other similar areas.

Permanent beds provide the first real opportunity
to reduce tillage and retain residues, which leads to
marked improvements in soil physical, chemical,
and biological parameters and water use efficiency
(especially in hot weather) due to the mulch effect.
With permanent beds there is better field access to
band fertilizers when and where needed, allowing
fertilizers (especially N) to be managed more
efficiently. Permanent beds also provide a built-in
system to control traffic and reduce soil
compaction, since all machines circulate on the
bottom of the furrows, not on the bed top where
crops grow.

Given all its benefits and advantages, the
permanent bed planting system is in keeping with
CIMMYT's mandate to offer sound, productive,
sustainable cropping systems to developing world

Advances in Mulch-based

Conservation Agriculture

P.C. Wall

Over the past two decades there has been a
remarkable spread of a new type of agriculture
based on residue retention (mulch) and direct
seeding into this residue with little soil movement.
There are many names for this type of agriculture
(no-tillage, zero tillage, direct seeding, and,
occasionally, conservation tillage), all of which try
to convey the two basic requirements of the system:
residue cover and seeding into residue without soil
inversion and as little soil movement as possible.
Today there are over 50 million hectares under zero-
tillage in the world, up from only a few hundred
hectares at the beginning of the 1980s. This zero-
tillage revolution has required scientists and
farmers to rethink and redefine many conventional
theories and wisdom on crop and soil management.

The major benefits of residue retention and direct
seeding are increased water infiltration (usually
leading to higher water use efficiency), a reduction
in soil erosion, build-up of soil organic matter,
carbon sequestration, and improved soil chemical,
physical, and biological fertility. The major benefits
to the farmer are the reduction in soil erosion,
increased yields (especially in dry years), more
timely sowing, less use of manual labor, and large
reductions in machinery and fuel costs.

The major characteristic of successful no-tillage
systems is the maintenance of sufficient mulch on
the soil surface, for mulch is the motor behind the
chief benefits of the system. As some pathogens that
cause crop diseases are able to survive on the
residues, crop rotation becomes even more
important in no-tillage systems than it is in
conventionally tilled systems. In designing crop
rotations, balancing residue production with
economic production is important to maintain
sufficient soil cover for the system to work.

One of the major reasons for tilling the soil is for
weed control; in systems where the soil is not tilled,
controlling weeds becomes critical. Initially weeds
are controlled by desiccating herbicides prior to
seeding, and then with normal post-emergence
herbicides. With time, however, in well-managed
systems where weeds are not allowed to set seed,
weed populations are reduced as seed is no longer
incorporated into the soil, the soil seed bank
produced by previous conventional tillage is
reduced, and the mulch soil cover helps control the
weeds. However, good integrated weed control
remains a prerequisite for successful systems.

Dissemination of Zero-Tillage Agriculture
Mulch-based conservation agriculture has been
adapted to a wide variety of soil, topographical,
and climatic conditions. There are areas of no-tillage
agriculture from the equator to 500 north latitude
and nearly to 400 south. No-tillage is practiced on
soils ranging from heavy clays (80% clay fraction in
Brazil) to light sands, and on plains and hillsides.
The key to this wide adaptation has been the
understanding by farmers and scientists of the
principles of conservation agriculture and the
creative adaptation of equipment and farming
systems to overcome practical problems. However,
as yet, the system has not worked well in soils with
a severe drainage impediment, or where rainfall is
too low for annual cropping and residue production
is very low.

To date most of the expansion in zero-tillage area
has been on large mechanized farms in the USA
(19.75 million ha), Brazil (12 million ha), Argentina
(8 million ha), Canada (4.08 million ha), Australia
(8.64 million ha), Paraguay (0.8 million ha), Mexico

(0.64 million ha), and Bolivia (0.2 million ha) (data
from Derpsch, 20001). However, zero-tillage is
increasingly being adapted to small farmer
circumstances and adopted by small farmers; in
Brazil, Mexico, and Paraguay part of the area of
expansion is on small farms. There have also been
important levels of adoption on small farms in
Pakistan, and 100,000 small farmers in Ghana are in
the process of adopting this technology (J. Ekboir,
pers. comm.).

Major Benefits of Zero-Tillage
In surveys conducted in Brazil and Paraguay, small
farmers who have adopted zero-tillage indicated
that the main benefit they reaped from the change is
the savings in time and manual labor. This has
given them more leisure time, allowed them to
diversify into other enterprises, and reduced the
time children must spend working on the farm
(freeing them for more formal education).

A case study in Paraguay2 showed that average net
farm income of the five farms studied doubled (a
101.4% increase), and income for each person-day
worked increased by 127%, leading the consultant
who conducted the study to conclude that "no-till
and crop rotations constitute a technological
revolution for small farmers. Never before has the
senior author analysed such an impressive
technology for small farmers in more than twenty
years of extensive experience analysing small farm
systems in South America, Africa and Asia. To the
authors' knowledge, no other farming techniques
have been shown to have such a high impact on
farmers' incomes, reduce their production costs and
risks, and at the same time be environmentally
sustainable and generate very considerable net
social gains to society. To realise these private and
social benefits will be a major challenge that will
call for considerable effort and dedicated support."

Major Restrictions to Adoption
Apart from lack of knowledge of the zero-tillage
system, there have been, and still are, two major
limitations to zero-tillage adoption on small farms:
lack of adequate seeding equipment and other uses
of crop residues, principally for animal feed,
building, and fuel.

Seeding equipment for large grained crops such as
maize is not a major problem: the pointed stick or
"punzon" used by many farmers in Mexico and
Central America to make the hole for the seed is
well adapted to situations with residue cover and,
therefore, to zero tillage. This system of seeding is
centuries old, as evidenced by a 1549 report by
Bishop Diego de Landa that the Mayans in Yucatan,
Mexico, were using it. Unfortunately, weed control
was also a problem in this system, so prior to
seeding, all plant residues on the fields were
burned, leaving the soil surface bare. Today many
farmers in the same region sow a relay crop of
mucuna (a legume) in the maize, which covers the
area after the maize harvest. Before the next season
it is killed by frost or by a desiccant, and the
following maize crop is seeded into the residue.
This produces major benefits such as increased
fertility following the legume, increased water use
efficiency, and excellent weed control due to the
ground cover.

Zero-Till Seeding
Much of the zero-tillage seeding of maize and
beans on small farms in Brazil is carried out
manually with a modern version of the
"punzon,"or "matraca." This is a device with two
handles that is pushed into the soil; seed and
fertilizer are released by bringing together the

Row seeding of crops using machines adapted to
animal or human traction has, however, been more
problematic, since machines for zero-tillage need to

1 Derpsch, R. 2000. Expansion mundial de la siembra direct y avances tecnol6gicos. Trabajo presentado en el Curso de Siembra
Directa, PROCISUR, Cochabamba, Bolivia. 2 al 4 de Mayo del 2000.
2 Sorrenson, W.J., Duarte, C., and L6pez, P.J. 1998. Economics of no-till compared to conventional cultivation systems on small
farms in Paraguay. Policy and investment implications. Final Report of a Study for the Soil Conservation Project MAG-GTZ,
DIA/DEAG, Asunci6n, Paraguay. 228 pp.

be heavier and more rugged to cut through surface
residues and penetrate the soil to the required
seeding depth. Whereas surface soil in a
conventional system is loose and easy to penetrate
with a light machine, the surface layer in untilled
fields is denser and requires more force for

Successful machines for widely spaced crops such
as maize have been developed in several areas,
notably in Brazil. Traditionally these machines have
been heavy, a factor that is not normally a problem
while seeding, but their maneuverability at field
edges is difficult. A new generation of machines
relies more on fulcrum physics than on sheer
weight, and there are now lightweight seeders
available for seeding row crops.

With respect to seeding equipment, the biggest
problem remaining is how to sow small-seeded
crops such as wheat, barley, and many green
manure cover crops. Although single-row seeders
can often sow these crops, the time required for
seeding is high due to the closeness of the rows.
However, advances are being made, and workable
machines, although not perfect, are becoming
available in India, Pakistan, Ethiopia, and Bolivia
(and probably in other countries).

These machines typically seed three to five rows at
a time, and are supported on wheels, at least for
turning at the field margins. Weight continues to be
a problem as the force needed to cut through
residues with a 3-row seeder is three times higher
than with a single-row seeder. However, the time
saved by using these machines is important. In
Bolivia a farmer typically prepares his land twice
with a wooden plow before seeding, broadcasts the
seed, and then incorporates with another pass of
the plow. To plant one hectare, the farmer walks 100
km behind his oxen to prepare the land and cover
the seed, and another 2 km to sow it. In contrast, if
he direct-seeds a hectare with a 3-row seeder (25 cm
between rows), he will walk only a little over 13 km
and will achieve a far better plant stand with the
row-seeded crop than with the broadcast one.

Problems Yet to Be Solved
Alternative uses of crop residues remain a problem
in many areas. However, experience in Bolivia
shows that once farmers see the benefits of surface
residue retention in their fields, they are far more
willing to look for and adopt alternate feed
sources. These include sowing forage crops during
the normally fallow period and planting of live
contour barriers with forage species, which reduce
erosion and slowly form terraces. Increased grain
and straw yields attained with more efficient water
use also allow farmers to use part of the crop
residues for feed and still leave enough residues
for adequate ground cover on the field. However,
one major problem is that according to local
custom, grazing rights after harvest are communal,
which means that an individual farmer is not
allowed to maintain crop residues in his field;
rather, this is a community decision.

Another problem facing development agencies is
harvest methodology. Hand-harvesting small-grain
cereals and then threshing by trampling the crop
outside the field means most of the straw is
removed from the field. Returning the straw for
ground cover is expensive in terms of manpower,
and unattractive to farmers. On flat or gently
sloping land, machine harvesting is the preferred
method, as it is generally cheaper than hand-
harvesting, reduces the harvest-to-market interval,
results in a cleaner product, and leaves crop
residues on the field. However, development
efforts are required to make machine harvesting
more widely available and to promote small
custom-harvesting enterprises.

New Bread Wheats for High Rainfall

Environments: The Package

M. van Ginkel and L. Gilchrist

High rainfall environments make up the second
major mega-environment where bread wheat is
grown in the world, after irrigated production
areas. Particularly in developing countries, regions
receiving more than 500 mm of rainfall during the
cropping cycle suffer retarded economic
development and the associated curses of
unemployment, poverty, ill health, and high
infancy death rates. Such areas include parts of
Eastern, Central, and Southern Africa, the Andean
Region of South America, China, and pockets in
South Asia.

Enormous progress has been achieved in
disseminating so-called modern varieties in
irrigated regions around the world. Key wheat
ideotypes, such as the Veerys and, more recently,
the new wheats Kauz and Attila, have
demonstrated their wide adaptation and stable
performance across this irrigated agro-ecological
zone. Adoption of modern wheats has reached
almost 100% in high rainfall areas in the last
decade. However, few genotypes have shown to
contain the complete "package" of requirements for
that zone. The Bobwhites constituted an impressive
advance some 20 years ago, but with evolving
diseases and market demands, new varieties are
continuously needed. Usually varieties do well for
a certain period and then succumb to diseases, or
their quality characteristics remain poor, and local
mills import most of the wheat they require,
negatively impacting local wheat producers.

There are several reasons for production instability
in high rainfall areas. For example, more diseases
thrive under higher humidity conditions than in
irrigated or rainfed areas with low humidity, and
nutrient imbalances (both deficiencies and

toxicities) are more pronounced in regions where
leaching associated with high rainfall is prevalent.

In many of these areas, wheat has been imported in
large amounts, for a variety of reasons, including
famines, political mismanagement of food
resources, lack of support for agricultural research,
immigration/ emigration pressures, cost / benefit
considerations, and the high industrial quality of
imports. Imported wheats generally come from one
or more of the top four wheat exporters in the
world: USA, Canada, Argentina, and Australia.
Since these countries grow wheat mostly under
rainfed conditions and produce the low yields (1.5-
2.5 t/ha) associated with elevated protein levels,
imported wheat is generally of superior quality.

Traits for High Rainfall Wheats
If a nation in a high rainfall area aims to satisfy
some, most, or all of its domestic wheat needs, its
breeders must address an extensive list of traits.
Wheats targeted towards high rainfall areas should
have some or, ideally, all of the following key traits:

1. Yield
a. High*
b. Stable*
2. Disease resistance
a. Stripe rust*
b. Leaf rust*
c. Stem rust*
d. Septoria tritici*
e. Fusarium spp. (head scab)*
f. Barley yellow dwarf virus
g. Soil-borne pathogens
h. Tan spot
i. Powdery mildew

3. Abiotic stress tolerance
a. Sprouting*
b. Soil acidity
c. Nutrient imbalances*
d. Waterlogging
4. Industrial quality
a. Bread making*
b. Cookie quality
c. Noodle quality (for China and Southeast Asia)

Though not all these traits are usually present in the
same variety, the 10 marked by an asterisk (*) often
constitute the minimum requirement in a high
rainfall environment, compared to 5-7 key traits
needed in wheats targeted to irrigated
environments. Breeding wheats that meet these
requirements poses a difficult challenge-one that
requires concerted efforts to meet it. The difficulty
is compounded by the fact that many countries in
high rainfall areas have been investing less in wheat
research in recent years.

Breeding and Selecting High Rainfall
Breeding wheats possessing the set of traits
required in a given target environment is key to
getting local farmers to adopt them. To incorporate
the key groups of traits detailed above breeders
must apply different methodologies; each group
will therefore be discussed separately.

Traits contributing to high, stable yields across all
potential production conditions within the high
rainfall mega-environment are not unlike those
needed to produce top yields in less stressed
conditions under irrigation. Optimum input use
efficiencies should result in maximum output (grain
yield) per hectare. Hence in the hybridization
process of a breeding program targeting high
rainfall conditions, the highest yielding genotypes
under irrigated conditions should be exploited, i.e.,
yield genes governing internal physiological
processes should be transferred to potential high
rainfall wheats. These genes constitute the genetic
core of a variety and determine its ultimate yield

potential. In addition to the top irrigated wheats,
the best yielding high rainfall wheats are also
sources of genes for yield.

Table 1 lists some of the highest yielding wheats
tested under high rainfall conditions in Mexico, in
comparison to the check line Prinia.

In all three crosses listed in Table 1, top-yielding
irrigated wheats (Veery #9, Seri M82, and Tui) are
present as progenitors and presumably contributed
"yield genes." An example of an outstanding high
rainfall progenitor is Bobwhite, which in the past
two decades has proven to be high yielding and
stable in such areas around the world.

Disease resistance
Once the introgression of yield genes into a variety
has been secured, their potential must be protected
from diseases so that high yields will be
phenotypically expressed in farmers' fields.
Protective disease resistance genes should be
incorporated into the new wheat through the proper
choice of additional parents in the crossing process.

Horizontal resistance is pursued against diseases
known to have host-pathogen interactions of a
specific, race-type nature. Though these diseases are
restricted mostly to the rusts, some claim that
certain foliar blights also show interactive behavior.
Horizontal resistance is also known as adult-plant,
partial, or field resistance and, in the case of the
rusts, as slow-rusting resistance. This type of
resistance is achieved by accumulating several
genes, each with minor additive effects. Parents are
used in combinations that will yield progenies
carrying three or more minor resistance genes for
each of the relevant diseases. In the case of the rusts,

Table 1. High yielding lines compared to the check variety
Prinia, 2000 crop cycle, Toluca, Mexico.
Yield Prinia
Cross Selection history (t/ha) %
PFAU/BOW//VEE#9/ CMSS95YO2460S-0100Y-0200M- 10.87 143
3/DUCULA 19Y-010M-6Y-030M-2SJ-OY
PGO/SERI//BAU/ CMSS95Y02262S-0100Y-0200M- 10.73 141
3/DUCULA 1 Y-010M-10Y-030M-2SJ-OY
MILAN/TUI CMSS95Y02595S-0100Y-0200M- 10.36 131

CIMMYT scientists have published on 12 such
existing minor genes, but estimates are that many
such genes reside in CIMMYT and other
germplasm, just waiting to be accumulated. For
diseases that do not express large host-pathogen
interactions in farmers' fields (mostly foliar blights
and soil-borne diseases), major genes with strong
effects can be used.

Table 2 lists entries that showed outstanding
resistance to Septoria tritici during the past crop
cycle in the Mexican highlands, where there was a
particularly strong epidemic due to very conducive
environmental conditions.

The crosses confirm the assumption that more than
one of the parents contributed resistance genes to
these lines, resulting in pyramided resistance.
Likely contributions are from South American
sources (IAS58 within TINAMOU), French stocks

Table 2. Lines showing a high level of resistance to Septoria
tritici during the 2000 crop cycle, Toluca, Mexico.
Cross Selection history Septoria tritici 00-99*
TNMU/MILAN CMSS95YO2037S-0100Y-0200M- 11
PGO/SERI//BAU/ CMSS95YO2262S-0100Y-0200M- 11
3/DUCULA 2Y-010M-7Y-030M-3PZ-OY
NG8675/CBRD/ CMSS95YO2978S-0100Y-0200M- 11
/MILAN 17Y-010M-3Y-030M-OY
*00-99 is the widely adopted Double-Digit scale.

Table 3. Lines showing they carry accumulated, diverse genes
for Type II resistance (reduced spread of fungus through the
spike's rachis) to Fusarium head scab, 2000 crop cycle,
Toluca, Mexico.
Cross Selection history Type II (%)*
SHA3/CBRD CMSS92Y00595S-1SCM- 2.50**
HXL8088/DUCULA CMSS93Y02492S-2Y-010M- 2.59
(205)//BORL95 24M-OY-01 OSCM-OY-OY-OY 3.41
1AL-2AL-7Y-OM-3SJ-OY 3.70
KAUZ/TNMU CMSS93B01069S-54Y-01 M-
010Y-010M-8Y-OM-3PZ-OY 5.00
(moderately resistant check) 9.20
* Denotes % of spikelets affected per spike.
** This entry also allows only very low toxin levels.

(VS73.600 within MILAN), a CIMMYT cross
released as SARA in Guatemala (within DUCULA),
plus several Chinese wheats (NG8675 and
CHUANMAI 18 within CATBIRD). Also note that
SERI, a high yielding variety mostly for irrigated
environments, again transmits adaptation to this

Table 3 presents new lines in which the progenitors
of the crosses would suggest that several genes for
Fusarium head scab (FHS) resistance were
successfully accumulated; this is also indicated by
the disease response data (Type II resistance against
spread of the disease through the rachis). Research
is in progress to determine whether these genes are
indeed different from one another and from earlier
used genes.

These five examples illustrate several points:

* Germplasm from several regions of China may
contribute resistance to Fusarium head scab:
Sichuan (CHUANMAI 18 within CATBIRD),
Shanghai (SHA #3), and Heilongjiang (HXL8088).
* These Chinese lines may add distinct genes that can
be accumulated: SHA3/CBRD is more resistant than
either parent.
* Synthetic wheats (e.g., CROC 1/AE.SQUARROSA
(205)) do confer resistance. In this particular
synthetic the resistance derives from the Aegilops
squarrosa parent (205) since the durum parent
(CROC) is known to be highly susceptible to scab.
* South American wheats (IAS58 within TINAMOU,
and the CIMMYT cross released as SARA in
Guatemala) bestow resistance genes.
* The Mexican highland sites Patzcuaro (PZ) and
Sierra de Jalisco (SJ) assist in identifying resistant
materials, as confirmed by their presence in certain
selection histories: CMSS93Y02492S-2Y-010M-010Y-
010M-10Y-1M-OY-3SJ-0Y and CMSS93B01069S-54Y-
* Resistance to Fusarium head scab can be
successfully combined with materials that are
principally known for their high yields in irrigated
conditions (BORLAUG F 95 and KAUZ).
* Some of these lines also contain tolerance to acid
soils, as attested by the "-AL" notation in their
selection histories, which indicates that they were
subjected to laboratory hydroponic testing using

solutions with high aluminum levels
* Most FHS resistance sources noted also convey
maintenance of a low toxin level in the grain despite
fungal infection.
* The advanced wheats listed are also resistant to the
three common rusts plus Septoria tritici.
Abiotic stress tolerance
One of the key abiotic constraints to production in
high rainfall areas is the high amount of rain that falls
on the maturing wheat crop. Excess rain causes the
grain to start germinating before it is harvested, which
compromises end-use quality due to the undesirable
proteins produced during germination. High rainfall
wheats should possess sprouting tolerance to
counteract this problem. Intermediate levels of
sprouting tolerance are available, mostly in red-
grained wheats, but higher levels are being sought.
Table 4 lists both red- and white-grained wheat lines
combining excellent sprouting tolerance with
acceptable yield and industrial quality.

These lines were selected from a Mexico/Australia
shuttle breeding effort. In Mexico the planting date
was adjusted so that grain-filling would coincide with
peak seasonal rainfall in Toluca; this caused sprouting

Table 4. Red- and white-grained lines having high levels of
sprouting tolerance in combination with acceptable yield (relative
to the check variety Prinia) and end-use quality (loaf volume).
Yield Grain Loaf
Cross Selection history Prinia % color volume
TUI/CLMS N91.358-3WM-102AUS-5WM- 102 Red 1025
HAHN/PRL//CLMS/ N92.240-2WM-60AUS-2WM- 91 White 875
3/HAHN/PRL 010WM-010Y-010M-2Y-0Y
TUI//2*SUNCO/ N92.241-1WM-71AUS-6WM- 102 Red 900
SA1166/3/TUI 010WM-010Y-010M-9Y-0Y

Table 5. New lines showing high levels of industrial quality
during the 2000 crop cycle (MV-00), Toluca, Mexico.
Use W Flour
Cross Selection history type value P/L protein
MILAN/TUI CMSS95Y02595S-0100Y-0200M- la* 785 0.9 12.7
TNMU/MILAN CMSS95Y02037S-0100Y-0200M- la 660 0.7 12.8
MILAN//PSN CMSS95Y02329S-0100Y-0200M- la 536 0.8 12.9
/BOW 9Y-010M-9Y-030M-3PZ-OY
SUse-type la = ideal dough strength and extensibility with high protein levels.

in sensitive segregants. In Australia the
populations were exposed to artificial excess
moisture in a controlled environment, again
permitting identification of desired tolerant
genotypes. The sources of sprouting tolerance
were Columbus and Sunco/SA1166.

Industrial quality
Industrial quality must be a key consideration
when choosing parents. If the proper
complementary genes are not introduced during
hybridization, they cannot be expected to turn
up in the progeny. Once the proper genes have
been introduced, it has become increasingly
evident that not much needs to be done in regard
to selection for industrial quality until advanced
lines appear. Apparently these genes transmit
themselves well through segregating
populations, so that a sufficient number of high
quality lines will emerge in the F7.

Several lines showed very high levels of
industrial quality during the last Toluca crop
cycle (Table 5). The quality values of these lines
are in fact among the highest one could expect to
obtain (W values above 500) while maintaining
high protein levels.

The 446 most outstanding lines from the recent
ME2 yield trials have been entered into the most
recent issue (10th) of the international nursery
High Rainfall Wheat Screening Nursery (10th
HRWSN). The new entries express high yield as
well as resistance to stem, leaf, and stripe rusts,
and Septoria tricici, plus a certain level of
resistance to Fusarium head scab.

Of the 446 entries, 101 (23%) have so-called
group 1 quality (balanced, strong, extensible); 76
(17%) of these actually show la type quality
(balanced, strong, extensible, but with protein
levels above 12%), the highest bread making
quality level attainable. Such high quality wheat
is used mostly for blending purposes (i.e., to
correct inferior flour). An additional 67 entries
(15%) have group 2 quality, representing good
bread making quality.

Taken together these data indicate that 38% of the
10th HRWSN has good to excellent industrial end-
use quality. This represents a breakthrough in terms
of combining top yield and disease resistance with
high levels of industrial quality.

The Package
It is clear from the above data that the key traits
required in high rainfall environments are now
available in different genotypes. In fact, in several
cases yield, resistance, and quality values reveal an
accumulation of desired genes for the respective

The final step in the process of breeding wheats for
high rainfall environments remains to be taken and
will settle the issue of whether the various
complexes of accumulated genes can be combined
to produce genotypes that would individually
express all the key traits.

Recent data have indicated that this is indeed
possible. For example, a select sample of elite
genotypes grown in the Mexican highlands during
the past one or two crop cycles appear to combine
high yield with resistance to the rusts and Septoria
tritici, plus high levels of industrial quality (Table 6).

These entries have not yet been exhaustively
evaluated for FHS resistance under controlled
conditions using artificial inoculation, nor have they
been tested for sprouting tolerance, two of the 10
key traits indicated above. Their pedigrees
(combining resistant progenitors) and selection
histories (of lines selected in Patzcuaro or Sierra de
Jalisco, where scab levels tend to be very high)
suggest that they may well possess FHS resistance.

In fact a sister line of the first mentioned line,
TNMU/MUNIA, has already been confirmed to
have a high level of resistance to FHS.

The world depends on breeders to provide farmers
with commercially competitive crop varieties that
will contribute to the lofty and necessary goal of
attaining overall food security. But in practice
individual farmers do not consider such lofty goals;
instead they make simple though integrated
economic decisions that reflect their agronomic
production environment and direct relation to the
local commodity market. Thus for a farmer a
variety must yield well with a high level of
predictability, and have the quality that local grain
buyers demand. In response, breeders need to
construct complex genetic packages (varieties) that
satisfy farmers' "simple" requirements.

The traits that ensure a wheat variety will succeed
in high rainfall environments are many. In
particular these wheats face numerous diseases,
which means that the combined resistances needed
to protect them can only be obtained through
concerted research efforts and may be lost as
pathogens evolve. Breeders must also combat
climatic and environmental vagaries that impact
yield and quality.

Fortunately, as documented in this report, it is
nevertheless possible to develop genetic wheat
packages for high rainfall environments that rival
the best irrigated wheats in yield and that defend
themselves successfully against numerous diseases,
while producing grain of superior industrial quality.

Table 6. New lines combining high yield (relative to check variety Prinia) with high levels of Septoria tritici resistance and good
industrial quality characteristics, 2000 crop cycle (MV-00), Toluca, Mexico.
Yield Prinia Septoria Use- W P/L Flour
Cross Selection history (t/ha) % tritici 00-99 type* value** *** protein****
1NMU/MUNIA CMSS93B01052S-18Y-010M-010Y-010M-4Y-3M-0Y-1PZ-0Y 9.06 129 11 la 595 1.3 11.7
MILAN//PSN/BOW CMSS95Y02329S-0100Y-0200M-9Y-010M-9Y-030M-4SJ-OY 9.09 120 21 la 530 0.5 13.3
ALD/COC//URES/3/DUCULA CMSS95Y02455S-0100Y-0200M- 10Y-010M-4Y-030M-2PZ-OY 9.59 126 11 la 392 1.0 12.2

Use-type la = ideal quality wheat with strong, balanced, extensible dough.
** P/L ratio must be 0.6-1.0.

W value must be 300 or above.
** Flour protein must be near 12% or above.

Breeding Wheat for Marginal Environments

R.M. Trethowan

The Target Environments
The CIMMYT bread wheat program produces
germplasm adapted to a wide range of different
moisture stress conditions. The breeding work
focuses on the following environments, each
classified by the stage at which moisture stress
generally occurs:

* Post-anthesis stress. These areas are characterized by
adequate winter rainfall with moisture stress
prevalent during grainfilling; an estimated 6
million ha are found in developing countries.
North Africa and West Asia are representative
* Pre-anthesis stress. These environments suffer from
winter drought with generally favorable conditions
post-flowering. An estimated 3 million ha are
found in developing countries. The Southern Cone
of South America is typical of this type of stress.
* Severe terminal stress. Farmers in these areas
generally plant on stored soil moisture. Little or no
rainfall occurs post-planting. The monsoonal areas
of South Asia and the spring-wheat-growing lands
of Central Asia/Western Siberia are typical. More
than 20 million ha with this type of stress are found
in developing countries.

Selecting Materials for Crossing
The CIMMYT program targets crosses for all these
areas by utilizing the most widely grown cultivars
and elite breeding lines from collaborating national
programs. These materials are crossed to elite
CIMMYT lines with high yield potential, disease
resistance, and grain quality. Synthetic hexaploid
wheat, produced by crossing durum wheat with
Aegilops squarrosa, is heavily used in crosses and
provides new sources of variation for stress

adaptive traits. The resulting progeny are then
tested in the various regions via the deployment of
elite international yield and screening nurseries.
The information collected in the regions on these
materials is returned to CIMMYT and used by the
breeders to target the next round of crossing.
Scientists working in national programs either
release these lines directly, reselect them, or
recombine them with their own germplasm.

Managing Segregating Populations
At the base program in Mexico, segregating
material is selected under alternating conditions of
moisture stress and high rainfall with high disease
pressure. Drought stress is simulated at CIMMYT's
experiment research station near Cuidad Obregon,
northwestern Mexico (27N, 25 masl) using limited
irrigation. The heritability of selection under
drought stress from year to year ranges from 0.5 to
0.7. This high degree of repeatability sets Obregon
apart from most of the world's rainfed wheat-
growing areas. Variable rainfall from year to year
makes selection for genuine drought adaptation in
these areas extremely difficult, as heritability across
years is often close to zero under most rainfed
conditions. Each alternate generation is selected
under high rainfall and high disease pressure at
CIMMYT's Toluca research station (19N, 2600
masl) in the central Mexican highlands. This
shuttle allows breeders to develop drought
tolerant, input responsive germplasm with high
levels of disease resistance, which is essential for
maintaining yield and income stability for farmers
living in marginal areas.

Evaluating Advanced Materials Targeted
for International Distribution
Once advanced lines have been identified, they are
yield tested at Obregon under two contrasting
moisture regimes to identify the drought tolerant,
input responsive genotypes. Following three years
of yield and disease evaluation, the selected lines
enter the CIMMYT international nursery system in
one of the three following nurseries:

* SAWYT Semi Arid Wheat Yield Trial
* SAWSN Semi Arid Wheat Screening Nursery
* HLWSN High Latitude Wheat Screening Nursery
Data on the performance of these lines across the
target marginal areas are collected by regional
cooperators and returned to CIMMYT to aid the
selection of parents for the crossing program.

Progress to Date in Breeding for Marginal
Prior to the introduction of the SAWYT in the early
1990s, the national agricultural research programs
of most wheat growing developing countries
selected materials for their marginal areas from
CIMMYT's traditional irrigated nurseries with
significant success. A recent examination of the
performance of 20 years of the Elite Spring Wheat
Yield Trial (ESWYT) indicated that yield improved
across this period at close to 4% per year (Pingali,

All materials entering the ESWYT have been bred
and selected under optimally irrigated conditions.
However, results from the SAWYT indicate that
rates of progress can be improved through the
deployment of materials bred and targeted to
moisture stress conditions. In low yielding
environments (less than 2.5 t/ha), rates of progress,
expressed as yield advantage of the best five lines
over the local check cultivar, have increased from
12% in 1991 to 38% in 1997 (Figure 1). Similarly, the
yield advantage of these top ranking genotypes in
environments suffering intermediate levels of
stress (2.5-4.5 t/ha) has improved from 16% to 45%

over the same time period. The regression of yield
advance over time was significant for both low and
intermediate yielding environments (r2 = 0.62,
P<0.01 and r2 = 0.42 P<0.05, respectively).

Refining the Breeding Effort
for Marginal Areas
There is little doubt that significant progress was
made during the past 30 years in developing
cultivars suitable to marginal areas. However, the
question is: can we improve upon or maintain
these rates of progress? This is of vital importance,
as many analysts believe improved production in
marginal areas is key to food security in the coming
decades (P. Pingali, pers. comm.).

The CIMMYT bread, durum, and triticale breeding
programs have not been idle in this respect.
Experiments have been conducted to evaluate
current breeding and evaluation strategies in an
attempt to fine-tune the already highly successful
breeding effort. An examination of the relationship
between the severe terminal stress generated in
Obregon and global marginal areas using data
generated by the SAWYT indicated that key target
areas in South Asia correlated well with Obregon.
Although high yielding, adapted germplasm could

Mean of the top 5 entries
as % of the local check
O Less than 2.5 t/ha
6 2.5-4.5 t/ha
140 __
140 --------------------- ------------
io-n ~ ~ ~ ~ r 062-- -- -- -

---- -------------------------------
110 ---------------------
---------------- ---------------------------


90 92 94 96 98

Figure 1. Trends in yield over time in low and intermediate
yielding environments.

be selected from either the SAWYT or SAWSN in
nearly every environment, not all environments
differentiated germplasm in the same way as
Obregon. Results indicated that a small adjustment
to the timing of drought stress in Obregon could
improve the correlated ranking of Obregon with
some environments, particularly in the Southern
Cone of South America. Combining what we know
of global wheat environments on the basis of yield
performance with GIS and other environmental
variables will help to improve definition of the
marginal areas and better target germplasm to
CIMMYT's regional cooperators.

Advances in molecular biology are expected to
provide exciting opportunities to improve the
efficiency of wheat breeding for marginal areas.
Functional genomics in particular may provide the
knowledge needed to enhance parental selection
and identify gene clusters important in conferring
adaptation to stress. Genomics will likely be a more
powerful tool than QTL analysis, as drought
tolerance is likely to be controlled by many
hundreds, possibly thousands, of gene loci. To
complicate matters, these loci "clouds" will change
with the environment. As a minimum, DNA
fingerprinting of key parental stocks will allow
breeders to better design crosses and calculate
coefficients of parentage more realistically.

Understanding the Target Environment
The adaptation of germplasm to marginal areas
involves much more than just drought tolerance.
For one thing, root health often determines a
plant's ability to perform well under drought. Root
growth can be influenced by a number of biotic
and abiotic factors including nematodes, root rots,

and micro-nutrient toxicities and deficiencies
(Table 1). Many of these traits are simply inherited
and can be manipulated to improve general
adaptation to marginal areas. Bioassays for root
diseases are difficult to manage and escapes are
frequent; therefore, molecular markers (if available)
offer significant advantages. The CIMMYT Wheat
Program routinely uses a PCR assay to determine
nematode resistance, and more markers are
undergoing validation.

We know that significant genotype x location
interaction occurs from the deployment of SAWYT
and ESWYT across many environments, yet we do
not understand why certain genotypes perform
well in one environment and collapse in another.
Deployment of a probe set of genotypes,
differentiating for the key soil-borne stresses, is
planned over the next few years. It is hoped that
this trial will shed some light on the major
limitations to the adaptation of wheat in many key
marginal areas. This knowledge will help breeders
at CIMMYT target germplasm to regions. For
example, some areas may be prone to root lesion
nematode, and more appropriate advanced lines
and parental materials could be provided to our
partners there. Knowledge of such constraints is a
powerful tool in our efforts to achieve increased
food production in the coming decades.

As farmers become conscious of the need to
conserve soil moisture and reduce erosion (Table
1), farming practices are changing in many wheat
growing areas. Wheat breeding programs must be
proactive in promoting changes in their selection
and evaluation strategies to reflect the changing
environment. If research suggests that no genotype
x tillage practice interaction exist in a given region,

Table 1. Factors affecting yield in dry environments.
Patterns of Nutrient stress and Agronomic
moisture stress Temperature extremes pH extremes Biotic stress practices
Terminal Heat stress; humid P and N deficiency/efficiency Root rots Stubble retention
Pre-anthesis Heat stress; dry Deficiency (e.g. zinc) Nematodes Zero tillage
Residual moisture Cold stress Toxicity (e.g. boron) Foliar pathogens Crop rotations
Reduced irrigation Cold stress-late frost Acid soils, mineral Shifting cultivation
General low rainfall Acid soils, volcanic/organic Water harvesting
Shallow, marginal, Alkaline soils
infertile, eroded lands

this may simply reflect a lack of variability for key
determinants of adaptation to conservation tillage
in the genotypes tested. At CIMMYT, all materials
targeted to marginal areas are being screened for
their ability to emerge and establish from varying
sowing depths. Key diseases such as yellow spot
and crown rot, which sometimes increase under
conservation tillage, are now routinely tested and
evaluated. A key objective for the future will be to
encourage regional cooperators to move their key

yield evaluation trials on farm. One of the
limitations of the international yield trial testing
network over the years has been the over-
representation of experiment research stations in
the data returned. Very few trials have been sown
under farmer-managed conditions. It will become
increasingly important to move these trials on
farm, as producers begin to adopt more sustainable
farming practices.

Increasing Durum Wheat Yield Potential

and Yield Stability

W.H. Pfeiffer, K.D. Sayre, and T.S. Payne

It is estimated that global wheat production must
increase by 40% in the next 20 years to meet the
rising demand for wheat grain. Increasing
production intensity in ecosystems that lend
themselves to sustainable intensification while
decreasing the intensity in more fragile ecosystems
may be the only way for agriculture to keep pace
with population (Borlaug and Dowswell, 1997).
Based on projections that per capital land and water
resources will diminish during the current century,
recent studies predict production must increase by
1.6% per annum over the next 20 years to meet the
rising demand for wheat on the global level
(Byerlee and Traxler, 1999; Calderini et al., 1999).
This poses an immense challenge to wheat research
teams, given that recent annual production gains
have been of a smaller magnitude.

Hence, greater reliance on maximizing production
efficiency, or grain yield potential (GYP), under
various agroecological scenarios will be required.
Environmental, cultural, and political sustainability
will define the focus of our research agenda.
CIMMYT aims to contribute to this effort by
protecting past achievements in yield potential and
adaptation through continuing an aggressive
program of incorporating resistance to abiotic and
biotic stresses. This strategy capitalizes on newer
empirical methods, advances in information
technology, morphological and physiological
markers, a broad genetic resource base, and
emerging biotechnologies. To date, high rates of
progress in raising GYP have been achieved in
spring durum and bread wheats.

Inception of the CIMMYT Durum Wheat
Breeding Program
Systematic durum wheat enhancement at CIMMYT
in Mexico started in 1965 under the leadership of
Dr. Norman E. Borlaug. Early breeding ventures
focused on the introgression of dwarfing genes and
alleles for photoperiod insensitivity, improvement
of floral fertility, and enhanced biotic stress
resistance. Interestingly recent publications suggest
re-visiting these options (e.g., photoperiod
insensitivity). Breeding in Mexico concentrated on
agronomic components associated with high
genetic yield potential and wide adaptation in
combination with quality attributes. The target
areas were irrigated, subtropical environments, the
areas where the Green Revolution began.

The CIMMYT durum project became international
in the late 1960s, once the agronomic problems of
the first semidwarfs (e.g., sterility) were solved.
Varieties such as Jori 69 and other germplasm
products were developed for a wider range of
agroecological conditions and were adopted in a
number of countries. After spillovers to other
agroecological zones became evident in the 1980s-
genotypes from traditional durum growing areas
were heavily used as progenitors-breeding
objectives were expanded to include high rainfall
and moisture-stressed environments, with less
attention given to GYP improvement per se.

The international reach of the durum breeding
program is reflected in the adoption of its hallmark
cultivars, such as Cocorit 71, Mexicali 75, and
Yavaros 79, which are still widely grown in many
countries. Yavaros 79, for example, has been

released in more than 30 countries under more than
40 names. The next generation of durum varieties,
released in the 1980s (e.g., Altar 84 and Aconchi 89)
trace back to breeding based on the ideotype
concept. Common features are upright leaf
characteristics derived from the Shearwater genetic
stock and significantly improved end-use quality
(yellow pigment and gluten characteristics).

Progress in Raising the
Genetic Yield Potential
To gauge historic progress due to breeding, the
relative performance of these five cultivars were
assessed in maximum yield potential trials (MYPT)
conducted at Cd. Obregon, in northwest Mexico.
Improvements in grain yield were associated with
increased biomass yield (Figure 1), though harvest
index decreased. Changes in grain yield were due
to increased grains m-2 via more grains spike .
Additionally, rate of grainfill increased, cultivars
headed and matured later, and had improved test

Genetic progress in CIMMYT durum germplasm
developed during the past decade was investigated
by comparing the best performing durum

Grain Biomass/day,

Veg. Growth Rate

Straw Y,-.1 Ii

Days Maturity

....... 70s Mexican Varieties
-.i-. Yavaros 79
Grain Yield (t/ha) Yavaros79
n Yd 80s Mexican Varieties

Harvest Index



1000 g Weight
Figure 1. Comparison of agronomic components of the
highest yielding early 1970s (Cocorit 71, Mexicali 75),
Yavaros 79, and 1980s (Altar 84, Aconchi 89) durum wheat
varieties evaluated in maximum yield potential trials at Cd.
Obregon 1991-1999.

genotypes from the MYPTs. The mean of the five
hallmark checks was used for comparison to
minimize the effect of individual genotype x
environment interactions. These comparisons
retrospectively chart changes that have occurred
through genotypic improvement suggesting
strategies to affect improvement of yield per se in
the future.

For the past decade, elite germplasm exhibited
genetic advances for nearly all the agronomic
components (Figures 2 and 3) with the greatest
changes observed in grain yield, biomass, and
grains m-2. Increases in biomass production rate
from crop emergence to physiological maturity and
from anthesis to physiological maturity were high.
Most recently, increases in both spikes m-2 (+8.9%)
and grains spike-' (+7.2%) resulted in a dramatic
rise of +16.9% for grains m'2. Grain biomass
production rate (+16.6%), spike weight (+4.8%),
and vegetative growth rate (+4.5%) all increased,
while the downward trend in 1000-grain weight (-
2.8%) continued. More recent genotypes are later in
heading and maturity, with a surprisingly shorter
grain-filling period.

--.. Three Highest Yielding
Grain Yield 70s & 80s Varieties

Grain Biomass/day Biomass

Veg. Growth Rate 90 Harvest Index

I8 17 40

Straw Yield """"' Spikes/m2

Days Maturity / Grains/Spike

Plant Height Grains/m2

Test Weight

Figure 2. Comparison of agronomic components of the three
respective highest yielding durums compared with check
varieties (Cocorit 71, Mexicali 75, Yavaros 79, Altar 84,
Aconchi 89) evaluated in maximum yield potential trials at
Cd. Obregon 1991-1999.

Strategies for Further
Improving Yield Potential
"Balancing" yield component
architecture and biomass
Contrasting the performance of top yielding
durums with top yielding bread wheat genotypes
may produce models for identifying alternate
avenues to obtaining higher yield for either crop.
Pfeiffer et al. (1996) suggested that lower numbers
of spikes m-2 and grains m-2 in durums compared
with bread wheat should receive special attention
in durum improvement, since past experience
indicated superior bread wheat performance was
associated with number of spikes m-2. Figure 4
discloses a gradual correction of this delinquency
in contemporary durum wheats, revealing a
converging of yield architecture in durum and
bread wheat.

Earlier efforts to increase biomass focused on
manipulating spikes m-2 and, later, on augmenting
the number of grains spike-', both of which are
traits suitable for phenotypic selection. The avenue
of selecting for grains m-2 via a higher number of
grains spike-1 proved superior in raising GYP.

Negative effects on spikes m-2 were minor and
1000-grain weight could be maintained. Over 1997-
99, the simultaneous increase in both spikes m-2
and grains spike-1 produced the highest increase in
grains m-2, GYP, and biomass. The balance in yield
components may have approached a near optimal
constellation, as results from crop comparison
suggest. With limited scope for increasing the
partitioning of assimilates to the grain, future
progress has to be based on increased biomass.

Exploring physiological strategies to
enhance grain yield potential
Physiological strategies that can be applied
empirically to accelerate the rate of breeding
progress include increase radiation use efficiency
(RUE) and, therefore, total plant biomass, increased
grain number, and increased kernel weight. These
three strategies do not address the issue of how to
provide extra assimilates during the spike growth
period (i.e., booting) so that higher grain number
and grain weight potential can be achieved. Such
strategies are discussed in more detail elsewhere
(Reynolds et al., 1999; Reynolds et al., 2000). These
strategies should be incorporated into analytical
and empirical selection approaches.

Grain Yield
Harvest Index
Straw Yield
1000 G Weight
Spike Weight
Kernel G Rate
Biom Prod Rate
Grain Biom Prod Rate A
Grain Biom Prod Rate B
Vegetative Growth Rate
Days Heading
Days Maturity
Grainfill Duration
Plant Height
Test Weight


E 1997-99
E 1994-96
N 1991-93

-5 0 5 10
% Difference from check average

Grain Yield
Harvest Index
Straw Yield
1000 G Weight
Spike Weighf
Kernel G Rate
Biom Prod Rate
Grain Biom Prod Rate A
Grain Biom Prod Rate B
Vegetative Growth Rate
Days Heading
Days Maturity
Grainfill Duration
Plant Height
Test Weight

-25 -20

15 20



] 1997-99



-10 0 10
% Difference from bread wheat

Figure 3. Changes in agronomic components in durum in
three time periods: comparison between the respective 3
highest yielding lines and 5 historical checks.
Data source: Agronomy yield trials, 1991-1999.

Figure 4. Changes in agronomic components in durum in
three time periods: comparison between the respective 3
highest yielding durum and bread wheats.
Data source: Agronomy maximum yield trials, 1991-1999.

20 30

- .I-


Parallel enhancement of yield components, which
determine grains m-2, may be recommended to
minimize competition among yield factors with
overlapping developmental stages. A further
expansion of the duration of the reproductive
phase or higher growth rates during the different
phenological stages should result in higher
biomass during this presumably source-limited

Determination of individual grain weight is
essentially independent of yield components
associated with grains m-2. Nevertheless, grains m-2
and 1000-grain weight are negatively associated, as
the decline in grain weight over time has been
over-compensated by an increase in grain number.
Several assumptions regarding this relationship
have been discussed in the context of sink-source
relationship to enhance GYP (Richards 1996; Slafer
et al., 1996). Given high trait heritability and the
immense genetic variation for 1000-grain weight
(with maximum values above 75 mg grain-'),
improvement of grain size, ceteris paribus, is a
promising strategy from a breeding perspective to
raise yield per se. Heterosis for grain size in wheat
and triticale hybrids, the primary trait affected,
indicates enormous potential supporting a
hypothesis that gains can be achieved without
sacrificing grains m-2.

Stabilizing improved yield potential
Achievements in improving GYP can be traced to
concomitant improvements in raising yield per se
and increasing yield stability. MYPT data reveal
that in years with an overall performance below
the long-term average, more recently developed
genotypes exhibit greater performance stability
than the hallmark checks (Pfeiffer et al., 1996).
Superior spatial, temporal, and systems stability
can be combined with maximum yield per se.
However, while current GYP stabilization efforts
have emphasized individual buffering of
homozygous genotypes, greater consideration
should be given to population buffering effects in
heterozygous populations and different population
structures in future breeding efforts.

Future Challenges
Increased GYP growth rates must match future
demands for food. To achieve anticipated
production levels, breeding for realized GYP
should emphasize enhancement of yield per se and
GYP stability through integrated, interdisciplinary
approaches that take into account environmental
sustainability. This challenge requires concerted,
complementary efforts to gather a critical mass of
scientists and achieve essential operational sizes;
sound hypotheses and strategies, translated into
breeding objectives; free exchange of germplasm
and information; and dynamic cooperation among
the global community of scientists. Each one of
these requirements must be met if we are to
accomplish our common mission: the alleviation of
poverty and hunger.

Borlaug, N.E., and Dowswell, C.R. 1997. The acid lands: One of agriculture's last
frontiers. In: Plant-Soil Interactions at LowpH. Moniz, A. C. et al. (eds.). Brazilian
Soil Science Society, Brazil. pp. 5-15.
Byerlee, D., and Traxler, G. 1999. Estimation of actual spillovers of national and
international wheat improvement research. In: The Global Wheat Improvement
System: Prospects for Enhancing Efficiency in the Presence of Spillovers. Maredia,
M.K. and Byerlee, D. (eds.). CIMMYT Research Report No. 5. Mexico, D.F.:
CIMMYT. pp. 46-59.
Calderini, D.F., Reynolds, M.., and Slafer, G.A. 1999. Genetic gains in wheat yield
and main physiological changes associated with them during the 20th century. In:
Wheat: Ecology and Physiology of Yield Determination. Satorre, E.H. and Slafer,
G.A. (eds.). Food Products Press, New York.
Pfeiffer, W.H., Sayre, K.D., and Mergoum, M. 1996. Enhancing genetic grain yield
potential in durum wheat and triticale. In: Increasing Yield Potential in Wheat:
Breaking the Barriers. Reynolds, M.P, Rajaram, S., and McNab, A. (eds.).
Mexico, D.F.: CIMMYT. pp. 208-213.
Reynolds, M.P., Sayre K.D., and Rajaram S. 1999. Physiological and genetic changes
in irrigated wheat in the post green revolution period and approaches for meeting
projected global demand. Crop Sci 39:1611-1621.
Reynolds, M.P, Van Ginkel, M., and Ribaut, J.-M. 2000. Avenues for genetic
modification of radiation use efficiency in wheat. J. Exp. Botany (in press).
Richards, R.A. 1996. Increasing the yield potential of wheat: Manipulating sources
and sinks. In: Increasing Yield Potential in Wheat: Breaking the Barriers.
Reynolds, M.P, Rajaram, S., and McNab, A. (eds.). Mexico, D.F.: CIMMYT. pp.
Slafer, G.A., Calderini, D.F., and Miralles, D.J. 1996. Yield components and
compensation in wheat: Opportunities for further increasing yield potential. In:
Increasing Yield Potential in Wheat: Breaking the Barriers. Reynolds, M.P,
Rajaram, S., and McNab, A. (eds.). Mexico, D.F.: CIMMYT. pp. 101-133.

A New Approach to Triticale Improvement

A.R. Hede

Humankind faces an unprecedented challenge in
the next century: the need to more than double the
world's food supply in response to rising
populations and increased incomes. The global
demand for cereals will grow dramatically due two
factors: an increase in direct consumption demand
for grain, as well as increased demand for animal
feed (to satisfy, in turn, a growing demand for meat
products). The way forward will be through
significantly increasing the yield potential of the
world's major crops, and in some cases developing
highly productive new crops that fit into specific
agricultural niches.

One of the most promising crops in the latter
category is triticale (X Triticosecale Wittmack), a
man-made cross between wheat and rye. Triticale
combines many of the best qualities of both its
parents: the robustness of rye (adaptability to
marginal soils, drought tolerance, winter hardiness,
disease resistance, and low input requirements
relative to wheat) and wheat's end-use qualities
(such as its flavor and suitability for making
numerous products for human consumption).

Advantages of the New Triticales
In the last 40 years, triticale has progressed from
being an agricultural curiosity to being cultivated
on more than 3 million ha worldwide. Two factors
have contributed to its popularity: considerable
improvements in its yield potential and grain
quality, and a growing appreciation of the
particular advantages it has over other food and
feed crops such as wheat, oats, barley, rye, and

Several types of triticale are now available. Some
produce good quality flour for use in cookie,

flatbread, and pasta production, and can be mixed
with wheat flour for making bread. Other triticales
have been developed as dual-purpose (feed and
forage) sources for livestock. In preliminary studies,
the latter types have been shown to have
significantly better nutritional profiles (better
amino acid composition, fiber content, palatability,
and more metabolizable energy) for animal
consumption than conventional grains or forage
crops. In the medium term, it appears that one of
triticale's competitive niches may be as a feed crop.

Triticale's other niche is an ecological one. It
outshines most other cereals under agronomically
stressed conditions such as:

* Drought-prone environments. Anecdotal evidence
suggests that triticale requires approximately 30%
less water to produce the same amount of biomass
(grain and forage material) as wheat, sorghum,
oats, or ryegrass;
* Acid soils. Such soils have a high soluble
aluminum content toxic to cereals, and cover more
than 100 million ha of potentially arable land.
Recent varieties of triticale yield at least .i r more
than either wheat or barley on these soils.
* Sandy (low-nutrient) and saline soils. Experiments
with triticale in sandy soils (e.g., in North Africa)
show the crop outyields wheat and barley by
approximately 1 On saline soils, triticale yields
some I r, more than bread and durum wheats, but
is not quite as productive as barley.
* Insect- and disease-infested environments.
Triticale has better resistance than wheat and barley
to such major insect pests such as Hessian fly
(endemic in North Africa) and Russian wheat
aphid, as well as better tolerance to plant diseases
such as the cereal rusts, barley yellow dwarf, and
several foliar diseases.

Taken together, these factors suggest that triticale is
an ideal crop for future cultivation in stressed
agricultural environments in South America
(Argentina, Brazil, and Uruguay, especially on the
continent's vast acid soil expanses), North Africa,
Kenya, South Africa, and India. It could have
particular advantages in countries that are currently
importing grains for livestock feed.

Progress in grain yield potential
Since the establishment of the CIMMYT triticale
breeding program in 1964, improvement in realized
grain yield potential has been remarkable. In 1968,
at Ciudad Obregon, Sonora State in northwest
Mexico, the highest yielding triticale line produced
2.4 t/ha with a test weight of 65.8 kg/hl. Eleven
years later under similar conditions the best triticale
line yielded 8.5 t/ha with a test weight of 72 kg/hl.
Triticale's yield potential has continued to increase
in the subsequent 10 years of breeding at CIMMYT.

Under near optimal conditions at Cd. Obregon, a
comparison in maximum-yield trials of triticales
developed in the 1980s and 1990s reveals an
average yield increase of 1.5% /year. Today's high
yielding CIMMYT spring triticale lines (e.g.,
Pollmer-2) have surpassed the 10 t/ha yield barrier
under optimum production conditions at Cd.
Obregon. Figure 1 shows the results of a maximum-
yield potential trial in which 16 triticale, durum,
and bread wheat genotypes were planted in Cd.
Obregon during the 1999/2000 cycle.

Grain yield (t/ha)
M Melga
E9.0 ; 7 Bed (+Fung)
.[ OBed (-Fung)

Triticale Durum wheat Bread wheat
Figure 1. Grain yield potential of triticale, durum wheat, and
bread wheat. Mean of 16 genotypes. Cd. Obregon, Mexico,

Animal feed and forage potential: Better
nutritional balance
In response to specific requirements of end-users
and markets, substantial emphasis has been placed
on developing feed grain, dual-purpose forage/
grain, and grazing types of triticale since 1990.
Major efforts are being invested in developing
facultative and winter habit triticales that will
produce higher forage biomass than spring types.
Forage-specific cultivars have been released in
several countries, where they are being used
successfully for forage, silage, grain/forage, or hay.

Dry matter forage yield (t/ha)

I y' i

Figure 2. Dry matter (DM) forage yield in two cuts (C1 and
C2) and total (TOT) of triticale (TCL) and other cereals at
Salaices, Chihuahua, Mexico, 1998/99.

Protein yield (t/ha)

2 -

0 I

Figure 3. Protein yield (PY) in two cuts (C1 and C2) and total
(TOT) of triticale (TCL) and other cereals at Salaices, Chihuahua,
Mexico, 1998/99.

CIMMYT triticale lines were evaluated for dry
matter production and nutritional value in
northern Mexico. Results of these trials
demonstrated that winter/facultative triticales
significantly outperformed such traditional forage
crops as oat and ryegrass. Trials during the 1998/
99 crop cycle, in which wheat, rye, and barley were
included as checks, produced similar results, with
triticale showing higher dry matter yields and
better quality than any of the other forage crops
(Figures 2-5). Triticale's high forage biomass

Protein yield (t/ha)

S' o o "
Figure 4. Digestible dry matter (DDM) yield in two cuts (C1
and C2) and total (TOT) of triticale (TCL) and other cereals at
Salaices, Chihuahua, Mexico, 1998/99.

ADF and NDF (%)


<-) ,,0,
a'I s i

Figure 5. Acid detergent fiber (ADF) and neutral detergent
fiber (NDF) in two cuts (C1 and C2) and total (TOT) of triticale
(TCL) and other cereals at Salaices, Chihuahua, Mexico,

production and forage quality should increase
animal performance, reduce feeding costs, and
generate higher returns. In addition, in many
countries cereal straw is a major feed source for
animals. Under arid and semi-arid conditions,
triticale has been shown to consistently produce
higher straw yields than wheat and barley.

Triticale has clear advantages as an animal feed. Its
amino acid composition fits the nutritional
requirements of monogastrics and poultry very
well. Studies in Algeria and Tunisia have shown
that triticale can substitute for maize (Zea mays) in
poultry feed rations. In Australia farmers have
demonstrated a preference for feeding triticale to
cattle (particularly dairy) because of its superior
metabolizable energy, palatability, and appropriate
fiber content, compared to other grains available
(Cooper, pers. comm.). Similarly, the excellence of
triticale as a total grain ration for pigs is becoming
well known, since, unlike other grains tested, it
does not interact negatively with legumes in the
diet. Thus, in the future chemical analysis (e.g.,
crude protein and metabolizable energy) of
promising triticale lines will become a routine
component of varietal screening at CIMMYT, as a
means of identifying genotypes with desirable
nutritional profiles.

Hybrid Triticale
Given the dramatic demand for food, feed, and
fodder in 21st century and the commercial success
of other hybrid crops, the use of hybrid triticales as
a strategy for sustainably enhancing grain and
forage production in favorable as well as marginal
environments is promising. Triticale displays the
pollination control traits required for hybrid seed
production: excellent anther extrusion, large anther
size and an associated large amount of pollen, and
excellent cross pollination capacity.

Furthermore, in many countries distribution of non
pedigreed seed from farm to farm reduces the
return on investment to the cultivar developer,
which diminishes the incentive to conduct crop
research, and in the end, reduces the dissemination

of improved seed and new technologies to farmers.
This problem would be reduced with hybrid
triticale. In hybrids maximum levels of heterosis are
expressed in the F1 hybrid, so in order to achieve
maximum yields, pedigreed seed would have to be
purchased every year.

Chemical hybridizing agent (CHA)
Early research at CIMMYT on triticale hybrids
aimed at evaluating heterosis for agronomic traits
in hexaploid triticale hybrids produced using a
chemical hybridizing agent. Thirty-one hybrids
from 3 male and 15 female elite hexaploid spring
triticales were produced by CHA. All triticales used
were complete R-genome types, except one 2D(2R)
chromosome substituted type, which was used as a
male parent. Male parents were selected based on
performance under high production conditions.
Female parents were selected based on
performance in different agro-ecological zones and
for their contrasting yield component expression.
Yield trials including CHA hybrids and parents
were conducted under high production conditions
in Cd. Obregon during the 1995-96 and 1996-97
growing cycles to evaluate grain yield and
agronomic traits.

A combined analysis of 1995-96 and 1996-97 data
revealed, on average, 9.5% mid-parent and 5.2%
high parent heterosis for grain yield. Maximum
heterosis values greater than 20% were observed
for grain yield in high-parent (22.9%), mid-parent
(24.9%), and low parent (28.9%) comparisons.

Mid-parent heterosis for agronomic components
were observed in: biomass (9.1%), straw yield
(9.0%), 1000 grain weight (11.4%), culm weight
(12.0%), and spike weight (12.4%). This differential
contribution of yield components to grain yield
heterosis could be exploited in designing hybrids.
Several hybrids revealed superior biomass
performance and would be preferred for forage
utilization, e.g. whole crop silage production.

Cytoplasmic male sterility (CMS)
Several alien cytoplasms, such as Triticum timopheevi
Zhuk., Aegilops sharonensis, Aegilops juvenalis,
Aegilops heldreichi and Aegilops ovata cytoplasm,
cause male sterility in wheat and triticale. Triticum
timopheevi Zhuk. cytoplasm has been used in
different countries to produce commercial bread
wheat hybrids. In wheat, fertility restoration genes
from Triticum timopheevi Zhuk. have been
introduced and are employed along with modifier
genes for fertility restoration. In contrast to wheat,
most triticales carry fertility restoration genes on
the R genome.

In 1994, CIMMYT started a small applied research
project on hexaploid spring CMS triticale hybrids
based on T. timopheevi Zhuk. cytoplasm. In the first
phase, elite CIMMYT spring triticales were crossed
onto a CMS source to identify non-restoring lines
(potential females in CMS hybrids) and lines
carrying restorer genes (potential males). Out of 25
genotypes that exhibited complete or partial
sterility in the Fl hybrid generation (CMS source x
tester line), 18 lines were retained as potential CMS
recipients and subsequently backcrossed. After four
backcrosses, 300 test hybrids were produced during
the 1997 El Batan crop cycle from 15 CMS lines and
27 male lines. The restoration capacity of the elite
triticales used as males had been determined in the
Fl hybrid generation. Two hundred CMS hybrids
and their parents were tested under high
production conditions at Cd. Obregon during the
1997-98 growing cycle to evaluate grain yield.

Analysis of 1997-98 data revealed, on average, 9.1%
mid-parent and 3.3% high parent heterosis for grain
yield. Heterosis values for grain yield in mid-parent
comparisons were: 29 hybrids: 1-5%, 34 hybrids: 6-
10%, 41 hybrids: 11-15%, 31 hybrids: 16-20%, 17
hybrids: 21-30%, and 3 hybrids: more than 30%
with a maximum of 48%. Heterosis values for grain
yield for high-parent comparisons were: 42 hybrids:
1-5%, 35 hybrids: 6-10%, 28 hybrids: 11-15%, 11
hybrids: 16-20%, 1 hybrid: 21-30%, and 3 hybrids:
more than 30% with a maximum of 44%.

Average grain yield of the experiment was 7.22 t/
ha. CMS hybrid grain yields varied from 9.48 t/ha
to 5.86 t/ha and averaged 7.32 t/ha. Grain yields
for parents ranged from 8.26 t/ha to 5.32 t/ha and
averaged 6.81 t/ha. Results indicate that high
absolute grain yields were due to high heterosis.
Grain yield of the top yielding CMS hybrid
compared with the top yielding parent was +15%.

The CIMMYT triticale program continues to
emphasize the identification of new superior hybrid
combinations, and during the 1998-99 crop cycle,
more than 500 new hybrid combinations were
made. These were evaluated for agronomic traits
and disease resistance in two environments, and the
superior 120 hybrid combinations were planted in
replicated yield trials under optimal and drought
conditions at Cd. Obregon during the 1999-2000
growing cycle. The experiments demonstrated that
there is no clear relationship between high parent
heterosis under irrigated and drought conditions,
although a few hybrids demonstrated high levels of
heterosis under both types of conditions (Figure 6).
High parent heterosis levels of the best hybrids
were between 10-20%, and these superior triticale
hybrids outyielded the check cultivar (Pollmer 2) by
up to 20% (Figure 7).

Possible impacts of hybrid triticale
High heterosis for value-added traits suggests the
feasibility of developing commercial triticale
hybrids with substantial gains in genetic grain and
forage yield potential, given the existing genetic


variation. Hybrids can be successfully designed
from inferior yielding parents carrying special
attributes (for example, for disease resistance),
involving fewer adapted alien sources to exploit
potentials of marginal environments, or unique
end-use quality traits. High heterosis in hybrids
involving 2D(2R) substitution types suggests the
presence of contrasting heterotic groups between
the complete R and substituted 2D(2R) genepools
and/or heterotic effects from D genome
chromosomes. As with most commercial hybrid
crops, an increase in heterosis can be anticipated
along with the identification of heterotic genepools
and directed breeding efforts for hybrid

High parent heterosis drought

-40 **- **- *-
0*.* *0

20* wr ** **
** *00^* *_

-40 ----


-30 -20 -10 0 10
High parent heterosis irrigated

20 30

Figure 6. Relationship between high parent heterosis under
irrigated and drought conditions, Cd. Obregon, Mexico,

H1 H5 H10 H15 H20 H25 H30
Figure 7. Grain yield as % of check (Pollmer 2) and high and low parent heterosis of selected triticale hybrids, under irrigation,
Cd. Obregon, Mexico, 1999/2000.

The high cost of hybrid seed is one of the major
limiting factors for the commercialization of hybrid
wheat. Experience at CIMMYT shows that for
triticale, costs of hybrid seed production are
substantially lower when compared with wheat
due to high, close-to-normal seed set in hybrid
production plots. Furthermore, fewer male
pollinator rows need to be planted. CMS hybrids
show clear advantages over CHA hybrids in terms
of seed production costs. Production of CHA
hybrids does involve substantial costs due to
determining the dosis of the gametocide,
monitoring seed production fields to optimize the
application of the chemical hybridizing agent,
gametocide product costs, and royalties for the
gametocide. Furthermore, male pollinators can be
blended with CMS females and planted as mixture

for hybrid seed production to further reduce costs.
This practice is common in hybrid rye production
in Europe.

Lack of uniformity in CMS hybrids and a certain
percentage of the male in hybrid seed are likely
irrelevant, e.g., for forage and grazing hybrids.
Moreover, forage/grazing CMS hybrids do not
require fertility restoration in the hybrid; hence,
hybrid development is less complicated and costly.
On the other hand, the costs of developing CMS
hybrids are much higher than for developing CHA
hybrids, and crop improvement is complicated and
requires a considerable amount of resources.
Molecular markers for restorer/non-restorer genes
could dramatically reduce the cost of developing
CMS hybrids (> 75%).

Adaptation of Winter Wheat to

Central and West Asia

H.-J. Braun,' M. Mergoum,1 A. Morgounov,2 and J. Nicol3

Winter and facultative wheats are grown on an
estimated 43 million ha in Central and West Asia
(CWANA), Central and Eastern Europe (CEE), and
Russia. Wheat acreage of the mega-environments
(ME), as defined by CIMMYT, is for winter wheat:
ME 10 (irrigated) 1.5 million ha, ME 11 (high
rainfall) 25 million ha and ME 12 (rainfed) 7
million ha. Facultative wheat area in ME 7
(irrigated) is 2.8 million ha, ME 8 (high rainfall)
1.35 million ha and ME 9 (rainfed) 5.5 million ha.
Around 65% of the winter and facultative wheat
area in Central Asia and the Caucasus is irrigated,
compared to 20% in West Asia and North Africa.

The Turkey CIMMYT / ICARDA International
Winter Wheat Improvement Program (IWWIP)
focuses on particular wheat areas in CWANA,
mainly ME 7 and 9 and ME 10 and 12. In CWANA,
winter and facultative wheats are produced mainly
between 320 to 420 N latitude. Annual precipitation
is mostly below 400 mm, summers are hot and dry,
and winters are often moderate. The most
important wheat diseases are yellow rust, common
bunt, leaf rust, tan spot, and dryland root rots. In
contrast, winter wheat areas in CEE and Russia
receive more than 500 mm of rain. Wheat areas are
located between 420 to 550N latitude and classified
mostly under ME 11. The most important diseases
are leaf rust, powdery mildew, fusarium head scab,
Septoria spp., and barley yellow dwarf (BYD).
Winters are often severe, and winterkill is
frequently observed.

Based on climatic and geographic differences,
adaptation requirements for wheats in this large

area vary greatly. The adaptation of wheat cultivars
developed by NARSs and the IWWIP for the mega-
environments in CWANA and CEE is evaluated in
yield trials targeted for the different MEs. The
Winter Wheat East European Regional Yield Trial
(WWEERYT) is targeted for the high rainfall areas
in CEE. The irrigated areas in CWANA are
addressed through the WWEERYT and the Elite
Yield Trial for irrigated areas.

First and Second Winter Wheat East
European Yield Trial (WWEERYT)
The WWEERYT consists of 60 elite cultivars plus
four checks. The lines are submitted by 13 wheat
programs in CEE, 4 programs in CWANA, 3
programs in the Great Plains of the US, and the
IWWIP. The objective of this nursery is to evaluate
elite germplasm from regional wheat programs
across the region and to give NARSs access to these
elite lines for use in their breeding programs or
variety release. Co-operators are asked to sign a
materials transfer agreement (MTA) before they
receive the material.

In 98-99 and 99-00 the nursery was grown at 22 and
19 locations, respectively. Plot size at each location
varied from 6 m2 to 12 m2 and the nursery has 3
replications. Plot size was large because several co-
operators lack sowing equipment for smaller plots.
The advantage of big plot size is that it increases
the reliability of yield data. Table la and b lists
entries whose yield was not different from the
highest yielding entry either across all locations or
across locations in CWANA or CEE. Yield is also
given in % of the best of four local checks.

1 CIMMYT-Turkey;
2 CIMMYT-Kazakstan;
3 CIMMYT-Mexico

Only a few cultivars performed well in both Romania and two from the IWWIP, performed well
regions. In the 1st WWEERYT, ERYT6221 from in both regions.
Mironovsk in Ukraine, derived from a mutation
In the CEE region, the highest mean yield was
program, was equal or better than checks in 13
obtained in the 1st WWEERYT by cultivars from
locations. The parents, TXGH2895 and Trakia, were
programs located in CEE and TAM 200 from Texas
lines from US, Texas, and Bulgaria. Agri/ /Bjy/Vee pro s lted 2 f e
A&M. Yields of cultivars developed by the IWWIP
had the second highest mean yield across locations
were different from those of the best entries, and
and was equal or better than the best of four checks
at 10 locations. Yuna, a winter hardy facultative equal or slightly lower than that of the local check.
at 10 locations. Yuna, a winter hardy facultative
In the 2nd WWEERYT, cultivars from CEE, Texas,
type from Krasnodar, Russia, also performed well
in both rei. In te and the IWWIP had highest mean yields. The
in both regions. In the 2nd WWEERYT, five
.... IWWIP lines are derived from selections made in

cultivars, one each from Bulgaria, Texas, and


Table la. Grain yield of highest yielding entries in 2nd WWEERYT (1999-2000) across 18 locations and across the 7 locations
in CWANA and 11 locations in Eastern Europe.
Total East Europ. countries CWANA countries No. trials entry
yield not sign. diff.
Entry Cultivar Origin Mean Rnk % LC Mean Rnk % LC Mean Rnk % LC from top yielder
40 Local Check 6049 *1 1 100 6425 1 100 5458 12 97 9
52 TODORA BG 5962 2 99 6289 3 98 5448 14 97 11
56 SOM-5 TCI 5944 3 98 6090 8 95 5714 4 102 11
59 BOEMA RO-FL 5942 4 98 6019 13 94 5821 3 104 11
64 TX96V2427 US-TX 5936 5 98 6087 9 95 5698 5 101 8

22 DOGU88//TX71
26 SHARK-1
25 KINAC197


5904* 6
5867* 8
5843 10
5650 19
5288 43
5023 59

6126 *
6293 *

95 5513 10 98
90 5995 1 107
91 5876 2 105
98 4640 52 83
84 5162 25 92
81 4725 49 84

n=16 locations

Table lb. Grain yield of highest yielding entries in 1st WWEERYT (1998-1999) across 18 locations and across the 7 locations
in CWANA and 11 locations in Eastern Europe.
Mean Mean EEurope Mean CWANA No. trials entry
yield not sign. diff.
Entry Cultivar Origin kg/ha % LC kg/ha Rnk % LC kg/ha Rnk % LC from top yielder
52 ERYT26221 UKR-MI 6195 1 104 6067 1 108 6534 1 107 13
60 LOCAL CHECK 2 5941 2 100 5593 5 100 6072 9 100 5
9 AGRI/BJY//VEE MX-TCI 5834 3 98 5435 17 97 6513 2 107 7
35 UKRAINKA UKR-OD 5829 4 98 5701 2 102 5719 26 94 6
47 YUNA RUS 5796 5 98 5589 6 100 5828 19 96 6
37 SELYANKA UKR-OD 5700 7 96 5586 7 100 5569 38 92 4
26 BOKA CZ 5692 8 96 5390 21 96 6103 7 100 4
23 MV MADRIGAL HUN-MV 5661 9 95 5323 27 95 6184 5 102 4
4 KINAC197 MX-TCI 5621 14 95 5103 37 91 6284 3 103 5
27 SARKA CZ 5511 24 93 5326 25 95 6132 6 101 5
63 TAM200 US-TX 5480 27 92 5612 3 100 4986 59 82 6
53 MNCH-24 MX 5219 44 88 4930 45 88 6221 4 102 5
2 SERI MX-TCI 4536 61 76 4355 61 78 5145 55 85 0
1 BEZ RUS 1818 64 83 4652 59 83 5456 45 90 2
MEAN 5238 5067 5583 n=16 locations
LSD 508 574 642
*1 not significantly different from highest yielding entry using LSD 5%.


In both years three of the four highest yielding
entries in CWANA originated from IWWIP. In
general, IWWIP lines selected in either Turkey or
Mexico perform well in CWANA (see results
below). However, they often lack the
winterhardiness required in CEE, since winters in
Turkey and Mexico are much milder than in CEE.
Furthermore, the IWWIP emphasizes winter x
spring crosses. Cultivars derived from such crosses
have sufficient cold tolerance for most areas in
CWANA. An important factor that limits
adaptation is the different disease spectra in
CWANA and in CEE. Most IWWIP cultivars are
resistant to yellow rust virulences prevailing in
CWANA, whereas many lines from CEE and the
Great Plains are susceptible. On the other hand, the
widely adapted cultivars from CEE combine
resistance/ tolerance to powdery mildew, septoria,
fusarium, and leaf rust, diseases of only local
importance in the facultative and winter wheat
areas of CWANA.

Though few lines perform well in both regions, in
general there is a clear separation. TAM 200 and
MV Martina had the second and third highest yield
in 1st and 2nd WWEERYT, respectively, but were
among the lowest yielding entries in CWANA.
Similarly, Shark-1 and Kinaci 97 had the highest
yield in CWANA, but only mediocre yields in CEE.
This is not surprising, since yellow rust, the main

disease in CWANA, is important only in Romania,
whereas most lines selected in CWANA are
susceptible to powder mildew, fusarium, leaf rust,
and septoria, and less winter-hardy in the CEE

Fourth Elite Yield Trial for
Irrigated Areas (EYT-IRR)
The Elite Yield Trial is grown in three replications
and has 25 entries, including four long-term checks
(Bezostaya, Kinaci, Katia, and Sultan) and one local
check. Data from 23 sites in CWANA and from one
site each in Morocco, Portugal, and Spain were
available for analysis. Results for the checks and
the highest yielding entries across eight locations in
Central Asia-Caucasus, six locations in Iran, nine in
Turkey, and five on the Anatolian Plateau are given
in Table 2.

The highest yielding entries were Burbot-4,
RPB868 / CHRC / / UT1567.121 / 3 / TJB368.251/
OYC, and Shark/F4105. Burbot derives from an F3
from Oregon and is relatively late maturing. It
takes advantage of the full-irrigation regimes
applied mostly on experiment stations. Both entries
outyielded the best long-term checks by 2-14% and
the local check by 5-20% in all regions. The highest
yield advantage (14 and 11%) was obtained in trials

Table 2. Mean grain yield of highest yielding entries in 4th EYT irrigated and % of yield of best of 5 checks (BC%) across all 26
locations and across 8 locations in Central Asia/Caucasus, 6 locations in Iran, all 9 locations in Turkey, and 5 locations on the
Anatolian Plateau.
Grand mean C-Asia/Caucasus Iran Turkey Turkey-Anat. Plat.
26 sites 8 sites 6 sites 9 sites 5 sites
Entry Name kg ha-1 % BC kg ha-1 % BC kg ha-1 % BC kg ha-1 % BC kg ha-1 % BC
1 BEZOSTAYA 3986 89 3417 80 4097 87 4836 90 5171 91
2 KINACI 4495 100 4288 100 4735 100 4849 90 5371 95
3 KATIA 4503 100 3752 88 4629 98 5373 100 5681 100
4 SULTAN 4365 97 4017 94 4480 95 5162 96 5493 97
5 LOCAL CHECK (LC) 4401 98 4048 94 4560 96 4840 90 5218 92
9 Shark/F4105 4922 109 4760 111 4806 102 5543 103 5751 101
14 BURBOT-4 4955 110 4870 114 4831 102 5588 104 5996 106
15 TAM200/KAUZ 4763 106 4759 111 4740 100 5213 97 5528 97
24 Shark/F4105 4735 105 4756 111 4074 86 5654 105 6018 106
25 TAM200/JI5418 4735 105 4248 99 4511 95 5583 104 5954 105
MEAN 4421 4454 4821 5472
LSD5 336 708 564 896

in CAC. In Turkey, the advantage over Kinaci 97
and Sultan 95, the latest variety releases for
irrigated areas on the Central Plateau, is 6%. In
Iran, the best check was outyielded by 2% and the
local check by 5%.

This supports data from the WWEERYT that lines
developed by the IWWIP are well adapted across
large areas in CWANA. These lines combine yield
potential with resistance to yellow rust and stable
yields across the region. Kinaci 97 was released in
Turkey, Afghanistan, and Uzbekistan.

At present only in Turkey and parts of Iran is
supplementary irrigation a common procedure; in
most other areas, full irrigation systems are
applied. The latter favor late maturing cultivars.
Due to the catastrophic droughts that have struck
CWANA countries, growing public concern over
water shortages, and increasingly intensive crop
rotations, breeding early maturing cultivars
adapted to supplementary irrigation regimes will
become a high priority in most CWANA countries.
Results from the EYT-IR suggest that lines adapted
to supplementary irrigation systems are already

Progress in raising winter and facultative
wheat yields
Bezostaya 1 was widely grown in CEE until 15
years ago and still is in several countries of
CWANA. This was due particularly to its quality
characteristics and grain plumpness. Bezostaya also
has an excellent winter survival rate, as results of

the Facultative and Winter Wheat Observation
Nursery show. Distributed worldwide, this nursery
includes elite wheat cultivars from Europe, North
America, CWANA, and the IWWIP, but no entries
that are cold tolerant in all environments. This is
understandable, since the development,
maintenance, and breakdown of frost tolerance are
controlled by both genetic and environmental

A large area is still sown to Bezostaya, perhaps
partly due to its ability to cope with the wide range
of stresses in cold environments; in contrast, other
genotypes are more specifically adapted to cold
stresses occurring in either humid or dry areas. This
ability is of particular importance in areas where
agronomic practices and seedbed preparation are
poor, as is the case in large areas of WANA.

Data from the 1st and 2nd WWEERYT and the 3rd
and 4th Elite Yield Trial for irrigated areas were
used to estimate progress in increasing yields of
new cultivars relative to Bezostaya. In total, data
from 24 trials in CEE and 54 trials in CWANA
during 98-99 and 99-00 were considered (Tables 3
and 4). The local check yielded below Bezostaya in
12 trials in CWANA and 1 trial in CEE. In none of
the trials did Bezostaya have the highest yield. The
highest yielding entry outyielded Bezostaya by at
least 20% in 46 of 54 trials in CWANA and in 20 of
24 trials in CEE. In 26 trials in CWANA and 9 trials
in CEE, the best check outyielded Bezostaya by
more than 40%.

Table 3. Fifty-four trials in CWANA and 24 trials in CEE grouped on yield advantage (%) of Local Check and highest
yielding entry compared to Bezostaya. Data from 1st and 2nd WWEERYT and 3rd and 4th Elite Yield Trial (irrigated),
1998-99 and 1999-00.
Frequency of trials
Yield range Central/West Asia Central Eastern Europe
(% Bezostaya) Local check Best entry Trial mean Local check Best entry Trial mean
<100 % 12 0 10 1 0 4
100-110 % 11 3 10 3 1 8
111-120 % 11 5 7 4 3 7
121-130 % 8 10 8 7 5 3
131-140 % 3 10 10 4 6 0
>140 % 9 26 9 5 9 2
Total no. of trials 54 54 54 24 24 24

Progress is also obvious from the number of trials
in which the mean yield of all entries is higher than
the yield of Bezostaya (44 of 54 trials in CWANA
and 20 of 24 trials in CEE). The average yield
advantage of the highest yielding entry and the
local check (using data from each location) was
46% and 27% in the 1st WWEERYT, 46% and 20%
in the 2nd WWEERYT, 86% and 46% in the 3rd
EYT, and 46% and 28% in the 4th EYT.

Similar data are found when the average yield
across locations is used as basis (Table 4). Again,
progress of the highest yielding cultivars over
Bezostaya varies from 20% to 43% in CWANA and
23 to 30% in CEE. Using single-location and across-
location data, it can be concluded that the yield of
recently developed cultivars is at least 25% above
that of Bezostaya.

Root Rot Screening
As noted above, the disease spectra are very
dissimilar in CEE and CWANA, mainly due to
different rainfall patterns. Among the major
diseases in the dryland areas of the West Asia /
North Africa (WANA) region, root rots are also
becoming increasingly important in areas with
supplementary irrigation. In supplementary
irrigation systems wheat is often not irrigated at
the optimum time and can at times suffer from
drought. Under such conditions, losses from
dryland root rots in irrigated plots can be as high
as 50%.

Disease occurrence and frequency vary regionally,
depending on climatic conditions and agronomic
practices. The most commonly reported root rot
pathogens are Cochliobolus sativus, Fusarium

culmorum, Fusarium graminearum (Group 1),
Fusarium avenaceum, and Rhizoctonia cerealis. Root
rots most often affect seedling stand, reduce yield,
and lower grain quality. Typical symptoms include
discoloration and necrosis or rotting of roots,
subcrown internodes, crown, and/or the stem.
Severe root rots cause symptoms such as stunting,
late death tillers, and premature ripening;
bleaching of spikes commonly known as "white
heads" or "dead heads" may occur. Root rots can
be caused by one or a combination of pathogens.

The use of resistant/tolerant cultivars is usually
the most economic, sustainable, and
environmentally sound control method. However,
screening wheat for resistance to the root rot
complex has been hindered by inadequate and
inconsistent inoculation methods, and a lack of
accurate and suitable disease evaluation
techniques. Several studies were conducted in
WANA to identify wheat germplasm resistant to
this complex disease. In Turkey, however, very few
studies have been conducted on root rots, and
practically no screening of winter wheat

Hence, a major effort to address root rots was
undertaken in the IWWIP in the 1999-00 crop
season. One thousand six hundred wheat
genotypes, including most released cultivars and
advanced lines, were artificially inoculated with
the major root rot pathogens (Cochliobolus sativus,
Fusarium culmorum, Fusarium graminearum (Group
1), and Alternaria). Root Rot Screening Nurseries
were planted in Cumra Station, 40 km from Konya
City, Turkey, where root rot is frequently observed.
Each genotype was planted in two adjacent plots (2

Table 4. Mean yield and yield advantage (%) of best entry over Bezostaya across all locations of 1st and 2nd
WWEERYT (18 trials) and 3rd and 4th EYT-irrigated.
Central/West Asia Central Eastern Europe
Yield (kg/ha) Yield (%) Yield (kg/ha) Yield (%)
Nursery Best entry Bezostaya Bezostaya Best entry Bezostaya Bezostaya
1st WWEERYT (21 trials) 6534 5456 120 6067 4652 130
2nd WWEERYT (18 trials) 5995 4725 127 6425 5213 123
3rd EYT-irrigated (19 trials) 5145 3595 143
4th EYT-irrigated (23 trials) 4955 3986 124

rows, 2 m long). One plot was inoculated with a
suspension of root rot spores, and the other plot
(non inoculated) was the check. Root rot was
evaluated from heading to maturity based on plant
stand and white heads.

Results of these studies showed that 17 lines were
tolerant in the most advanced International
Nurseries (FAWWON, EYT, Winter Wheat
Observation Nursery, irrigated and rainfed, and
WWEERYT). Under rainfed conditions, lines
selected from the 4th EYT-RF (FDL4/KAUZ and
AGRI/ NAC/ /KAUZ) and 3rd WON-SA (EBVD99-
6 and CRR/TIA.2/FDL490) showed promise and
are presently being evaluated for the second year
to confirm their tolerance to root rot.

Among the 15 genotypes selected from yield trials
were two widely grown cultivars, Gerek 79 and
Gun 91. The reaction of these two cultivars has yet
to be confirmed. The large areas sown to these
cultivars (more than 1 million ha and 300,000 ha,
respectively) indicate that their tolerance to root
rots is partly responsible for their wide acceptance
by farmers.

In total 225 genotypes (of the 1600 entries tested)
were selected and will be tested in 2000-01 to
confirm their reaction to root rot. Besides these
entries, 1800 new genotypes will be tested for the
first time for root rot reaction under artificial
inoculation using similar techniques.

Nematode and Root Rot Surveys in Syria
and Turkey
In the 1999-00 crop season, scientists from Turkey,
CIMMYT, ICARDA, and France undertook a major
survey of soil-borne diseases in the principal
wheat-growing areas of Turkey and Syria. Its main
objectives were to assess the importance and
distribution of soil-borne diseases and identify the
major causal agents. Fifty-three samples (soil and
roots) were collected in total (23 in Syria and 30 in
Turkey). In Turkey samples were collected at
random every 50 km from Adana- Konya -

In Eskisehir (AARI) migratory nematodes (root
lesion nematode, or RLN, Pratylenchus spp.), cysts
(cereal cyst nematode CCN, Heterodera spp.), and
samples of root rotting fungi (Fusarium spp. and
Bipolaris) were extracted from soil/plant samples
from Turkey. Preliminary results of these analyses
showed that:

* 722 of root samples investigated had CCN cysts.
* .i r of soil samples contained one or both species
of RLN.
* r' of root extractions contained root rots
(Fusarium spp. and/or Bipolaris).
* Fusarium spp. was isolated more frequently (57% of
samples) and Bipolaris less so (17% of samples).
* At least two species of Fusarium were commonly
isolated from roots (F. graminearum and F.
These data confirm results of previous surveys:
that root rots and nematodes are a widespread
constraint for cereal production in Turkey. To
address the root rot/nematode complex, a
CIMMYT pathologist will be based in Turkey.

Farmer Participatory Variety Selection in South Asia

1 G. Ortiz-Ferrara,2 M.R. Bhatta,2 T. Pokharel,3 A. Mudwari,3
D.B. Thapa,4 A.K. Joshi,4 R. Chand,5 D. Muhammad,'
E. Duveiller,1 and S. Rajaram6

The CIMMYT Wheat Program has been associated
with the NARSs of South Asia for the last 35 years.
Over this period, South Asian countries have
identified and released many improved wheat
varieties that have played an important role in
increasing average grain yield and total production
in the region. On average, South Asia maintained
an annual production growth rate of 3.5% from
1985 to 1997 (Pingali, 1999). Despite these
achievements, and due mainly to the high
population growth rate (2.2% per year), by 2020 the
region is expected to face a net trade deficit of 21
million tons of wheat grain, mostly in Pakistan,
Bangladesh, and Nepal (Rosegrant et al., 1995;
Table 1).

Average productivity in the more productive areas
of South Asia (e.g., Punjab of Pakistan and India,
Terai of Nepal, northern Bangladesh) has leveled

Table 1. Wheat production, consumption, and imports (in
millions of tons).
Production Demand Net trade
Region/Country 1990 2020 1990 2020 1990 2020
World 530 841 532 841 -2 0
DC304 409 242 287 62 122
LDC 227 432 289 553 -62 -121
South Asia 66 127 69 148 -3 -21
Bangladesh 1 2 3 6 -2 -4
India 49 96 48 95 1 1
Pakistan 14 27 16 42 -2 -15
Other South Asia 1 1 2 3 -1 -2
Source: Rosegrant et al. (1995).

1 CIMMYT-South Asia Regional Office, Kathmandu, Nepal.
2 NWRP-NARC, Bhairahawa Agric. Res. Station, Bhairahawa,
3 NARC, Agronomic Botany Division, Khumaltar,
Kathmandu, Nepal.
4 Banaras Hindu University, Dept. of Genetics and Plant
Breeding, Varanasi, India.
5 Agha Khan Rural Support Program, Gilgit, Pakistan.
6 Director, Wheat Program, CIMMYT.

off. Since the cultivated area in these countries
increases by only 1% each year, the required jump
in production will have to come from the less
productive areas (e.g., eastern, far eastern, and
central India, hills of Nepal, and northern and
western Pakistan). In these marginal areas, the yield
gap between experiment stations and farmers'
fields is wider than in the more productive
environments of the region. The most commonly
grown varieties are old improved varieties such as
Sonalika and HUW 234, as well as local, low-
yielding, disease-susceptible varieties.

Besides the low adoption rate of improved varieties
in these marginal areas, constraints such as poor
seed production infrastructure and lack of
appropriate technology transfer programs
contribute to the wide yield gap. Another important
factor is the lack of diversity in improved wheat
varieties grown by farmers. This is very risky, since
a single change in the virulence of a foliar pathogen
could cause significant yield losses. Serious yield
losses were reported in Pakistan (and other Asian
countries) in the early 1990s, when the main variety
grown at that time (Pak 81) was hit by a new race of
yellow rust. Table 2 shows the total wheat area,
average yield, production, and estimated area
grown to a single variety in several countries
during the 1999-2000 wheat season.

To help the NARSs of South Asia meet these
challenges, for the past four years the CIMMYT
Wheat Program has made special efforts to
strengthen wheat research focused on the less
productive areas of the region. Besides the ongoing
exchange of germplasm and information, CIMMYT,
through its South Asia regional wheat program, has

Table 2. Wheat production statistics for South Asia, 1999-2000.
Country Area (000 ha) Yield (t/ha) Production (000 t) Area under one main variety (000 ha)
Bangladesh 700 2.4 1680 525 (=Kanchan, 75%)
India (Country) 27000 2.8 75640 4500 (=PBW 343, 16.7%)
India (North*) 5560 4.15 2309 4000 (=PBW 343, 71.9 %)
Myanmar 98 0.9 85 73 (=SKA, 75%)
Nepal 660 1.8 1188 200 (=NL 297, 30%)
Pakistan 9100 2.5 22500 6370 (=Inquilab 91, 70%)
South Asia 37558 2.7 101093 -----
* States of Punjab and Haryana only.

worked hand in hand with regional NARSs on
farmer participatory variety selection (PVS) and
farmer participatory plant breeding (PPB). Thanks
to the active participation of resource-poor farmers,
both approaches, especially PVS, have proved
effective in promoting the adoption of new wheat
varieties and of relevant site-specific resource
conservation techniques (RCTs).

Farmer Participatory Approaches
Farmer participatory approaches for identifying or
breeding improved crop cultivars can be
categorized into participatory varietal selection and
participatory plant breeding (Witcombe et al., 1996).

In PVS, farmers select finished or nearly finished
products (released cultivars, varieties in advanced
stages of testing, and advanced non-segregating
lines) from plant breeding programs in their own
fields. In contrast, in PPB farmers select genotypes
from genetically variable, segregating materials.
PPB may be used when PVS has failed, or when
conventional plant breeding has not developed or
identified a variety suitable for a specific, usually
harsh, environment. The difference between PVS
and PPB may at first seem negligible, but PPB
requires more time and resources, while PVS
identifies materials that the seed sector can supply
more rapidly. Also, PVS and PPB have contrasting
impacts on biodiversity (Witcombe and Joshi, 1995;
Witcombe et al., 1996).

When scientists and farmers work together, they
learn from each other and begin to understand the
differences in their views and knowledge systems.
By bridging this gap, they are able to develop
solutions that respond to the perceived needs of

farmers. Solutions oriented towards fulfilling these
needs have greater potential for adoption and for
achieving positive changes in farming systems.

Farmers' role in varietal selection
Farmers are usually involved only in the final
stages of variety testing, generally after varieties
have been identified for release. On-farm
demonstrations and similar trials organized by
extension services are managed with the full range
of recommended external inputs, which can be
atypical of the predominant management practices
in the target region. Farmers have little or no input
regarding the management of these trials or the
varieties being tested. Farmers' evaluations of the
tested genotypes are usually not sought, nor are
their criteria applied, or if they are, they play little
or no role in the decision-making process for
varietal releases and recommendations (Farrington
and Martin, 1988). However, possibilities for
farmers' participation in selection are as diverse as
the nature of selection itself, e.g., selection among
single plants, progeny rows, experimental elite
lines or varieties, selection on-station, or selection
on their own farms (Weltzien et. al., 1998).

Farmer-Scientist Participatory Activities in
South Asia
For the last three crop seasons, the CIMMYT-South
Asia wheat regional program, in close partnership
with NARSs and other stakeholders working in the
region, has conducted PVS and PPB activities with
the following objectives:

* To promote the adoption and dissemination of new
varieties and site-specific resource conservation

* To obtain farmers' assessments of new improved
lines/varieties and specific traits
* To understand farmers' criteria in evaluating
improved germplasm
* To obtain feedback from farmers for breeding
* To demonstrate the value of combining improved
varieties with resource conservation techniques
In the 1998-99 season, 40 farmers from two villages
in the Varanasi area, State of Uttar Pradesh, were
invited to participate in the assessment of improved
wheat varieties/elite lines (including the old
popular variety HUW 234). During this PVS
exercise (jointly conducted with Banaras Hindu
University staff), the improved variety HUW 468
was identified by farmers.

In the 1999-2000 season, PVS activities were again
conducted in four farmers' fields in two villages
(Karhat and Baouli). The farmer-preferred variety
HUW 468 was compared with the old variety HUW
234 under conventional planting (broadcast
seeding) using the normal planting date (mid
November) and under zero tillage using a late
planting date (late December/early January). Field
days were organized to assess the preference of
farmers for the introduced technologies.

Under conventional planting/normal seeding date,
the variety HUW 468 yielded 15% more than HUW
234 (Figure 1) and maintained the same yield
advantage when the two varieties were planted
under zero tillage and late seeding date. Initially all
farmers had serious reservations about zero tillage,
but are now convinced of its advantages and
willing to buy their own drills.

Excess moisture delays planting in the area, and in
some years, no wheat is planted at all. By
combining the improved variety HUW 468 with
resource conservation technology, farmers in the
rice-wheat areas of eastern Uttar Pradesh can plant
their fields earlier, save on diesel, and increase their
yields. A large scale effort with the participation of
extensionists and NGOs working in the area is now
underway to help disseminate these technologies.

PVS exercises during the 1999-2000 season in other
villages in the area showed farmers' preference for
newly released varieties such as HUW 510 and HUW
516. Farmers indicated tillering ability as HUW 516's
most desirable trait. This information will help
accelerate seed multiplication of the two varieties.

HUW 234 is highly susceptible to diseases such as
helminthosporium leaf blotch and leaf rust. Thanks
to PVS activities, this variety may be replaced soon,
diversifying the spectrum of varieties grown in
farmers' fields.

PVS activities were conducted during 1999-2000 in
two contrasting regions of Nepal: Bankatti Village,
Rupandehi District in the Terai (lowlands), and
Kotounge Village, Bahtapur District in Kathmandu
Valley (mid-hills, 1000-1800 masl).

Bankatti Village, Rupandehi District, Bhairahawa
(Terai). The number of improved varieties grown in
farmers' fields is very high. The main varieties are
NL 297, Bhrikuti, UP 2338, Rohini, BL 1473, Achyut,
UP 262, BL 1022, and BL 1135. A PVS exercise was
conducted to determine the criteria used by farmers
in selecting wheat genotypes. Twenty farmers (men
and women) were invited to participate and divided
in two groups by gender. They were asked
individually to list traits they would like in a wheat
cultivar grown in their own farms, and to rank them.

S HUW 234 (Old)
5 HUW 468 (Improved)





Conventional under
normal planting

under late planting

Figure 1. Grain yield (kg/ha) of old vs improved wheat
varieties under conventional planting (Karhat Village) and
zero tillage (Baouli Village) in Varanasi, State of Uttar
Pradesh, India, 1999-2000.

Based on farmers' preferences, 12 wheat varieties
with contrasting differences for the identified traits
were planted in a replicated farmer-managed trial.
At physiological maturity, farmers in both gender
groups were asked to individually select wheat
genotypes based on their preferred traits and to list
the traits they preferred in the selected genotypes.

Women farmers gave priority to such traits as
disease and insect pest resistance (Table 3), and then
to chapati making quality and high grain yield.
Male farmers' top priorities were late heat stress
tolerance, large white grain, and shattering
tolerance. Chapati making quality was a low
priority for this group. The preferences of these two
groups may indicate the need for developing
varieties based on how they are used in the
household. Women farmers are usually in charge of
making bread and storing grain at home, while men
farmers are more concerned with "filling the sacks."

Both gender groups ranked recently released BL
1473 at the top (Table 4) due to its early maturity,
lodging tolerance, and bold, white grain. Based on
these results, NARC will speed up seed
multiplication of BL 1473. It will also take into
account farmers' feedback in planning crosses and
selecting populations in the breeding program.

Kotounge Village, Bahtapur District, Kathmandu
Valley (mid-hills). During the 1999-2000 season, a
PVS exercise was conducted in this village, located
at approximately 1500 masl (mid-hills). The main
wheat variety is the old, low yielding, and disease
susceptible variety RR-21 (=Sonalika).

Table 3. Ranking of farmer-preferred traits based on gender
criteria, Bankatti Village, Rupandehi District (Terai), Nepal,
Women: Men:
* Disease resistance Late heat stress tolerance
* Pest resistance Large, white grains
* Good chapati-making Shattering tolerance
* High yield Disease resistance
* High tillering Lodging tolerance
* Medium height Early maturity
* White-bold seed High yield
* Lodging tolerance Medium height
*Large spikes Good chapati-making
*Shattering resistance
*Short awns

A set of 10 improved wheat lines and/or varieties
was grown in a farmer-managed trial. A parti-
cipatory field day was organized at physiological
maturity to allow farmers to quantitatively assess
the cultivars. Thirty farmers (men and women)
ranked the wheat variety BL-1473 as the top
performer in that set of genotypes. Farmers
preferred the variety due to its early maturity, bold
seed, good straw yield, high fertility, and lodging
tolerance. BL-1473 yielded 30% more grain than

Based on these results, about 1.2 t of foundation
seed of BL-1473 were distributed to 60 farmers a
few days before the 2000-2001 crop season began.
We are optimistic that RR-21 will shortly be
replaced by the new variety.

Results of a survey conducted a few days before
the PVS exercise began showed that the ratio of
new, improved vs old varieties (mainly disease
susceptible RR-21) in the area was 10% to 90%. We
are optimistic that this ratio will be reversed in
2001-02 and that the new variety will be adopted
by farmers in the mid-hills, since 95% of seed
dissemination occurs from farmer to farmer.

Lack of improved varieties, poor technology
transfer, and a deficient seed multiplication system
are mainly responsible for low wheat productivity
in the northern hill region of Pakistan. Ten wheat
varieties and elite lines developed by NARC's
NWRP and the Turkey / CIMMYT / ICARDA Winter

Table 4. Ranking of farmer-preferred varieties based on
gender criteria, Bankatti Village, Rupandehi District, Nepal,
Women: Men:
* BL1473 BL1473
* Nepal 297 NL 731 and NL 297
* NL731 Bhrikuti
* BL1724 BL1724 and BL1692
* Bhrikuti NL753

and Facultative Wheat Program were grown in
1999-2000 in 10 farmers' fields in northern Pakistan
(1400-2800 masl).

At physiological maturity, 60 farmers
quantitatively assessed a set of those cultivars in
Sultanabad, Gilgit District. When asked to rank
their preferred cultivars and list the reasons for
selecting them, farmers consistently indicated
three lines (in ranking order):

1. 951352 Zander (=1WWEERYT # 128)
2. 980815 8023.16.1.1/Kauz (=AYT # 9086)
3. 951273 VORONA/HD2402 (=EYT # 9818)
The farmers' main reasons for choosing these lines
were earliness, good straw, good head size, good
lodging resistance, and bold white seed. The top
three cultivars yielded 30-40% more than Suneen,
the local variety (Table 5). Farmers like Suneen due
to its straw yield, yet two farmer-preferred lines
produced 5-6% more straw than Suneen.

The best varieties will be multiplied more
extensively in 2000-01 to obtain enough seed to
distribute to as many farmers as possible. Since
most seed dissemination occurs from farmer to
farmer, a large area should be sown to those
varieties in 2-3 years.

Special thanks to the many farmers who
participated and provided their valuable
experience and feedback during these PVS
activities. We also thank the National Wheat
Research Program of NARC Pakistan and the
Turkey / CIMMYT / ICARDA Wheat Program for
providing elite wheat germplasm for PVS activities
in northern Pakistan.

Farrington, J., and Martin, A. 1988. Farmer participation in agricultural research: A
review of concepts and practices. Agricultural Administration Unit. Occasional Paper
9. London, UK: Overseas Development Institute.
Pingali, PL. (ed). 1999. CIMMYT 1998-99 World Wheat Facts and Trends. Global
Wheat Research in a Changing World: Challenges and Achievements. Mexico, D.F.:
Rosegrant, M.W., Agcaoli-Sombilla, M., and Perez, N.D. 1995. Global food
projections to 2020: Implications for investment. Food, Agriculture, and the
Environment Discussion Paper 5. Washington, D.C.: International Food Policy
Research Institute.
Weltzien, R.E., Whitaker, M.L., Rattunde, H.F.W., Dhamotharan, M., and Anders,
M.M. 1998. Participatory Approaches in Pearl Millet Breeding. In: Seeds of
Choice, Making the Most of New Varieties for Small Farmers. Witcombe, J.R.,
Virk, S.V. and Farrington, J. (eds.). pp. 1-271.
Witcombe, J.R., and Joshi, A. 1995. The impact of farmer participatory research on
biodiversity of crops. In: Using diversity-enhancing and maintaining genetic
resources on-farm. Proceedings of a workshop held on 19-21 June 1995, New
Delhi. Sperling, L. and Loevinsohn, M.L. (eds.). New Delhi, India: International
Development Research Center. pp. 87-101.
Witcombe, J.R., Joshi, A., Joshi, K.D., and Sthapit, B.R. 1996. Farmer Participatory
Crop Improvement. I. Varietal Selection and Breeding Methods and Their Impact
on Biodiversity. Expl. Agric. 32:445-460.

Table 5. Farmer-preferred wheat cultivars and their actual grain and straw yield, PVS Trial, Sultanabad Village,
Northern Pakistan, 1999-2000.
Farmer-preferred cultivar
(in ranking order) Grain yield (kg/ha) % of local cv Straw yield (kg/ha) % of local cv
951352 Zander 3808 140 5712 105
980815 8023.16.1.1/Kauz 3536 130 5768 106
951273 Vorona/HD 2402 3536 130 5440 100
Suneen (local cultivar) 2720 100 5440 100

Global Monitoring of Wheat Rusts, and

Assessment of Genetic Diversity and

Vulnerability of Popular Cultivars

R.P. Singh and J. Huerta-Espino

There are more than 40 diseases and insects that
can cause economic losses to the wheat crop under
various conditions. However, the greatest danger
worldwide, in terms of severe crop losses, is the
regional rust epidemics that can arise as a result of
an attack by any of three airborne pathogens, i.e.,
Puccinia graminis tritici, Puccinia triticina, and
Puccinia striiformis, that cause stem (black) rust, leaf
(brown) rust, and stripe (yellow) rust diseases of
wheat, respectively.

Why Monitor Rust Pathogens?
The most environmentally and farmer friendly
strategy for reducing yield losses is the use of rust
resistant cultivars. Resistances based on single,
major, race-specific genes often become ineffective
within five years of their deployment, producing
"boom and bust" cycles in wheat production. The
"bust" cycles (when rust resistance has been
overcome) are caused either by pathogens
mutating to acquire virulence, a virulent race
migrating into a new region, or sexual and asexual
recombination in the
pathogen. Early detection
of new virulences in
pathogen populations
makes it possible to replace
susceptible cultivars with 9
resistant cultivars in time to 9 19
avoid large-scale

Rust pathogens migrate
from one region to another 198
by wind movement. For
example, virulence in P.
striiformis for the Yr9 gene Fiaure 1. Movement of Yi

evolved in East Africa and recently migrated to
North Africa, West Asia, and South Asia all the
way to Nepal (Figure 1). On the way, this Yr9 race
caused major epidemics in Ethiopia, Turkey, Iran,
Afghanistan, and Pakistan. Concerted pathogen
monitoring efforts, combined with knowledge of
genetic resistance in cultivars and the
governments' willingness to take prompt action,
could have avoided or reduced the losses.

Important cultivars whose resistance is based on a
single race-specific gene, or combinations of a few
of them, are currently grown over large areas in
countries where yellow rust has caused major
losses or posed serious threats in the past few
years. Inquilab 91 (resistance based on Yr27) and
PBW343 (resistance based on a Yr3 / Yr9
combination), the most important cultivars in
northwestern Pakistan and India, respectively, are
highly vulnerable. Virulences for Yr27, Yr3, and
Yr9, and their combinations, are known to occur
outside the region, viz. Mexico.

9 virulence.

Inquilab 91 and PBW343 showed unacceptably low
levels of adult plant resistance in Mexico when
tested with a race virulent to the above genes.
Similarly, a number of Kauz-derived varieties, e.g.
Bakhtawar 94 (Pakistan), WH542 (India), Memof
(Syria), Basribey 95 and Seyhan 95 (Turkey), and
Atrak (Iran), were released following widespread
epidemics in those countries on cultivars derived
from Veery#5. The immunity of Kauz in these
countries is due to the combination of Yr9 and
Yr27. Combined virulences for these two genes in
the yellow rust population does not exist at present
in the above countries; however, they are known to
occur in Mexico. Slow rusting gene Yr18, also
present in Kauz, does not by itself confer enough
protection under high disease pressure (Ma and
Singh, 19961); hence Kauz shows unacceptable
disease levels when tested in Mexico.

This type of information on the genetic basis of
resistance would be extremely useful for a country
preparing for a potential epidemic and trying to
diversify the crop by promoting genetically diverse

CIMMYT's External Program and Management
Review panel in 1997 made a strong
recommendation to the Wheat Program to
reinitiate monitoring of changes in virulence of the
rust pathogens. This could have avoided the large-
scale epidemic of yellow rust that occurred
recently. This recommendation was later endorsed
by the Technical Advisory Committee of the

Breeding for rust resistance at CIMMYT, which
began in the late 1960s and early 1970s, has moved
a long way away from the use of major, race-
specific genes and currently focuses on
combinations of minor, slow rusting genes that
impart durability of resistance. However, all
cultivars currently grown in developing countries
are not likely to possess such resistance. Until a
majority of cultivars carry durable resistance, as is
the case for stem rust, monitoring the rust

pathogens and simultaneously evaluating the type
of resistance in the main cultivars are considered
essential for avoiding losses. Leaf and yellow rusts,
of high to moderate importance in all wheat
growing regions, will be the focal diseases. Stem
rust is currently considered important in Africa
and parts of the Southern Cone of South America.

In the 1980s CIMMYT established collaborative
arrangements with the Cereal Rust Laboratory, St.
Paul, Minnesota, and IPO, Wageningen, the
Netherlands, where samples of rusts for virulence
analysis could be sent from anywhere in the world.
However, such arrangements have no longer been
possible following the retirement of key scientists
in the above labs. After some discussion, the
decision was made at CIMMYT to promote the
establishment of Regional Monitoring Nurseries.

Epidemiological Regions for Monitoring
In developing countries wheat is grown in six
epidemiological regions that are not necessarily
fully isolated (Table 1). Though rusts can cross
boundaries between these regions, this may take
more time than moving within a given region,
where movement is less restricted. Eastern and
Southern Africa may well be separate regions;
however, due to the recent introduction of yellow
rust into South Africa and to increased human
migration between the two regions, the African
NARSs have decided to grow a common
monitoring nursery.

Table 1. The six regions participating in the monitoring of rust
Region Rusts
Indian Subcontinent Leaf rust, yellow rust
China Leaf rust, yellow rust
West Asia and North Africa1 Leaf rust, yellow rust
Eastern and Southern Africa Stem rust, leaf rust, yellow rust
Central Asia Yellow rust, leaf rust
Southern Cone of South America Leaf rust, yellow rust
1 In collaboration with ICARDA.

1 Ma, H., and R.P. Singh. 1996. Contribution of adult plant resistance gene Yr18 in protecting wheat from yellow rust. Plant
Dis 80:66-69.

Monitoring nurseries
The nurseries have a group of common entries:
near-isogenic lines for the named Lr and Yr genes,
a group of cultivars carrying known gene
combinations, and a group of cultivars/lines of
international significance (Table 2). Seeds of these
lines were shipped to CIMMYT's outreach
programs or designated NARSs for increase during
the 1999 and 1999-2000 crop seasons. A set of
important cultivars grown in each of the regions
forms the supplementary regional set. Regional
nurseries are being grown (beginning in the 2000-
2001 crop season) at carefully selected key sites in
each region and a few selected hotspots outside the
region. This will enable us to put regional
information into a global context.

Data collection and analysis
Each entry will be evaluated for disease severity
and reaction by the NARS at each site where

Table 2. Structure of rust monitoring nurseries.
Type of entry Number
Near-isogenic lines for Lr genes 39
Durum wheats 5
Cultivars with known combinations of tr genes 13
Cultivars with slow rusting resistance to LR and YR 12
Highly susceptible cultivar Morocco 1
Near-isogenic lines for Yr genes 15
Important cultivars grown in the region 20 to 40 entries
Single gene lines for Sr genes (only in Africa) about 40 entries

disease occurs. Otherwise, the lack of disease will
be recorded. Rust samples will be collected for
pathogenicity (virulence/ avirulence) analysis and
shall be sent to a designated laboratory in regions
where such facilities exist (Table 3). In regions
where there are such facilities in some countries
but not in others, we are trying to negotiate
agreements whereby countries that have facilities
will provide support to those that do not. Whether
we will succeed remains to be seen. Quarantine
regulations are the greatest barrier to moving
diseased samples between countries. Leaf and stem
rust samples of high importance could be analyzed
at the Cereal Disease Laboratory in St. Paul,
Minnesota, by J. Kolmer.

Race-specific genes present in regional cultivars
will be postulated and the level of minor genes-
based slow rusting resistance assessed, where
possible. This work will be done in Mexico by
CIMMYT and by C. Wellings at the University of

Information on virulence in pathogen populations,
race-specific resistance genes, and the presence of
slow rusting resistance in the cultivars will be
utilized to determine the probable genetic
vulnerability and risk of continuing to cultivate
specific cultivars in particular regions. This
information will be shared on a regular basis with
NARS scientists and decision makers in each

Table 3. Regional scientists and laboratories collaborating in race identification.
Region Regional Rust Laboratory Pathogen
Indian Subcontinent S.K. Nayar, DWR Regional Station, Flowerdale, Shimla, India Leaf rust, Yellow rust
China W.Q. Chen, Institute of Plant Protection, CAAS, Beijing, China Leaf rust, Yellow rust
West Asia and North Africa M. Torabi, SPII, Karaj, Iran Yellow rust
Eastern and Southern Africa C. le Roux, SGI, Bethlehem RSA Stem rust, Leaf rust, Yellow rust
Central Asia ?
Southern Cone of South America A. Barcellos, Embrapa Trigo, Passo Fundo, Brazil Leaf rust, Stem rust
S. German, INIA, Colonia, Uruguay Leaf rust

Marker-Assisted Selection for

BYDV Resistance in Wheat

M. Henry, M. van Ginkel, and M. Khairallah

Barley yellow dwarf (BYD) is the most important
viral disease of cereals. It has a worldwide
distribution and infects a wide range of gramineae,
including the major cereal crops. The disease is
caused by five insect-transmitted luteoviruses,
collectively known as barley yellow dwarf virus.
The serotypes are PAV, MAV, RPV, RMV, and SGV
(Waterhouse et al., 1988). PAV is the most severe and
most common serotype, followed in occurrence by
MAV and RPV.

Control of the disease can be partially achieved
through the application of insecticides, cultural
practices (such as changes in sowing date, alternate
cropping, and removal of virus reservoirs), and the
use of germplasm with tolerance or resistance to the
virus or its vectors. In the sense of Cooper and Jones
(1983), tolerant lines present attenuated symptoms
and lower yield losses even though they multiply
the virus. In resistant lines, virus multiplication and
spread are inhibited or reduced, which may or may
not attenuate symptoms. Tolerance to BYD in bread
wheat has been reviewed by Burnett et al. (1995).
Though not present in bread wheat, true resistance
has been identified in several wheat relatives, such
as Thinopyrum intermedium. Banks et al. (1995)
successfully transferred this alien-derived resistance
to bread wheat and produced a series of
translocated lines (so-called TC lines) using tissue

Previous observations showed that lines in the TC14
group had the most potential for wheat breeding
because they showed low virus concentrations after
infection with BYDV-PAV, -MAV, or -RPV (Henry,
1997) and carried the smallest translocation
(Hohmann et al., 1996). However, though resistant,
these lines were poorly adapted to the Mexican
environment and sensitive to the infection; they

would thus exhibit severe symptoms in the field
when infected (Henry, 1997). In light of these
findings and to achieve better BYDV control, our
strategy has been to combine the alien-derived
resistance with tolerance in good agronomic

Resistance induced by the Th. intermedium
translocation was found to be associated with a
reduction in virus titers of BYDV-PAV under field
and greenhouse conditions and a lower infection
rate when artificially inoculated with BYDV-PAV or
MAV in the field (Ayala et al., 2001). A reduction in
virus titers was also observed with BYDV-MAV and
RPV under greenhouse conditions (Henry,
unpublished data).

At CIMMYT, screening for BYD has been based
mainly on observation of symptoms after natural or
artificial inoculation and has focused on identifying
tolerance to the disease. Screening for resistance is
laborious, involving artificial inoculation in the field
or greenhouse and measuring virus titers by ELISA
(enzyme-linked immunosorbent assay); to combine
resistance with tolerance, lines are screened for low
symptoms under infection. To complicate matter
even more, expression of tolerance and resistance is
strongly influenced by environmental conditions.

To overcome some of the constraints of testing for
BYD tolerance and resistance, a search for molecular
markers for these traits was undertaken. An SSR
(simple sequence repeat) marker, gwm37, identified
by Ayala et al. (2001), shows polymorphism between
resistant TC14 lines and bread wheat. It is a
diagnostic co-dominant marker that differentiates
individuals possessing the Th. intermedium
introgression (Ti) in homozygocity or heterozygocity
from those not carrying it. Tolerance proved to be

controlled by several QTLs with small effects, for
which no diagnostic markers could be identified
(Ayala et al., unpublished data). In this paper, we
report the use of gwm37 in a marker-assisted
selection strategy to incorporate Th. intermedium-
derived resistance into high yielding bread wheats.
The strategy involved selecting tolerant progeny
for BYD resistance as a way of overcoming some of
the limitations of the resistant but sensitive TC14

Materials and Methods
Selection strategies
Resistant lines TC14/2*Spear and TC14/2*Hartog
(CSIRO 289B, 289X), kindly provided by Philip
Banks, CSIRO, Australia, were crossed to about 50
advanced CIMMYT wheats representing materials
adapted to irrigated, high rainfall, and/or drought
environments. The materials were shuttled
between a coastal irrigated site, Cd. Obregon in
northwestern Mexico, and a high rainfall location
near Toluca, in the central highlands of Mexico.
Diseases prevalent in the two sites are different,
and include leaf, stripe, and stem rusts, Septoria
tritici, fusarium head blight, and a complex of soil-
borne diseases. The best F2 plants within a cross
were harvested in bulk. Selection criteria included
good agronomic type, durable disease resistance,
synchronous tillering, desired spike type and size,
good fertility, appropriate height and maturity, as
well as well-filled grains. Within the F3 and F5
plots, the best plants were selected, harvested,
threshed in bulk, and visually checked for grain

In the F4 and F6 generations, individual plants or
lines were grown in Toluca under high natural
disease pressure. They also underwent selection
with artificial BYDV-PAV (Mexican isolate)
inoculation in El BatAn, also in the central Mexican
highlands. Outstanding plants were visually
selected at heading based on reduced or no BYD
symptoms. The presence of the introgression
(resistance allele) was then assessed using the SSR
molecular marker gwm37. Resistant plants or lines
were confirmed by measuring virus titers using

BYDV testing
BYDV testing was carried out during the summer
cycle at CIMMYT, El Batan, Mexico, in June 1999
and 2000. Seedlings were inoculated at the 3-leaf
stage (Zadoks'13, Zadoks et al., 1974). The F4s were
space planted in a 4 x 5 m plot with double rows,
while the F6s were sown in paired 1-meter double
plots, one being infected and the other kept free of
aphids through regular insecticide application.

ELISA (enzyme-linked
immunosorbent assay)
Double antibody sandwich ELISA (DAS ELISA)
was used as described by Ayala et al. (2001).
Optical density (OD) was measured at 405 hm
using a MR 700 Microplate reader (Dynatech
Laboratories). A plant was considered infected
when the OD was higher than twice the OD of the
non-infected control. ELISA values were classified
as follows: Low: OD<0.25, Moderate: 0.25 High: OD>0.4. In testing the F4s, the average OD
value obtained for the resistant TC14/2*Spear was

Determining the presence of the
The presence of the translocation was assessed
using the SSR marker as described in Ayala et al.
(2001). Plants or lines were classified as
homozygous resistant (TiTi), susceptible (titi) or
heterozygous (Titi).

Results and Discussion
Four of the sixteen populations advanced to F4
were discarded after field evaluation in Toluca
because of their high sensitivity to yellow rust. In
El Batan, from the 12 remaining populations, 479
plants were selected based on their good
appearance after BYDV inoculation. This group
included plants not presenting any BYD-like
symptoms and appeared to have escaped infection.
As reported previously, this characteristic is also
associated with Th. intermedium resistance (Ayala et
al., 2001; Henry and Segura, 1999).

The range of OD values obtained in the selected
lines with low symptoms levels was high (0.079-
1.158), indicating that some plants were good hosts
for the virus without presenting severe symptoms
and thus could be qualified as tolerant.

PCR analysis was completed on 403 of the 479
plants selected. Of those, 34.5% were homozygous
for the translocation (TiTi), 17.4% heterozygous
(Titi) and 48.1% did not carry the fragment at all

A high proportion of the non-infected lines were
either homozygous or heterozygous for the Th.
intermedium fragment confirming the effect of the
translocation on the incidence of infection (Table 1).
Though the virus titers were distributed in three
classes (low, medium or high), there was a
tendency for the homozygous lines (TiTi) to have
low or medium ODs, while the lines without the
translocation (titi) had virus titers in the medium
or higher classes.

Lines with reduced symptoms, low virus titers, or
no infection, and shown to be homozygous for the
translocation were selected and advanced to the F5.
In total 156 lines were selected and tested for good
agronomic characteristics in Obregon. Fifty-eight
lines were advanced to the F6. In the F6, 10 were
finally selected as having BYDV resistance
homozygouss for the translocation, low virus titers)
and some level of tolerance. Their resistance/
tolerance will be re-evaluated for an additional

In Toluca, selection among F4 populations was
based on good agronomic characteristics, resistance

Table 1. Distribution of selected F4 individuals among
genotypic groups (based on gwm37) and classes of virus
titers under BYDV pressure in El Batan.
Percentage of individuals
Homo- Hetero- No
zygous zygous translocation Missing
Virus titer (TiTi) (Titi) (titi) data
Not infected 28.8 8.6 2.6 4.0
Low 41.7 37.1 27.3 37.3
Medium 21.6 42.9 40.2 37.3
High 7.9 11.4 29.9 21.3

to stripe rust, and some level of BYDV tolerance.
One hundred and ninety-six plants were selected
from the 12 crosses mentioned above. The
distribution of selected plants in the three
genotypic groups was different from the one
obtained in El BatAn. There was a higher
proportion of heterozygous individuals in Toluca
(41.8%) than in El BatAn (14.8%), and a lower
proportion of individuals not carrying the
translocation in Toluca (9.7%) than in El BatAn
(40.5%). This indicates that during initial selection
for BYD tolerance, a high proportion of plants not
carrying the translocation were chosen, possibly
because the translocation is not associated with

A total of 177 plants (missing data, TiTi, and Titi)
selected in Toluca were advanced to the F5. Forty
lines were tested as F6s and nine were finally
selected as carrying both resistance and tolerance
to BYDV.

The data suggest that selection based on the
presence of the translocation as detected with the
molecular marker gwm37 can be used in early
generations, thus avoiding the need for special
field screening. This should be followed by one or
two cycles of testing under BYDV infection and
estimation of virus titers to make sure resistance is
still expressed. Final evaluation of true resistance
as expressed in reduced virus titers can also be
done in the greenhouse. However, to combine
resistance and tolerance, screening under BYD
pressure is recommended at least every other cycle.
In addition, because our task at CIMMYT is to
provide germplasm adapted to different

Table 2. Distribution of selected F4 individuals in three
genotypic groups (based on gwm37) under selection with (El
Batan) or without BYDV pressure (Toluca).

Genotypic groups
Homozygous resistant (TiTi)
Heterozygous (Titi)
Homozygous susceptible (titi)
Missing data

Percentage of individuals
El Batan Toluca
29.0 17.3
14.8 41.8
40.5 9.7
15.7 31.1

environments with strong disease pressure, in
particular rusts, it is important to alternate
screening under BYD pressure with other
diseases, such as leaf and stem rusts (Cd.
Obregon) and yellow rust (Toluca).

We have obtained a set of 19 lines (Table 3)
combining BYDV resistance and (apparently) a
certain level of tolerance. Tolerance to BYD in
wheat is polygenic in nature, based on the action
of minor genes. It is more important to have
uniform infection when selecting for minor gene
resistance than for major gene resistance
(Qualset, 1984). In crosses with Th. intermedium-
derived material, escape from infection is more
common than in susceptible wheat, resulting in
non-uniform infection. A sensitive plant might be
rated as tolerant if it did not get infected. To
minimize the error due to the escape mechanism
and because BYD expression is strongly
associated with the environment, it is important
to confirm the tolerance identified in this work
through another cycle of testing.

The molecular marker gwm37 has proven to be a
reliable tool for incorporating BYDV resistance,
accelerating the process, and reducing the need

for continuous testing under BYDV infection. This
marker has been used successfully in selecting
other populations, such as backcrosses with
tolerant BYD germplasm.

Table 3. List of F6 lines carrying both resistance and tolerance to


Selection history


CMSS97M00087S-030M-020Y-1 OBYB-01 OY
CMSS97M00087S-030M-020Y-11 M-01 OY
CMSS97M00087S-030M-020Y-13BYB-01 OY
CMSS97M00087S-030M-020Y-17M-01 OY
CMSS97M00115S-030M-020Y-16BYB-01 OY
CMSS97M00151 S-030M-020Y-1 M-01 OY

Ayala, L., Khairallah, M., Gonzalez-de-Leon, D., van Ginkel, M., Mujeeb-Kazi, A.,
Keller, B., and Henry, M. 2001. Identification and use of molecular markers to
detect barley yellow dwarf virus resistance derived from Th. intermedium in bread
wheat. Theoretical and Applied Genetics (in press).
Banks, PM., Larkin, P.J., Bariana, H.S., Lagudah, E.S., Appels, R., Waterhouse, PM.,
Brettell, R.I.S., Chen, X., Xu, H.J., Xin, Z.Y., Qian, Y.T., Zhou, X.M., Cheng, Z.M.,
and Zhou, G.H. 1995. The use of cell culture for subchromosomal introgressions
of barley yellow dwarf virus resistance from Thinopyrum intermedium to wheat.
Genome 38:395-405.
Burnett PA., Comeau, A., and Qualset, C.O. 1995. Host plant tolerance or resistance
for control of barley yellow dwarf. In: Barleyyellow dwarf: 40 years of progress.
D'Arcy, C.J., Burnett, PA. (eds.). St. Paul, MN, USA: APS Press. pp. 321-343.
Cooper, J.I., and Jones, A.T. 1983. Responses of plants to viruses: Proposals for the
use of terms. Phytopathology 73:127-128.

Henry, M. 1997. Evaluation of resistance to BYDV in Thinopyrum intermedium
translocated lines. In: Barley Yellow Dwarf Newsletter. No. 6. Henry, M. (ed.).
Mexico, D.F.: CIMMYT. p 8.
Henry, M., and Segura, J. 1999. Estimation of yield losses due to BYDV in wheat
under artificial inoculation. Phytopathology 89:S33.
Hohmann, U., Badaeva, K., Bush, W., Friebe, B., and Gill, B.S. 1996. Molecular
cytogenetic analysis of Agropyron chromatin specifying resistance to barley yellow
dwarf virus in wheat. Genome 39:336-347.
Qualset, C.O. 1984. Evaluation and breeding methods for barley yellow dwarf
resistance. In: Barley Yellow Dwarf. A Proceedings of the Workshop. P Burnett
(ed.). Mexico, D.F.: CIMMYT. pp. 72-82.
Waterhouse, PM., Gildow, F.E., and Johnstone, G.R. 1988. Luteovirus group. C.M.I./
A.A.B. Description of plant viruses 339.
Zadoks, J.C., Chang, T.T., and Konzak, C.F 1974. A decimal code for the growth
stages of cereals. Weed Research 14:415-421.

Durable Resistance to

Yellow (Stripe) Rust in Wheat

R.P. Singh, S. Rajaram, J. Huerta-Espino, and M. William

Yellow (or stripe) rust, caused by Puccinia
striiformis tritici, is an important disease of wheat in
most cool wheat-producing regions. Using resistant
cultivars is the best disease control strategy, since it
comes at no extra cost to the farmer and is
environmentally safe. Historically, race-specific
major genes have been used to breed rust resistant
wheat cultivars. At present 30 resistance genes
have been catalogued (McIntosh et al., 1998). Most
are race-specific in nature, and virulence for several
of them has been identified somewhere in the
world. One of the main objectives of CIMMYT's
wheat improvement program is to generate
genetically diverse germplasm that has high yield
potential, wide adaptation, and durable resistance
to important diseases such as the rusts.

Durable resistance as defined by Johnson (1978) is
one that has remained effective in a cultivar during
its widespread cultivation for a long sequence of
generations or period of time in an environment
favorable to a disease or pest. Johnson (1978; 1988)
described the presence of durable resistance in
some European wheat cultivars and indicated that
such resistance is quantitative in nature. The
moderate level of adult plant resistance of
CIMMYT-derived North American cultivar 'Anza'
and good level of resistance in Mexican cultivar
'Pavon 76' have shown durability (Rajaram et al.,
1988). During the early 1990s research was initiated
to identify CIMMYT wheats that may carry
durable resistance, understand the genetic basis of
such resistance, and develop selection strategies to
breed such resistance in newer CIMMYT wheats.
Key knowledge developed during the last decade
of research is summarized here.

Yrl8 and other minor genes for durable
resistance to stripe rust
Independent results obtained by Singh (1992) and
McIntosh (1992) indicated that the moderate level
of durable adult plant resistance in Anza and
winter wheats such as Bezostaja is controlled in
part by the Yr18 gene. Gene Yrl8 is completely
linked with gene Lr34, known to confer durable leaf
rust resistance. The level of resistance it confers is
usually not adequate when present alone. However,
combinations of Yrl8 and 2-4 additional slow
rusting genes result in adequate resistance levels in
most environments (Singh and Rajaram, 1994).
Results of genetic analyses indicate that the level of
resistance increases with the increase in the number
of these genes that individually have minor to
intermediate but additive effects. Cultivars carrying
such Yr18 complexes are listed in Table 1.

Genes Lr34 and Yrl8 occur frequently in
germplasm developed at CIMMYT and in various
other countries. Using Jupateco 73 near-isogenic

Table 1. Seedling susceptible bread wheats that carry good
adult plant resistance to stripe rust in field trials in Mexico
and other countries.
Usual yellow Additive for
Genotype(s) rust response1 genes2 resistance
Jupateco 73S (check) 100 MS Moderately susceptible
Jupateco 73R 50 M Yr18
Parula, Cook, Trap 15 M Yr18+ 2 genes
Tonichi 81, Sonoita 81, Yaco 10 M Yr18 + 2 or 3 genes
Chapio, Tukuru, Kukuna, Vivitsi 1 M Yr18 + 3 or 4 genes
Amadina 30 M 3 genes
Pavon 76, Attila 20 M 3 genes
S The yellow rust response data from Mexico have two components: % severity based
on the modified Cobb scale (Peterson et al., 1948) and reaction based on Roelfs et al.
(1992). The reactions are M = moderately resistant to moderately susceptible,
sporulating stripes with necrosis and chlorosis; and S = sporulating stripes without
chlorosis or necrosis.
2 Minimum number estimated from genetic analysis.

reselections, studies at CIMMYT have shown that
gene Yrl8 increases latent period and decreases
infection frequency and length of infection lesions
(stripes) in greenhouse experiments inoculated
with yellow rust (Table 2). This indicates that
components of slow rusting associated with Yrl8
are under pleiotropic genetic control. Diversity for
minor genes is quite high; almost all of the more
than 300 released cultivars studied by us have
shown the presence of small to moderate and,
occasionally, high levels of adult plant resistance.

Intercrosses among wheats listed in Table 1 have
shown that although Yr18 is a frequently occurring
resistance gene, at least 10 to 12 additional slow
rusting genes that have minor to intermediate
effects are present in the wheat lines studied.
Transgressive segregation leading to resistance
levels superior to those of the parents was common
in all intercrosses of the resistant parents. Cultivars
such as Pavon 76 and Attila do not carry Lr34 but
possess other minor genes that confer adult plant

Because it can develop systemically, stripe rust is
different from the other two rusts, where every
new pustule develops from a new infection. The
epidemiology of stripe rust is also different from
that of the other two rusts. Johnson (1988)
presented examples of adult plant resistance genes
that are race-specific in nature. It is difficult to
distinguish such resistance from the resistance
conferred by genes of race-nonspecific nature,
based on the adult plant infection type. Low
disease severity to stripe rust is most often
associated with at least some reduction in infection
type. However, we have observed that in the case
of potentially durable slow rusting resistance, the

Table 2. Comparison of three components of slow rusting
resistance to stripe rust in seedling and flag leaves of near-
isogenic Yrl8 Jupateco 73 reselections tested at 15 oC.
Infection Length of
Latent period frequency stripes
Genotype (days) (stripes/cm2) (mm)
Jupateco+ Yr18 20.1 0.7 12.5
Jupateco -Yr18 15.9 7.1 47.7

first uredinia to appear are moderately susceptible
to susceptible. Subsequent growth of fungal
mycelium causes some chlorosis and necrosis;
therefore, the final infection type is usually rated as
moderately resistant-moderately susceptible.
Durability of such resistance can be expected if the
cultivar's low disease severity is due to the additive
interaction of several (4 to 5) partially effective

Genetic linkage/pleiotropism of
resistance genes
Genetic linkage between slow rusting genes Lr34
and Yrl8 was mentioned above. Our recent results
show that durable stem rust resistance gene Sr2 is
closely linked to minor gene Yr30 conferring yellow
rust resistance (Singh et al., 2000b). Quantitative
trait locus (QTL) analysis of slow rusting resistance
to leaf and yellow rusts in two recombinant inbred
populations at CIMMYT has shown that several
QTLs conferred resistance to both these rusts (Table
3). As shown in Table 3, disease-specific QTLs were
also present for both leaf and yellow rusts,
indicating that close genetic linkage or pleiotropism
is not a rule. Slow rusting leaf rust resistance gene
Lr46 was linked to a gene for slow rusting yellow
rust resistance, recently designated by us as Yr29.
Functional aspects of slow rusting genes will be
better understood once the genes are cloned.
Because the same, or closely linked, minor, slow

Table 3. QTLs for slow rusting, additive genes involved in
resistance to leaf and yellow rusts of wheat mapped by
evaluating RILs from crosses of susceptible wheat 'Avocet S'
and resistant 'Pavon 76' and 'Parula' for three years at field
sites in Mexico.
Disease severity reduction (%)
Cultivar Location Marker Leaf rust Yellow rust Named genes
Pavon 76 1BL Wms259 35 27 Lr46, Yr29
4B Wms495 18 15
6A Wms356 14 18
6B PaggMcaa 18
3BS PacgMcgt 11 Yr30, Sr2
Parula 7DS Ltn1 56 46 Lr34, Yr18
7Bor7D Pcr156 29
1BL Wms259 15 16 Lr46, Yr29
Unknown PaagMcta 22 14
3BS Glk2 12 Yr30, Sr2
1 Leaf tip necrosis, a morphological marker linked to gene lr34.

rusting genes confer resistance to more than one
rust disease, generating multiple rust resistance
germplasm should be simpler than is usually

Selecting for resistance based on
additive minor genes
It is often believed that selecting for resistance
based on additive interactions of minor genes is
difficult. However, at CIMMYT the following steps
aimed at enhancing the accumulation of such
genes are being taken:

* Selecting parents that lack effective major genes
and have moderate to good levels of slow rusting
resistance to local rust pathotypes. Such parents
are easily identified by testing them at the seedling
stage in the greenhouse and as adult plants in the
field using the same pathotype. Parents of interest
should show susceptibility as seedlings and slow
rusting as adult plants in the field. Known
cultivars with durable resistance are also included.
* Maintaining genetic diversity. Based on available
information, parents having different sets of
additive genes are used in crossing. If such
information is not available, parents of diverse
origins or diverse pedigrees are selected for
* Establishing high disease pressure in the breeding
nursery with chosen rust pathotypes. Spreader
rows are planted at optimum distance and
artificially inoculated to ensure homogeneous
disease spread of desired rust pathotypes in
breeding plots. Susceptible and slow rusting
checks are included to assess disease pressure.
* Selecting plants with low to moderate terminal
disease severity in F2 and F3, and from F4 onwards
selection of plants or lines with low terminal
severity. Because adequate resistance levels require
the presence of 3 to 5 additive genes, the level of
homozygosity from the F4 generation onwards is
usually sufficient to identify plants or lines that
combine adequate resistance with good agronomic
features. Moreover, selecting plants with low
terminal disease severity under high disease
pressure means that more additive genes may be
present in those plants.

* Maintaining leaf tip necrosis or mild pseudo-black
chaff phenotypes. Because leaf tip necrosis is
linked with durable resistance genes Lr34 and
Yr18, and pseudo black chaff is linked with Sr2,
these traits are useful morphological markers.
* Conducting multilocational testing. As discussed
earlier, multilocational testing of useful advanced
lines can indicate the effectiveness and stability of
resistance across environments. Based on the
results, new lines are identified for future crossing.
* Genetically analyzing selected lines to confirm the
presence of resistance based on additive genes.
Following the methodology described above, we
have successfully combined high levels of
resistance (comparable to near-immunity) to leaf
and yellow rusts with high grain yield potential in
wheat lines such as Chapio, Tukuru, Kukuna, and
Vivitsi (Table 1) (Singh et al., 2000a). Genetic
analysis of such resistance has shown that at least 4
or 5 minor, additive genes confer resistance to both
leaf and yellow rusts. These wheat lines can be
released directly for cultivation or can be used in
future breeding programs.

A Challenge for the Next Decade
The challenge in the next decade will be to release
several durably resistant cultivars and convince
farmers to adopt them. The level of adult plant
resistance in these cultivars must be adequate to
meet the stringent requirements for release set in
each country and to ensure that losses will be
negligible even under high disease pressure. One
approach currently taken by us is to incorporate
durable resistance through limited backcrossing in
important currently grown cultivars. A few
exemplary cultivars are Inquilab 92 in Pakistan and
PBW343 in India. Because these cultivars are
moderately susceptible in Mexico, durable
resistance genes can be incorporated. We hope that
the derived lines will be similar to the original
cultivar for most agronomic features but possess
durable rust resistance and higher yield potential.
Results of similar efforts using an Attila line
released in Ethiopia indicate that it is possible to
simultaneously improve resistance and yield
potential. Durably resistant derivatives should
have better acceptance by farmers.

Johnson, R. 1978. Practical breeding for durable resistance to rust diseases in self
pollinating cereals. Euphytica 27:529-540.
Johnson, R. 1988. Durable resistance to yellow (stripe) rust in wheat and its
implications in plant breeding. In: N.W. Simmonds and S. Rajaram (eds.)
Breeding Strategies for Resistance to the Rusts of Wheat. Mexico, D.F.: CIMMYT.
pp. 63-75.
Mclntosh, R.A. 1992. Close genetic linkage of genes conferring adult-plant resistance
to leaf rust and stripe rust in wheat. Plant Pathol. 41:523-527.
Mclntosh, R.A., G.E. Hart, K.M. Devos, M.D. Gale, and W.J. Rogers. 1998. Catalogue
of gene symbols for wheat. A.E. Slinkard (ed.). Proc. 9th Int. Wheat Genetics
Symp., 2-7 Aug. 1998, Saskatoon, Canada. Vol 5:1-235.
Peterson, R.F., A.B. Campbell, and A.E. Hannah. 1948. A diagrammatic scale for
estimating rust intensity of leaves and stem of cereals. Can. J. Res. Sect. C.

Roelfs, A.P, R.P. Singh, and E.E. Saari. 1992. Rust diseases of wheat: Concepts and
methods of disease management. Mexico, D.F.: CIMMYT. 81 pp.
Rajaram, S., R.P Singh, and E. Torres. 1988. Current CIMMYT approaches in
breeding wheat for rust resistance. In: N.W. Simmonds and S. Rajaram (eds.).
Breeding Strategies for Resistance to the Rusts of Wheat. Mexico, D.F.: CIMMYT.
pp. 101-118.
Singh, R.P 1992. Genetic association of leaf rust resistance gene Lr34 with adult
plant resistance to stripe rust in bread wheat. Phytopathology 82:835-838.
Singh, R.P, and S. Rajaram. 1994. Genetics of adult plant resistance to stripe rust in
ten spring bread wheats. Euphytica:72:1-7.
Singh, R.P, J. Huerta-Espino, and S. Rajaram. 2000a. Achieving near-immunity to
leaf and stripe rusts in wheat by combining slow rusting resistance genes. Acta
Phytopathlogica Hungarica 35:133-139.
Singh, R.P, J.C. Nelson, and M.E. Sorrells. 2000b. Mapping Yr28 and other genes
for resistance to stripe rust in wheat. Crop Sci. 40:1148-1155.

Applying Physiological Strategies to Wheat Breeding

M.P. Reynolds, B. Skovmand, R.M. Trethowan,
R.P. Singh, and M. van Ginkel

Physiological Basis of Improved Yield and
Biomass Associated with the Lr19
Translocation from Agropyron elongatum
Although wheat yields have continued to improve
over the last 30 years (Calderini et al., 1999), the
physiological and genetic bases for this
improvement are only partially understood
(Reynolds et al., 1999). Nonetheless, yield increases
in several backgrounds have been shown to be
associated with introgression of a chromosome
segment containing Lrl9, namely Agropyron
7DL.7Ag (Rajaram, Singh, and Montoya,
unpublished data). The introgression of Lrl9 has
also been reported to be associated with increased
biomass (Singh et al., 1998).

As yield improvements due to increased
partitioning of biomass to grain yield reaches its
theoretical limit (Austin et al., 1980), breeding for
larger total biomass becomes increasingly
necessary if further genetic gains in yield potential
are to be realized. Higher biomass may be achieved
by: 1) increased interception of radiation by the
crop; 2) greater intrinsic radiation use efficiency
(RUE) throughout the crop cycle, and 3) improved
source-sink balance permitting higher sink demand
and, therefore, higher RUE during grainfilling.
Increased light interception could be achieved via
early ground cover or improved "stay-green" at the
end of the cycle. Improved RUE may be achieved,
for example, by decreasing photorespiration or
photoinhibtion (Loomis and Amthor, 1999), or
through improved canopy photosynthesis related
to factors such as canopy architecture. Better
source-sink balance may result from increased
partitioning of assimilates during spike
development so that grain number is increased;

this improves RUE during grainfilling as a
consequence of increased demand for assimilates.

Experiments were conducted to determine which of
these mechanisms were associated with greater
biomass in near-isogenic lines for the Lrl9 gene
complex (Table 1) bred as described by Singh et al.
(1998) and grown under optimal conditions in
Ciudad Obregon, northwestern Mexico, for two
cycles between 1998-2000.

Biomass, yield and yield components. Gene Lr19
was associated with increased yield, above-ground
biomass, and grain number in most backgrounds.
Averaged over both cycles, the main effect of Lrl9
was a 10%, 8% and 13% increase in yield, biomass,
and grain number, respectively, with the latter
coming mostly via increased numbers of grains per

Table 1. Biomass, yield and yield components for Lrl9
isolines in spring wheat backgrounds, averaged over two
cycles, Ciudad Obregon, Sonora, Mexico, 1998-2000.
Biomass Yield No. grains Grains/ Kernel
(g/m2) (g/m2) (per m2) spike wt (mg)
Main effect
Lr19 1,560 670 17,700 44.4 38.3
Control 1,440 610 15,600 39.9 39.4
P level 0.001 0.001 0.001 0.001 0.05
Background Lr19
Angostura + 1,575 630 15,500 37.9 40.9
Angostura 1,435 585 13,000 36.0 44.9
Bacanora + 1,495 645 18,700 50.5 34.4
Bacanora 1,525 620 17,500 43.0 35.6
Borlaug + 1,720 755 19,900 48.5 38.2
Borlaug 1,520 630 17,300 37.9 36.5
Star + 1,630 690 18,500 43.9 37.2
Star 1,590 640 17,400 39.7 37.0
Seri + 1,600 675 18,400 47.4 36.6
Seri 1,420 630 16,000 45.3 39.6
Oasis + 1,350 655 15,300 38.4 42.6
Yecora 1,180 545 12,700 37.5 42.9
P level (interaction) 0.05 0.05 ns ns 0.1

spike. Interaction between Lr19 and background
was significant for biomass and yield. In the case of
Bacanora, Lr19 had no effect on biomass and only
increased yield by 4%. At the other extreme Lr19
increased biomass and yield by 14% and 20%,
respectively, in Borlaug and Oasis (Table 1).

Radiation interception. The hypothesis that
increased yield and biomass associated with Lr19
may be attributed to improved light interception
was tested indirectly by measuring biomass shortly
after canopy closure. It was assumed that if
significant differences in light interception had
occurred they would be reflected in differences in
aboveground biomass, but no main effect was
found (Table 2). Visual observations of early light
interception support this conclusion. Differences in
light interception at the end of the season could
also account for differences in assimilation rate, but
visual assessment of green-leaf area duration
between the onset of leaf senescence and
physiological maturity revealed no apparent trend.

Radiation use efficiency. Differences in RUE are
difficult to assess directly on canopies; however,
biomass accumulation over a period of crop growth
(when not confounded by differences in light
interception or leaf senescence) is probably the best
way to estimate RUE. Therefore, in the current
study the biomass accumulated shortly after
canopy closure(50 d after emergence) and that
measured 7 d after flowering (Zadoks-70) was
calculated to see whether apparent differences in
RUE were associated with improved performance.
There was no significant effect of Lr19 on biomass
at either of these early growth stages (Table 2),
suggesting that the observed difference in final
biomass associated with Lr19 cannot be attributed
to intrinsic differences in RUE. Flag leaf
photosynthetic rates measured during booting on
all lines indicated no significant main effect of Lr19
(Table 2) on assimilation rates.

However, biomass accumulation during
grainfilling {i.e. between anthesis (Table 2) and
harvest (Table 1)} indicated that the main effect of
Lr19 was to increase RUE substantially (by 20%)

during this stage. The conclusion is supported by
the fact that photosynthetic rate measured on flag
leaves during grain filling was 16 % higher for Lr19
lines (Table 2). Since flag-leaf photosynthetic rate
and estimated RUE were not higher before
flowering, and that a principal effect of Lr19 was to
increase grain number (Table 1), it is likely that
higher photosynthetic rate and RUE measured
during grain filling were driven by higher sink
strength in Lr19 lines.

Source-sink balance: Duration of spike growth
phase and partitioning to spike. Many wheat
scientists believe that yield increases will result
from an improved balance between source and sink
(Evans, 1993). Although source and sink may co-
limit yield, evidence suggests that sinks are more
limiting even in modern lines (Slafer and Savin,
1994). Sink strength (i.e., grain number) is
determined during juvenile-spike growth; hence
this period of development is critical for
determining yield potential (Fischer, 1985). Such
observations have led to the idea that increasing
the relative duration of spike development may,
through increasing partitioning of assimilates to
the developing spike, increase grain number (Slafer
et al., 1996).

Table 2. Main effects of traits related to phenology,
partitioning (source-sink), and photosynthesis in near-
isogenic lines for the Lr19 translocation, Ciudad Obregon,
Sonora, Mexico, 1998-2000.
Trait +1r19 Check P level
Days to terminal-spikelet 42.5 40.5 0.001*
Days to anthesis 86 84 0.001
Days to maturity 124 123 0.001
Relative juvenile-spike growth 35% 35% ns
Partitioning (source-sink)
Spike weight 7 d after anthesis (g) 0.775 0.732 0.14
Anthesis harvest index 0.260 0.243 0.05*
Radiation use efficiency
Biomass 50d after emergence (g/m2) 370 390 ns
Biomass 7d after anthesis (g/m2) 960 940 ns
Photosynthesis-booting (umol m-2 s-1) 23.9 22.8 ns
Photosynthesis-grainfill (umol m-2 s-1) 20.9 18.0 0.001
* Interaction between Lr19 and genotype significant at P = 0.05.
t Anthesis harvest index = dry weight of spike 7 d after anthesis/total culm dry weight.

In the current study Lrl9 isolines were examined
for duration of juvenile-spike growth (i.e., between
terminal spikelet and anthesis), as well as for
relative partitioning of dry matter to spikes. While
no differences were found in the duration of spike
development, there was a highly significant
difference in partitioning of dry matter to spikes,
with the main effect of Lrl9 leading to a higher
relative investment of total biomass into the spike
(Table 2).

Increased yield and biomass of Lrl9 lines resulted
from and improved source-sink balance at
flowering, which led to higher demand-driven
photosynthetic rates during grainfilling. Light
interception by the canopy, rates of photosynthesis
prior to anthesis, and phenological patterns were
not affected by Lrl9 or associated with improved
yield and biomass.

Exploiting Genetic Resources to Optimize
"Source-Sink" Balance and Improve Stress
To boost yield in irrigated situations, it is widely
believed that genetic improvement must come
from simultaneously increasing both
photosynthetic assimilation capacity (i.e., source)
as well as improving the partitioning of assimilates
to reproductive sinks (Richards, 1996; Slafer et al.,
1996). At CIMMYT, a number of traits have been
identified with the potential to improve both
"source" and "sinks." Using this information, two
types of breeding work are underway: 1) traits are
introgressed into good backgrounds to establish
potential genetic gains to yield, and 2) "source"
and "sink" type traits are crossed together in an
attempt to obtain useful synergy with certain
recombinations and backgrounds. Other traits are
being identified which may be important under

Traits to improve spike fertility ("sink")
Spike anatomy. Most studies indicate that even in
improved germplasm, sink strength is still more
limiting to yield than photosynthetic capacity

(Slafer and Savin, 1994). Furthermore, studies with
Lrl9 isolines (Reynolds et al., 2000) have shown
that increased fertility has a direct effect on
radiation use efficiency during grainfilling,
resulting in higher biomass as well increased grain
number and yield. Thus a high priority is to find
genetic sources with increased fertility. Traits such
as large spikes, branched spikelets (Dencic, 1994)
and multi-ovary (Skovmand et al., 2000) are
potential sources. Another way to increase grain
number would be to increase the intrinsic fertility
of the spike by introgressing the multi-ovary floret
trait. This objective is being pursued currently in
CIMMYT's Wheat Program. Data for the Fl shows
that the trait is expressed better in some
backgrounds than others. However, average kernel
weight of FIs was in all cases higher than the multi-
ovary donor and in many cases higher than both
parents, and total grain weight per spike was
generally higher than for the parents.

Grain weight potential. Increased yield has been
associated considerably more with increased grain
number than grain mass (Calderini et al.,1999). In
theory, there is no reason why higher grain weight
potential, in addition to fecundity of grains, could
not increase sink demand and thereby drive both
higher yield and biomass. Synthetic wheats have
generally larger kernel weights than conventional
hexaploid cultivars, and recent work has shown
potential for even larger grain mass in synthetic
lines when assimilate availability was increased
during spike growth (Calderini and Reynolds,
2000). Introgression of high grain weight potential
may be expressed if complemented by traits that
increase assimilate availability during spike

Phenology. It has been hypothesized that spike
fertility may be increased by increasing the
allocation of assimilates to spike growth through
extending the relative duration of the juvenile spike
growth phase of development (Slafer et al., 1996).
Genetic variability in duration of juvenile spike
growth period is known to exist (Slafer and
Rawson, 1994), and germplasm collections have yet
to be examined comprehensively to find further

variation in the trait. Both grain weight potential
and grain number are largely determined during
juvenile spike growth phase; hence increasing
assimilate availability during this growth stage by
extending its duration may create a stronger sink
demand resulting from increased potential of both
yield components.

Traits to improve assimilate availability
Genetic progress in improving spike fertility will
almost certainly lead to a greater demand for
assimilates during grainfilling, and the
development of strong sinks may also be partially
dependent on a good supply of assimilates during
juvenile spike growth. Therefore, photosynthetic
capacity will need to be increased in tandem with
greater sink capacity. Traits that could be exploited
to increase light interception and RUE are
discussed below.

Green area duration. There are a number of
physiological and morphological traits related to
increasing light interception which have yet to be
fully exploited in modern wheats and for which
genetic diversity appears to exist in germplasm
collections. One is the ability to reach full ground
cover soon after emergence to maximize
interception of radiation. Richards (1996) has
developed lines with leaves that have a relatively
higher area (as a function of increased embryo
size), to achieve this result. Another is the ability to
maintain green leaf area duration ("stay-green")
throughout grainfilling (Jenner and Rathjen, 1975).
In theory, extra assimilates gained by increasing
early ground cover could contribute to increased
stem reserves and be tapped at later reproductive
stages to enhance potential kernel number and size.
A longer stay-green period would improve the
likelihood of realizing that potential. High intrinsic
chlorophyll concentration has also been associated
with improved stay-green in sorghum (Borrel, pers.

Genetic diversity for flag leaf chlorophyll has been
shown to exist in wheat landrace collections, with
some accessions exceeding modern lines such as

Seri-82 (Hede et al., 1999). Higher chlorophyll
concentration itself could theoretically increase
RUE in high radiation environments and has been
shown to be associated with yield in modern
durum wheats (Pfeiffer, pers. comm.).

Erect leaf. The erect leaf trait has the potential to
improve canopy RUE in high radiation
environments, since leaves that are exposed
perpendicularly to the sun's rays experience supra-
saturating light intensity (Duncan, 1971).
Germplasm collections were screened for erect
leaves at CIMMYT in the early 1970s, and the trait
introgressed into the wheat germplasm base from
sources such as Triticum aestivum ssp. sphaerococcum.
More erect leaf canopy types are characteristic of
many of CIMMYT's best yielding wheat lines
(Fischer, 1996). Genetic manipulation of leaf angle is
not complex, being controlled by only two to three
genes (Carvalho and Qualset, 1978). However, an
important question is whether manipulation of leaf
angle will permit further gains in RUE. Indirect
evidence suggests that the possibility may exist. For
example, when comparing two of the highest
yielding CIMMYT cultivars Bacanora 88 and
Baviacora 92, the former has a partially erectophile
leaf canopy, while the latter, which has higher
biomass, has lax leaves. We are currently trying to
introgress the erect leaf trait into Baviacora.

Traits to improve stress tolerance
A number of traits have been postulated in the
literature which may confer stress tolerance in
wheat (Figure 1). Not all traits would be useful in
all environments. Bearing in mind the specific
characteristics of an environment, a conceptual
model can be developed for a given target
environment encompassing a relevant sub-set of
traits. For example, it might be hypothesized that a
genotype adapted to a Mediterranean environment
with deep soil profiles should have high expression
of the following traits: early vigor, stem fructans
and biomass at flowering, and high CTD or other
water relations parameters during grainfilling,
indicating deep roots. The next step would be to
identify good sources of these traits and introgress

them separately and/or in combination into well
adapted backgrounds. CIMMYT's germplasm
collection is being screened for sources of these
characters; traits will be introgressed into stress
tolerant materials and tested in appropriate
environments. Populations are currently being
developed with diversity for stay-green, peduncle
length, and CTD to evaluate potential genetic gains
associated with these traits in stressed
environments in Mexico.

Using Physiological Tools to Improve
Breeding Efficiency
Over the last few years evidence has been
accumulating that physiological traits such as
stomatal conductance, canopy temperature
depression (CTD), and spectral reflectance may
have potential to be used as indirect selection
criteria for yield. For example, under warm,
irrigated conditions, CTD measured on yield trials
in Mexico was significantly associated with yield
variation in situ, as well as with the same lines
grown at a number of international testing sites
(Reynolds et al., 1994, 1997, 1998). Furthermore,
studies with recombinant inbred lines suggest that
significant genetic gains can be made in early
generations using CTD as an indirect selection

High spike photosynthesis

Cellular traits: osmotic adjustment, heat
'tolerance, ABA, etc.

raits: wax, rolling, thickness, etc.

e-anthesis biomass
S Early ground cover

Water relations traits: stomatal

Figure 1. Conceptual model of a drought tolerant wheat plant.

CTD and leaf conductance
Physiological bases of CTD. Leaf temperature is
depressed below air temperature when water
evaporates from its surface. The trait is affected
directly by stomatal conductance, and therefore
indirectly by many physiological processes
including vascular transport of water, carbon
fixation and other metabolic activity. As such, CTD
is a good indicator of a genotype's fitness in a given
environment. CTD measured during grainfilling
seems to be influenced by the ability of a genotype
to partition assimilates to yield, since CTD
frequently shows a better association with yield
and grain number than with total biomass
(Reynolds et al., 1997, 1998).

Canopy temperature depression can be measured
almost instantaneously using an infrared (IR)
thermometer in a small breeding plot. Since the
measurement integrates the temperature of several
plants at once, the error normally associated with
traits measured on individual plants is reduced.
Investigations into methodology in warm
environments (Amani et al., 1996) have shown that
CTD was best associated with performance when
measured at higher vapor pressure deficit (i.e.,
warm, sunny conditions and during grainfilling).
Irrigation status was not a confounding factor
within the normal frequencies of water application.
Similar investigations are being conducted for the
temperate environments, and under drought stress.
Preliminary data suggest that for irrigated
conditions (Figure 2) the protocols recommended
for warm environments are appropriate. Under
drought, studies were conducted recently to
established at what stage of development and at
what time of day differences in CTD are most likely
to be observed. Measurements were made in the
morning and afternoon between full ground cover
and late booting, and during grainfilling.
Performance seems to be better predicted by CTD
measured in the morning during grainfilling or
prior to heading (Table 3).

Rapid screening in breeding populations. CTD
measured on F5:8 recombinant inbred lines from the
cross Seri-82 /SieteCerros-66 explained over 40% of

the variation in yield (Figure 2). Other work has
demonstrated the effectiveness of using the trait in
selection nurseries to predict performance of
advanced lines in heat stressed target environments
(Reynolds et al., 1997, 1998). When CTD was
compared with other potential selection traits (grain
number, biomass, phenological data, and yield)
measured in the selection environment, none of the
other traits showed a greater association with
performance in the target environment than CTD.
The trait was also studied in three populations of
homozygous sister lines under drought stress. CTD
showed a highly significant association with yield
under drought when measured pre-anthesis in all
populations. CTD measured during grainfilling
tended to show a better association when measured
in the morning (Table 3).

In addition to yield, breeding objectives must take
into account multiple factors, such as disease
tolerance and phenology. Therefore, it would be
logical when incorporating CTD into a selection
protocol, to select for relatively genetically simple
traits such as agronomic type and disease resistance
in the earliest generations (e.g., F2-F3). Selection for
CTD could be employed in subsequent generations,
when more loci are homozygous, and perhaps in

y= 0.0004x + 3.0711 *
5.5- r2= 0.44 0

** ."**



3.5 .
2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500
Yield (kg ha-1)
Figure 2. Relationship between canopy temperature
depression (CTD) measured during grainfilling and yield of
random derived F5s: sister lines from the spring wheat cross
Seri-82 x SieteCerros-66, Ciudad Obregon, Sonora, Mexico,
Source: Reynolds et al., 1999.

preliminary yield trials. (Table 4). The possibility of
combining selection for both CTD (on bulks) and
stomatal conductance (on individual plants) is
another interesting possibility. In recent work at
CIMMYT (Guti6rrez-Rodrfguez et al., 2000),
stomatal conductance was measured on individual
plants in F2:5 bulks and showed significant
phenotypic and genetic correlation with yield of F5:7

Aerial infrared imagery. CTD can be estimated
remotely using aerial IR imagery. Work conducted
in Ciudad Obregon, Sonora, Mexico, showed that
aerial IR images had sufficient resolution to detect
CTD differences on relatively small yield plots (1.6
m wide). Data were collected using an IR radiation

Table 3. Correlation between CTD measured pre-heading and
during grainfilling on 25 recombinant inbred lines of Seri 82/
Baviacora 92, at different times of day, at two environments
in Mexico, 1999-2000.
Correlation with yield
Trait C. Obregon (810) Tlaltizapan
CTD mean 0.85** 0.84**
CTD AM prehead 0.82** 0.79**
CTD AM grainfill 0.79** 0.68**
CTD PM prehead 0.85** 0.72**
CTD PM grainfill 0.37 0.06
Days to maturity 0.29 -0.22
** Statistical significance at P>0.01.

Table 4. Theoretical scheme for incorporating physiological
selection criteria into a conventional breeding program
showing different alternatives for when physiological traits
could be measured, depending on resources available.
Breeding generation when selection to be conducted
Trait All generations F3 F4-F6_ PYTs/Advanced lines
Simple traits
Disease visual
Height visual
Maturity visual
Canopy type visual
Complex traits
Yield visual yield plots
CTD small plots yield plots
Porometry plants small plots yield plots
Chlorophyll plants small plots
Spectral reflectance small plots yield plots
Chlorophyll is sufficiently stable with respect to interaction with environment for
additional measurements not to be necessary.

sensor mounted on a light aircraft that was flown
at a height of 800 m above the plots. Data of plot
temperatures showed significant correlation with
final grain yield for random derived recombinant
inbred lines as well as advanced breeding lines
(Table 5). Considering that conditions were sub-
optimal at the time of IR imagery measurement
(intermittent cloud cover introduced significant
error into the measurements), the correlation with
yield compared quite favorably with that using
hand-held IR thermometers (Table 5).

For both methodologies, correlation with yield
were higher with random derived lines than with
advanced or elite lines that had already been
screened for performance. (This is to be expected
since nurseries would be skewed in favor of
physiologically superior lines after screening for
yield). The results validated the potential of aerial
IR imagery as a means of screening hundreds, or
potentially thousands, of breeding plots in a few
hours for CTD and, hence, for their genetic yield

Spectral reflectance
Sunlight reflected from the surface of breeding
plots (spectral reflectance) can be measured with a
radiometer and constitutes another potentially
useful technique for screening. Spectral reflectance
can be used to estimate a range of physiological
characteristics including plant water status, leaf
area index, chlorophyll content, and absorbed PAR

Table 5. Comparison of canopy temperature depression (CTD)
data from aerial infrared (IR) imagery with hand-held IR
thermometers, Ciudad Obregon, Sonora, Mexico, 1996-
Correlation of CTD with yield
Aerial Hand-held
Trial Phenotypic Genetic Phenotypic Genetic
RILs (Seri-82 x 7Cerros-66)
random derived sisters 81 0.40** 0.63** 0.50** 0.78**
Advanced lines
(Bread wheat) 58 0.34** t 0.44**
* Denotes statistical significance at 0.01 level of probability.
t Genetic correlations not calculated due to design restrictions.
Source: Adapted from Reynolds et al., 1999.

(Araus, 1996). The technique is based on the
principle that certain crop characteristics are
associated with the absorption of very specific
wavelengths of electromagnetic radiation (e.g.,
water absorbs energy at 970 nm). Different
coefficients can be calculated from specific bands of
the crop's absorption spectrum, giving a semi-
quantitative estimate (or index) of a number of
crop characteristics.

In preliminary experiments, the indices NDVI
(normalized difference vegetation index), WI
(water index), SR (simple ratio) and SIPI (structural
independent pigment index) all showed significant
correlation with yield, biomass, and leaf area index.
The measurements were made during grainfilling
on 25 advanced lines selected for diverse
morphology, with yields ranging from 5 to 9 t/ha
in Obregon. Performance was best correlated with
NDVI and was a little higher for biomass (Figure 3)
than for yield. Other indices are also being
explored; "green NDVI," which we believe will
permit better resolution at higher biomass levels, is
observed with red NDVI (Figure 3). We are
currently evaluating the use of NDVI (red and
green) as a rapid screening tool for yield, nitrogen
use efficiency, and triticale forage yield.






0.40 1
10,000 12,000

14,000 16,000 18,000 20,000 22,000 24,000
Biomass (kg/ha)

Figure 3. Relationship between spectral reflectance index NDVI
(normalized difference vegetation index) measured during
grainfilling and biomass of irrigated spring wheat advanced
lines, Ciudad Obregon, Sonora, Mexico, 1996 1997.
Source: Reynolds et al., 1999.

* *
;. ...

Sy= -3E -09x2 + 0.0001x 0.4153
r2= 0.5588

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CIMMYT Wheat Research and Capacity Building

in Eastern, Central, and Southern Africa

D.G. Tanner and T.S. Payne

CIMMYT's activities in Eastern, Central, and
Southern Africa are focused on developing broad
institutional support for the informal maize and
wheat research networks that have evolved over
the years. To attain this objective, CIMMYT
provides support and guidance to the Eastern and
Central Africa Maize and Wheat (ECAMAW)
Research Network, operating under the auspices of
the Association for Strengthening Agricultural
Research in East and Central Africa (ASARECA),
and the Maize and Wheat Improvement Research
Network (MWIRNET), operating under the
auspices of the Southern African Coordination
Council for Agricultural Research (SACCAR). Over
the past decade, funding for wheat research
activities within these networks has been provided
by the Canadian International Development
Agency (CIDA), the European Union, and the
CIMMYT core unrestricted budget.

The Eastern Africa Cereals Program (EACP),
funded by CIDA for the past 15 years, has
contributed to the enhancement of maize and
wheat production throughout Eastern Africa. Over
that time, the EACP has enabled researchers from
the region to develop and disseminate new crop
management practices and varieties to improve
maize and wheat cropping. This contribution is
important, given that the vast majority of people in
the region depend on agriculture for food and cash
income. As catalysts for better research and
increased farm-level impact in the region, EACP
and ECAMAW are involved in the entire range of
activities that make a research network truly
effective, ranging from research planning,
implementation, and budgeting to the training of

Some Wheat Data for Eastern, Central, and
Southern Africa
Total 1994 wheat importation and production in
Eastern, Central, and Southern Africa (ECSA) were
4.7 and 2.3 million t, respectively, with a
corresponding total wheat area of 2.8 million ha.
Annual national wheat production totals ranged
from 6,000 t in Uganda, to 1,125,000 t in Ethiopia
and 2,321,000 t in South Africa; national wheat
areas ranged from 5,000 ha in Uganda, to 750,000 ha
in Ethiopia and 1,425,000 in South Africa.

Per capital wheat consumption in the region ranges
from a low level of 2.5 kg person-1 year in Uganda
to as high as 75.6 kg person' year in South Africa.
In general, during the past decade, per capital
consumption has decreased in all countries in ECSA
except Ethiopia and Sudan.

The mean regional wheat grain yield of 1.9 t ha-1
conceals wide disparities in production potential
and performance as influenced by diverse agro-
ecological conditions and production systems. On a
national basis, mean yields range from 0.8 t ha-1 in
Burundi to 6.3 t ha-1 in Zimbabwe, the highest
average wheat yield realized in the developing
world. During the 1985-95 period, the rate of
increase of wheat yield per hectare was 2.1% year-
in Sudan and 3% year' in Ethiopia.

Since 1980, 218 wheat and triticale cultivars have
been released in ECSA, consisting of 196 bread
wheat, 13 durum wheat, and 9 triticale cultivars.
Excluding South Africa, cultivars selected and
released from CIMMYT-bred introductions and
segregating populations accounted for 110 of the
147 cultivars released since 1980 in ECSA. This
implies that the national wheat research programs

in ECSA rely heavily on CIMMYT wheat
germplasm (i.e., 75% of released cultivars are
derived directly from CIMMYT germplasm).
Regarding germplasm requirements, South Africa
is unique in ECSA, with spring and winter types
grown, as well as F1 hybrids. Of the 71 wheat and
triticale cultivars released in South Africa since
1980, 40% involved CIMMYT-derived germplasm,
21% were of unknown origin (i.e., the parentage of
commercial F, hybrids), with the remaining
releases-primarily winter habit types-utilizing
non-CIMMYT germplasm.

Diseases Prevalent in ECSA
In recent years, yellow rust has supplanted stem
rust as the rust pathogen of primary concern in
ECSA. Over the past ten years, single step
mutations have resulted in the evolution of new
virulences in the yellow rust pathogen in Kenya,
demonstrating the danger of breeding for race-
specific resistance. From 1969 to 1989, at least 19
races were identified. In August 1996, yellow rust
was observed for the first time in South Africa, and
within a year, the disease had spread to most wheat
producing areas in the country. Infected grass
species serving as accessory hosts were also
observed in the Western Cape and Eastern Free
State, with "6E16" identified as the originating
race. MWIRNET/RSA is currently sponsoring a
germplasm shuttle breeding program whereby
South African wheat germplasm is screened for
resistance to yellow rust in a location in
southwestern Uganda considered to be a global
hot-spot for this pathogen.

CIMMYT is also supporting distribution of a Sub-
Saharan Wheat Disease Monitoring Nursery. This
nursery is intended to validate regional varietal
disease performance while monitoring potential
performance criteria important for farmers and
NARS cooperators throughout East, Central, and
Southern Africa.

Septoria nodorum, S. tritici and S. avenae f.sp.
triticeae, loose smut, scab, root rot, take-all and
Helminthosporium spp. cause significant yield losses
in ECSA. Cereal aphids (Schizaphis graminum,

Rhopalosiphum padi, R. maidis, Sitobion avenue and
Diuraphis noxia) can also be major pests of wheat in
this region, and several species serve as vectors in
the transmission of barley yellow dwarf virus.
Yield losses of up to 47% due to BYDV have been
reported in Kenya. Yield losses of >60% due to D.
noxia have been reported in South Africa, and, at
present, all bread wheat cultivars grown in the
summer rainfall zone of RSA require genetic
resistance to this pest. MWIRNET/RSA is currently
supporting research to identify an indicator
capable of differentiating Dn resistance genes by
assessing differences in aphid feeding behavior.

Industrial Quality
The free-market, global economy promotes the
production and consumption of the lowest cost
products. Throughout ECSA, however, limited and
unscientific information (i.e., market biased) is
available on the relative milling and baking quality
of nationally produced wheat. ECAMAW and
MWIRNET have promoted Regional Industrial
Quality Cooperative Testing Trials to enable
regional wheat breeders, producers, processors,
and grain marketing organizations to better
understand the inherent milling, baking, and
nutritional quality aspects of advanced germplasm
and cultivars.

Agronomic Research
A special feature of the ECAMAW collaboration is
agronomic research targeted at farm-level problems
that must be resolved to promote long-term
agricultural productivity in the region. Wheat crop
production recommendations that have recently
been provided to extension services due to
ECAMAW research activities include:

* The semidwarf bread wheat cultivars HAR604
("Galama") and HAR1685 ("Kubsa") recently
released in Ethiopia exhibit the highest
productivity and profitability across a range of
crop management systems, and result in the
highest marginal rates of return under increased
input levels. The profitability of bread wheat
production in the central highlands of Ethiopia can
be markedly increased by focusing the application

of improved crop management practices on these
specific cultivars.
* Pendimethalin plus bromoxynil plus MCPA offer
effective control of the major grass (Sorghum
arundinaceum and Echinochloa colona) and broadleaf
weeds (Zelya pentandra, Portulaca oleraceae and
Corchurus olitorius) in irrigated wheat in the Awash
Valley of Ethiopia. A combination of these three
chemicals effectively controlled both grass and
broadleaf weeds and significantly increased grain
* Economic optimum rates of N and P fertilizer for
the high-yielding semidwarf bread wheat
HAR1685 ("Kubsa") were determined under the
improved drainage technology known as broad
bed and furrow (BBF) in Ethiopia. Under two
contrasting cost/price scenarios, partial budget
analysis indicated that 138-46 kg N-P205 ha-1 was
the most profitable of the nutrient combinations
* In Ethiopia, faba bean was recommended for a
three-year crop rotation with wheat. The rotation
improves wheat grain yield by as much as 65% in
year 1 and 35% in year 2, enhances wheat response
to phosphorus fertilizer, fixes as much as 210 kg
ha-1 of nitrogen, and improves soil nitrogen
balances by almost 65 kg ha-1 of nitrogen. The
research service has established demonstration
plots for the technology, which is also being
promoted by the national extension program.
* Higher N application rates recommended for bread
wheat in Ethiopia provide a return on the
investment in fertilizer in excess of 311, r and an
additional 12 kg grain for each kg of N applied.
Interestingly, in Vertisol zones in Ethiopia, the N
application exhibited a residual benefit in year 2
equivalent to 41i r of the response seen in year 1.
The new N recommendations have been
disseminated by the national bread wheat
extension effort and through Sasakawa Global
2000. Urea use on wheat rose sevenfold between
1994 and 1998, and national wheat production rose
by over 41 r during the same period.
Technologies in the pipeline include:
* Economic analysis of long-term crop management
trials, essential to the interpretation of the
agronomic results, is being targeted for analysis
and summarization.
* Competition effects of three broadleaf weed species
(Guizotia scabra, Amaranthus retroflexus and Galium

spurium) on the grain yield of bread wheat have
been studied in Ethiopia; economic thresholds for
herbicidal intervention in relation to weed seedling
density have been determined.
* Twenty genotypes of bread wheat, previously
selected for high grain yield potential under weed-
free conditions, are being tested for yield potential
under competition with Avena sativum (as a proxy
for grass weeds).

Technology Dissemination

Within the ECSA region, the Kulumsa research
center of EARO, Ethiopia is widely recognized as a
center of excellence for bread wheat research. This
center actively collaborates in the regional
networks; thus, a study was initiated in
collaboration with CIMMYT's Natural Resources
Group to identify the specific areas within ECSA for
which the transfer of materials, technologies, or
information to and from Kulumsa would be
appropriate. Climate similarity maps contained
within the Africa Maize Research Atlas were used
to address this question at the regional level.

The results highlighted the climatic similarity of
Kulumsa to most of the major wheat producing
regions in Eastern Africa (Figure 1), and supported

i Climate similarity zone for Kulumsa
5 month optimum season
+/- 20% precipitation & evapo.
+/- 10% max & min temperature
Figure 1. Climate similarity map for the Kulumsa Research
Center, Ethiopia.

the pivotal role of Kulumsa in the regional
networks. One surprise finding was that a
significant area in eastern South Africa exhibited
climatic similarity to Kulumsa, yet this is not a
wheat producing region. This prompted an
investigation into what additional factors were
involved in this particular region. It was
discovered that several factors were involved,
including difficult terrain, wheat not being a crop
of choice for traditional smallholders, and high
levels of commercial production in southwestern
areas. This highlights the fact that factors,
including socio-economic issues, must also be
considered when examining crop distribution.

Empowering Women Farmers
Another important aspect of EACP and ECAMAW
is an emphasis on empowering the region's women
farmers as well as sensitizing the researchers (male
and female) who work on their behalf. The
importance of women to Africa's agricultural
economy is indisputable, but many researchers and
extension workers have not previously received
training in methods that would ensure that
research benefits female producers. To address this
problem, ECAMAW launched a series of gender
analysis and training initiatives in concert with the
Centre for Women's Studies and Gender Analysis,
Egerton University, Kenya. Over the last three
years, these initiatives have included:

* Participation of the ECAMAW steering committee
in a gender orientation training session.
* A course entitled "Training of trainers in gender
analysis and planning for the ECAMAW research
network" empowered researchers to conduct
gender analysis training for colleagues in their
respective national programs.

* Of the 228 people included in ECAMAW-
sponsored training activities during 1997-1999, 49
(21.7%) were women-more than the proportion of
female scientists (1 5.1 ) in national maize and
wheat research programs in the region.
* Reflecting an initiative to empower women
scientists, women researchers led 28 experiments
funded by the network's small grants program
during 1997-1999.
* More studies on gender issues in agriculture are
being undertaken. During 1998, the network
funded a synthesis of farm-level survey
information generated in four countries,
highlighting the roles of women in maize and
wheat cropping systems and identifying research
domains requiring gender-differentiated
approaches. Since 1997, six studies on the adoption
of technologies, including the collection of gender-
disaggregated data, have been funded by the
network's small grants program.
* All research proposals submitted to ECAMAW's
small grants program are required to include an
analysis of the gender dimensions and implications
of proposed technological interventions.
* More than 25 research proposals funded each year
by this program have included a gender analysis
* Under the small grants program, 31 projects have
examined issues that are significant to women
farmers (e.g., evaluation of technologies for soil
fertility management; the effects of green manure
and cropping sequences on soil fertility; the role of
drought tolerant legumes in cereal production
systems; participatory evaluation of bread wheat
technologies; on-farm evaluation of integrated crop
management practices for weed control; and
informal seed production, distribution, and
diffusion for resource poor farmers).

Chinese Wheat Production and the

CIMMYT-China Partnership

He ZhonghuI

Wheat Production and Challenges
Wheat is the second most important crop in China.
During the 1996-2000 period, on average, Chinese
wheat area was 29.1 million ha, yearly production
112 million tons, and yield 3,850 kg/ha. Compared
with the 1991-95 period, the wheat area decreased
by 2.0%, but production and average yield
increased 10.7% and 12.9%, respectively. However,
Chinese wheat industry faces great challenges with
its upcoming entrance into the World Trade
Organization (WTO). Thus Chinese wheat needs to
compete successfully on the international market
and with other crops on the domestic market.

Key to achieving sustainable wheat production in
China are 1) improving wheat yield potential and
industrial quality; 2) reducing the use of inputs
such as irrigation water and fertilizer, 3) protecting
the environment (for example, by reducing
pesticide use); and 4) increasing wheat production
efficiency and profitability. Also important is the
increased incidence of wheat diseases. For
example, due to the breakdown of yellow rust
resistance in Fan 6 and its derivatives, there have
been epidemics of yellow rust in southwestern
China almost every year since 1996. Also, sharp
eyespot and take-all have become major problems,
while control of powdery mildew and head scab
still needs to be strengthened.

Wheat quality has been a limiting factor because
most Chinese wheat varieties were selected based
on yield performance. The Chinese Government
has eliminated the protected price system in
Yangtze and other spring wheat regions where

1 CIMMYT-China. C/O Chinese Academy of Agricultural
Sciences (CAAS), No. 12 Zhongguancun South Street,
Beijing 100081, China

wheat quality is poor; consequently, the wheat area
in the 1999-00 season was reduced by 1.6 million ha
compared with the 1998-99 season. Wheat prices
hit a historic record low (US$ 95 to 120 per ton),
causing farmers to start growing other crops.
However, contract production has been
encouraged, and the milling industry is allowed to
buy wheat directly from farmers, who usually
receive premium prices for good quality wheat.

Wheat trade organizations in USA, Canada,
Australia, and EU are pressing China to increase
wheat importation. Multinational companies such
as Monsanto and Limargain have initiated their
wheat efforts in China. Therefore, CIMMYT must
work closely with Chinese wheat programs to
provide technical support for the sustainable
development of the wheat industry. Progress on
CIMMYT-China joint activities are presented in this

Wheat Quality Improvement
A wheat quality laboratory has been jointly
established by the Chinese Academy of
Agricultural Sciences (CAAS) and CIMMYT. Major
activities include germplasm introduction, testing,
and distribution, standardization of the quality
testing system, investigation of genotype and
environment interaction on major quality traits
across China, noodle and steamed bread quality,
soft wheat quality, milling quality, genetics and
molecular markers for quality traits, training, and
international cooperation. The research programs
are supported by the Chinese Ministry of
Agriculture, the National Natural Science
Foundation of China, GRDC, CIMMYT, and CAAS.

Regional wheat quality classification
A wheat quality map for China will be constructed
based on climate data (temperature, rainfall), soil
type, farming system, fertilizer use, and quality
data collected in China over the last 15 years. The
official document will be finalized and released in
2001. To date, three regions have been recognized:

* Winter and facultative wheat region (Zones I and
II); hard white and medium-hard types for making
bread, noodles, and steamed bread.
* Autumn-sown spring wheat region (Zones III, IV,
and V); soft red type, but also medium-hard red
type for steamed bread and noodles. Sprouting
tolerance needed.
* Spring-sown spring wheat region (Zone VI, VII,
and VIII); hard red and medium-hard types for
making bread, steamed bread, and noodles.
Sprouting tolerance needed.
Noodle quality
Noodles and steamed bread are the major wheat
products consumed in China. However, laboratory
testing procedures for the required quality have
not yet been established, which limits quality
improvement efforts. One hundred four varieties
and advanced lines were sown in two locations in
the 1997-98 and 1998-99 crop seasons, respectively,
to investigate the association between wheat
quality traits and the quality of dry white noodles
and to identify wheat varieties conferring good
noodle making quality. Major results are presented
in Table 1.

Grain hardness, water absorption rate, and
tolerance index have a significant negative
association with noodle quality, while protein

content, SDS sedimentation value, stability,
extension area, and peak starch viscosity have a
significant positive association with noodle quality
(Table 1). Therefore, medium hardness, high
whiteness, medium protein content, medium to
high gluten strength, good extensibility, and high
starch peak viscosity are desirable for good noodle
quality. Eight Chinese wheat varieties (Ph82-2-2,
Zheng 81-1, Lu 955159, Wenmai 6, Shaanyou 225, Lu
935031, Yangmai 5, and Zhongyou 9507) and five
Australian varieties (Eradu, Sunstate, Hartog,
Cadoux, and Gamenya) were identified to confer
good noodle quality. It is also possible to develop
varieties combining good bread and noodle quality;
Sunstate, Hartog, Lu955159, and Zhongyou 9507 are
good examples. A laboratory method for evaluating
noodle quality has also been established.

Steamed bread quality
Seventy-eight wheat varieties were sown in the
1997-98 and 1998-99 crop seasons to investigate the
association between wheat quality traits and the
quality of northern-style steamed bread, and to
identify varieties conferring good steamed bread
making quality. The major results are presented in
Table 2.

Protein content, gluten strength, and extensibility
are positively correlated with steamed bread
volume and elasticity, but negatively associated
with appearance when manual procedures were
used (Table 2). Therefore, quality requirements for
steamed bread will depend largely on the
processing procedure. Weak to medium gluten type
is desirable for making steamed bread by hand,
while medium to strong gluten type will produce

Table 1. Correlation coefficients between wheat quality traits and noodle quality parameters.
Traits Color Appearance Palate Elasticity Sticki-ness Smooth-ness Taste Total score
Hardness -0.39** -0.30** 0.11 0.00 -0.07 -0.31** -0.35** -0.13
Whiteness 0.54** 0.46** 0.00 0.16 0.27** 0.39** 0.55** 0.34**
Protein content -0.14 -0.12 0.22 0.28** 0.19* -0.16 -0.12 0.17
SDS sedi. -0.02 0.00 0.35** 0.56** 0.48** 0.00 0.27** 0.46
Water absorption -0.41** -0.34** -0.01 -0.19 -0.24* -0.42** -0.48** -0.31**
Stability -0.02 0.01 0.21 0.50** 0.45** 0.01 0.23* 0.39**
Tolerance index -0.06 -0.10 -0.36** -0.58** -0.48** -0.10 -0.28** -0.54**
Extension area -0.15 -0.10 0.30** 0.58** 0.46** -0.06 -0.11 0.40**
Peak viscosity 0.31** 0.28** 0.13 0.39** 0.34** 0.24* 0.50** 0.41**
N = 104; correlation coefficients were calculated based on two locations/two years average.
* and ** indicate significance at 5% and 1% probability level, respectively.

good steamed bread using
mechanized processing. Good
flour whiteness and high peak
viscosity contribute positively to
the desirable color of steamed
bread. However, 16 varieties (6
with strong gluten, 5 with
medium gluten, and 4 with weak
gluten) were identified to confer
good steamed bread making
quality using both procedures. It
is possible to develop varieties
combining good bread and
steamed bread quality; Jinnan 17
is a good example. This also
indicates that further work is
needed to better understand
steamed bread making quality.

Table 2. Correlation coefficients between wheat quality traits and the quality of
northern-style steamed bread.
Traits Volume Appearance Color Structure Elasticity Stickiness Total score
Hardness a0.45** -0.19 -0.22 0.33** 0.36** 0.13 0.27*
b0.16 0.02 -0.21 0.22 0.07 0.16 0.09
Whiteness -0.39** 0.10 0.41** -0.32* -0.33** -0.26* -0.29*
0.00 -0.03 0.39** -0.24* 0.05 -0.05 0.01
Protein content 0.45** -0.29* -0.19 0.15 0.33** -0.06 0.15
0.28* -0.18 -0.08 0.09 0.13 0.11 0.05
SDS Sed. 0.39** -0.22 0.12 0.15 0.42** -0.03 0.26*
0.53** 0.05 0.12 0.21 0.39** 0.28* 0.39**
Water absor. 0.33** -0.08 -0.17 0.19 0.29* 0.13 0.18
0.05 -0.10 -0.23 -0.02 -0.19 -0.07 -0.15
Stability 0.20 -0.44** 0.07 -0.06 0.24* -0.28* -0.09
0.57** -0.03 0.26* 0.03 0.46** 0.29* 0.33**
Extension area 0.25* -0.50** 0.10 -0.07 0.21 -0.36** -0.10
0.51** -0.07 0.23 0.05 0.37** 0.32** 0.30*
Peak viscosity -0.16 0.03 0.51** 0.15 0.27* 0.37** 0.32*
0.17 0.09 0.30* -0.12 -0.09 0.03 0.09
a, b Correlation coefficients derived from manual and mechanized procedures, respectively, in the 1998-99 season.
* and ** indicate significance at 5% and 1% probability level, respectively.

Table 3. CIMMYT germplasm showing outstanding
Shuttle Breeding and Germplasm Exchange performance in China.

More than 35 Chinese institutes receive CIMMYT
wheat international nurseries annually. CIMMYT
wheat could be used directly in the spring wheat
region, particularly in Xinjiang and Yunnan.
Outstanding germplasm selected for the last several
years is presented in Table 3.

CIMMYT wheat has been extensively crossed with
Chinese wheats; leading varieties derived from
CIMMYT wheat are presented in Table 4.

Regional wheat screening nurseries have been
established, and five sets of screening nurseries
were distributed to wheat programs in China.
Details are presented in Table 5.

Wheat Agronomy: The Bed Planting System
The area planted using the bed planting system in
China was 600 ha in 2000. The system benefits both
the wheat and maize crops in a wheat-maize
rotation. Bed planting has several advantages over
the traditional system: ease of planting, labor-
saving, 15-20 cm plant height reduction and
improved lodging resistance, fewer diseases, easy
application of fertilizer and irrigation, and yield
increases of 10-15%. However, the lack of small
machines for family use limits the popularity of this

Name/Cross Location
Ningmai 10 (SHA 7/PRL"s"//Vee 6) Jiangsu, released variety
CM 95117
E001 (ATTILA) Yunnan, released variety
S001 (unknown) Yunnan, leading variety
R 101 (AGA/4*HORKS) Yunnan, leading variety
Milan Sichuan
NG8319//SHA4/LIRA Yunnan
Kehong 16 Heilongjiang

Table 4. Outstanding quality of wheat varieties derived from
CIMMYT germplasm.
Variety Major trait germplasm Location
Zhongyou 9507 bread/noodle quality Yecora F 70 W*/Zone I
Jinan 17 bread/steamed bread Saric F70 F/Zone II
Shandong935031 noodle quality Saric F70 F/Zone II
Chuanmai 30 rust resistance Genaro 81 S/Zone IV
Liaochun 10 bread quality Mexipak 66 S/Zone VI
Ningchun 4 bread quality Sonora 64 S/Zone VIII
Yunmai 39 drought tolerance Flicker"s" S/Yunnan
Xinchun 6 high yielding Siete Cerros S/Xinjiang
W= winter wheat F= facultative wheat, s= spring wheat.

Table 5. Regional screening nurseries distributed by CIMMYT-
CAAS in China.
Line Location/
Type number Institute
Winter and facultative wheat observation nursery 70-80 35
Quality wheat observation nursery 50 40
South China winter wheat observation nursery 20 10
Spring wheat observation nursery 35-40 12
CIMMYT wheat quality observation nursery 30 14

technology, although big machines are available in
Heilongjiang Province.

Training and Information Exchange
CIMMYT and CAAS have jointly organized wheat
breeding meetings and training courses as
presented below. These events have greatly
enhanced the scientific exchange between CIMMYT
and Chinese wheat breeding programs.

* CAAS-CIMMYT Wheat Breeding Meeting, Beijing,
* China-CIMMYT Wheat Breeding Meeting, Henan,
* China-CIMMYT Wheat Quality Training Course,
Beijing, 1998
* China-CIMMYT Spring Wheat Breeding Meeting,
Inner Mongolia, 1999
* China-CIMMYT Wheat Quality Training Course,
Beijing, 1999
* National Wheat Breeding Meeting, Shandong, 2000
* International Scab Symposium(co-sponsor),
* GxE training course for multi-location data
analysis, Beijing, 2000
In 1997-2000, seven MSc students did their thesis
work at the CAAS-CIMMYT quality lab. Currently,
there are 10 postgraduates working on wheat
quality, powdery mildew, yield potential, and
molecular markers.

The following CIMMYT publications have been
published in Chinese. CIMMYT also published
three wheat special reports on Chinese wheat.

CIMMYT publications in Chinese:

* Zou Yuchun (translator), 1994. Collection of
CIMMYT Wheat Breeding Papers. Sichuan Science
and Technology Press.

* He Zhonghu (translator), 1995. CIMMYT Wheat
Breeding Methodology. China Agrotech Press.
* Yang Yan (translator), 1999. Bunt and Smut
Diseases of Wheat: Concepts and Methods of
Disease Management. Wilcoxson R.D., and E.E.
Saari, eds. China Agrotech Press.
* He Zhonghu (translator), 1999. Increasing Yield
Potential in Wheat: Breaking the Barriers.
Reynolds, M.P., S. Rajaram, and A. McNab, eds.
China Science and Technology Press.
* Sun Jiazhu (translator), 2000. CIMMYT 1998-99
World Wheat Facts and Trends. Global Wheat
Research in a Changing World: Challenges and
Achievements. Beijing Academy of Agricultural
CIMMYT publications on Chinese wheat:

* He Zhonghu and Chen Tianyou. 1991. Wheat and
Wheat Breeding in China. CIMMYT Wheat Special
Report No 2.
* Yang Zouping. 1994. Breeding for Resistance to
Fusarium Head Blight of Wheat in the Mid- to
Lower Yangtze River Valley of China. CIMMYT
Wheat Special Report No 26.
* He Zhonghu and S. Rajaram. 1997. China/
CIMMYT Collaboration on Wheat Breeding and
Germplasm Exchange: Results of 10 Years of
Shuttle Breeding (1984-94). Proceedings of a
conference held in Beijing, China, July 3-5, 1995.
CIMMYT Wheat Special Report No. 46.
* He Zhonghu, S. Rajaram, Xin Zhiyong, and Huang
Jizhang. 2000. Chinese Wheat Breeding and
varieties pedigrees (in press).

The author is grateful to Dr. R.J. Pefia for his
technical support, and to Zhang Yan, Wang
Deshen, Zhou Guiying, Yan Jun, Liu Jianjun, Zhang
Yong, and Liu Aihua for their assistance in the
CIMMYT-CAAS wheat quality program.

Liu Aihua. 2000. Investigation on the association between wheat quality traits and
the performance of northern-style Chinese steamed bread. MSc Thesis, CAAS.
Liu Jianjun. 2000. Investigation on the association between wheat quality traits and
the performance of Chinese dry noodle quality. MSc Thesis, CAAS.
Z. He, M. van Ginkel, and S. Rajaram. 2000. Progress of the China/CIMMYT
cooperation on shuttle breeding and germplasm exchange aimed at combining
high yielding potential with resistance to scab. Proceedings of the international
symposium on wheat improvement for scab resistance. pp. 157-160.

Improving Wheat Production in

Central Asia and the Caucasus

A. Morgounov, M. Karabayev, D. Bedoshvili, and H.-J. Braun

The countries of Central Asia (Kazakhstan,
Kyrgyzstan, Tajikistan, Turkmenistan, and
Uzbekistan) and the Caucasus (Armenia,
Azerbaijan, and Georgia), with a population of 62
million people, produce 15-16 million tons of
wheat a year. The wheat-growing environment is
divided into two distinct regions (Figure 1). The
Southern region (36-440N latitude), occupying 5-6
million ha across all eight countries, grows fall-
planted winter or facultative wheat mostly under
irrigation (60-70%) The main crops are cotton,
sugar beet, maize, and vegetables. Rainfed wheat is
planted on the other 30-40% of the area, mostly on
hillsides or mountains where irrigation is not
possible. The major biotic constraint for wheat
production is yellow rust, which has affected the
region in the last 3-5 years. Yield potential in the
best irrigated fields (Fergana Valley, Chui Valley,
and Samarkand) is close to 5-6 t/ha. However,
average yield barely reaches 2 t/ha due to poor
agronomy and lack of inputs.

The Northern region (48-520N latitude), 10-11
million ha located only in Kazakhstan, grows
spring planted spring wheat with daylength
sensitivity. There is a comparable wheat area in

Figure 1. Map of major wheat-producing regions in Central
Asia and the Caucasus.

Russian Siberia across the border. Though this area
is not part of CIMMYT's mandate, the similarity of
environment and strong traditional links between
researchers suggest that activities in the North
should involve both Kazakhstan and Siberia. Wheat
is the principal crop in this region, where it is
rotated with fallow every 3-4 years. It is planted in
May and harvested in August. Drought represents a
major abiotic stress. Septoria, leaf rust, and root rots
are the major diseases in the region.

History of CIMMYT Cooperation in CAC
CIMMYT cooperation with Central Asia and the
Caucasus (CAC) goes back to the time when this
region was part of the Soviet Union. In the 1970s
there was a substantial flow of Mexican germplasm
to the USSR and wide-scale testing of new wheat
varieties in all agroecological environments. Bread
and durum wheats (Siete Cerros and Oviachik 66)
that proved competitive were released in areas with
mild winters (southern Russia, Azerbaijan,
Uzbekistan, and Tadjikistan). At the same time,
many lines were used in crosses, and a number of
modern wheat cultivars in the region have Mexican
germplasm in their pedigrees.

The initial dynamic germplasm exchange of the
1970s was followed by a pause in the 1980s, when
the germplasm was channeled through the Vavilov
Institute in St. Petersburg; usually it was delayed or
never reached the breeding programs. In the 1990s
interest in collaborating with the region was
renewed as the newly independent states were able
to establish direct linkages with CIMMYT. After
independence, research programs found themselves
isolated and in need of new and better sources of
germplasm, methodologies, and information.

In 1992-93 the CIMMYT office in Turkey working
on winter wheat in cooperation with Turkey and
ICARDA initiated germplasm exchange and
supplied several nurseries to the key breeding
programs in CAC, as well as Russia and the
Ukraine. In 1994-95 the first exchange visits by
scientists facilitated establishing better cooperation
and defining priorities. Since 1996-97 germplasm
exchange and visits by scientists have become

In 1998 USAID for the first time donated funds
targeted to the region. The same year Nobel
Laureate Dr. Norman E. Borlaug and Dr. S. Rajaram,
CIMMYT Wheat Program Director, visited
Kazakhstan and reached an agreement about
establishing a CIMMYT regional office there. In
1999 the CGIAR allocated restricted funds for
cooperation with CAC, and a CIMMYT office was
opened in Almaty, Kazakhstan. Later in 2000 the
President of Kazakhstan signed a law "On the
cooperation between the Republic of Kazakhstan
and CIMMYT in agricultural science," thus giving
high official recognition and status to CIMMYT in
Kazakhstan. Since 1998 the program has undergone
dynamic evolution and expansion.

Program Structure and Objectives
Since 1995-96, when the program for CAC was
being formulated, CIMMYT recognized the
following features of the region: relatively high
potential of local scientists, isolation from the global
scientific community in terms of scientific
information and language, lack of a targeted
research approach that takes into account farmers'
interests, deteriorated infrastructure and machinery
in research programs, little regard for sustainability
in agricultural development, and great interest in
cooperating with international centers.

Though providing farmers with improved
technologies was considered important, equally
important was building NARS capacities to
perform efficient research. Thus the objectives of the
CIMMYT program in CAC are 1) sustainable
improvement of wheat-based cropping systems
through better technologies; and 2) improvement of

wheat research efficiency through more targeted
research programs, improved methodologies,
newer machinery, and operational support. The
structure of the program, its themes, and funding
are shown in Table 1.

Winter Wheat Breeding
Although winter wheat occupies only 30% of the
total wheat area in the southern region, its
importance cannot be overestimated. Winter wheat
is grown in highly populated areas, and its area has
increased three- to five-fold after independence, as
governments strive for self-sufficiency in grain.
Winter wheat remains a prime source of
subsistence food in rural areas of most CAC
countries. Traditionally, winter wheat breeding
programs were stronger in Kazakhstan and
Kyrgyzstan. Before 1991 wheat was a minor crop in
Tadjikistan, Turkmenistan, and Uzbekistan and,
therefore, their breeding programs were less

There is a rich diversity of wheat wild relatives in
the Caucasus, where good basic and applied wheat
research has been conducted. In view of this
diversity, it was interesting to observe what the
performance of international winter wheat
germplasm would be. The first nurseries shipped
to the region from Turkey (4th and 5th FAWWON)
numbered 300 lines and contained only 10-15 g of
seed. Within two years it was obvious that some of
the lines selected from these nurseries competed
well not only with local checks but also with the
best new lines/varieties.

Table 1. Structure of the CIMMYT program in CAC, 2000-
Germplasm development General/Economics
Spring Agronomy/
Activity/ Winter wheat Seed On-farm Economic Consulting
Country wheat shuttle production activities analysis NARS
Armenia X X X
Azerbaijan X X X X
Georgia X X
Kazakhstan X X X X X X
Kyrgyzstan X X X
Tadjikistan X X X
Turkmenistan X X
Uzbekistan X X X X X

Good performance of international germplasm in
CAC and the demand from local breeders resulted
in a substantial increase in the germplasm provided
from the Turkey-CIMMYT-ICARDA program in
Ankara and from CIMMYT-Mexico. Since 1998
eight different winter/facultative wheat nurseries,
supplemented by several spring wheat nurseries
from Mexico, have been offered to regional
programs. By 2000 approximately 4000 entries had
been delivered to the region. Local breeders have
done a tremendous job of screening and selecting
promising lines suited to local conditions.
International germplasm became the only source of
genetic variability and varieties in some countries;
in others, lines selected from international nurseries
created healthy competition with local germplasm
for direct utilization on farmer's fields and were
excellent choices as parents for crosses.

Table 2 gives a sample of the performance of a few
lines introduced in the region. Introduced
germplasm has three major advantages over local
materials: broad adaptation, high yield, and
resistance to yellow rust. It may, however, be
inferior in industrial quality. Durum wheat and
triticale introduced from Mexico also performed
extremely well and are in high demand, since there
are only a few breeding programs working on these

Several other important developments include
establishment of CAC-WWINET, a winter wheat

Table 2. Agronomic performance of winter wheat lines
selected from international nurseries in CAC.
Yield %to YR
Country Line Trial type, year t/ha LC %
Armenia SN64//SKE/2*/ANE/
3/SX/4/BEZ/SERI On-farm, 1999 8.2 157 20
Azerbaijan Prinia (Azamatly 95) On-farm, 1997-00 7.7 122 10
Georgia NS55-58/VEE Official, 1997-99 4.8 111 5
Kazakhstan BHR/AGA//TRK13 On-farm, 2000 5.0 133 10
Kyrgyzstan F1OS-1 YT, 2000 5.5 119 R
Tadjikistan PYN/BAU Official, 2000 3.3 112 10
Turkmenistan SN64//SKE/2*/ANE/
(Bitarap) YT, 1999-2000 5.3 100 20
Uzbekistan YMH/TOB//MCD/3/
LIRA (Dustlik) On-farm, 2000 5.9 108 15
ARMINO (Norman) YT, 1997-99 8.7 161 R

network linking researchers in the region, to more
efficiently address common problems and establish
better communication channels. An experiment was
launched to test what growth habit is more suitable
for the region. Preliminary data of field tests show
that isogenic lines with winter growth habit have an
advantage over spring types. Some countries
participate in the Winter Wheat East European Yield
Trial and have direct access to elite germplasm from
eastern Europe and the USA. For the first time after
the break-up of the USSR, systematic monitoring of
yellow rust and disease surveys have begun.

Spring Wheat Breeding
Wheat varieties grown in northern Kazakhstan are
similar in height, type, and spike morphology, and
possess good drought tolerance and excellent grain
quality. However, most of them are highly
susceptible to leaf rust and septoria leaf blotch, two
major diseases prevalent in the north in wet years.
The leaf rust epidemic of 2000 demonstrated that
none of 80 tested modern varieties and breeding
lines from Kazakhstan and Russia are resistant to
the pathogen.

Priorities for cooperation in the region were
identified during a joint Kazakhstan/CIMMYT
spring wheat conference in 1997. In developing
spring wheat varieties the challenge is to combine
the drought tolerance and good grain quality of
local materials with disease resistance from
Mexican germplasm in a daylength-sensitive
background. Shuttle breeding seemed most
appropriate for achieving this, because CIMMYT's
subtropical location limits full-scale development of
daylength-sensitive germplasm. The first crosses
were made in 1998 and the resulting populations
went through several cycles of selection for tall
stature, disease resistance, and daylength-
sensitivity under artificial light. The first lines from
this program will be sent to Kazkahstan and Siberia
in 2001 to be selected under local conditions for one
to two years. The best lines selected under drought
in Kazkahstan and Siberia will be utilized locally
and sent to Mexico for the next cycle of crosses and

In addition to shuttle breeding several activities are
conducted in the framework of the Kazakhstan-
Siberia Network (KASIB Network) on spring wheat
improvement with similar objectives. At the second
meeting of the network in Barnaul, Russia, in 2000,
several breeding programs indicated their
willingness to join the network, which, as a result,
will be expanded and formalized in 2001.

Until now regional cooperation on agronomy has
been limited to on-farm promotion of locally
developed wheat technology components to
improve yield and profitability based on realistic
costs of inputs and field operations. In the winter
wheat areas of Kazakhstan two years of
experimentation showed that high seeding rates
(220 kg/ha) used by farmers are not justified. There
was no yield increase compared to using 120 kg/
ha. At the same time yield increase due to fertilizer
use improved the profitability of grain production
per unit area. Similar experiments in northern
Kazakhstan proved the importance of variety,
seeding dates, and the preceding crop. Future
priorities for northern Kazakhstan will be
developing and testing zero-tillage, which is vital
in a region prone to wind erosion. In the irrigated
areas of the South, efforts will focus on adapting
bed planting and new irrigation techniques.

Improving Research Efficiency
Helping NARSs improve their research efficiency-
above all, through training-is one of the prime
goals of the CAC program. A number of national
and regional training courses have been conducted
over the last two years. Topics varied from the very
specific (use of the computer in breeding, on-farm
trials, seed production, etc.) to the more general
(agronomy, English language). The best young
scientists attend training courses in Mexico.

CIMMYT has been helping organizations such as
the World Bank, the Asian Development Bank, and
GTZ (Germany) to evaluate the agricultural
research and cereals production sector and draft
plans for change and reform. In 2000 the CIMMYT
team started a two-year project that will lead to the
establishment of a competitive grant system for
funding agricultural research in Azerbaijan.

Activities of CIMMYT economists in the region
have identified potential for future productivity
growth and assisted policy-makers to draw up
viable development plans for the wheat sector.
Some special projects (GTZ) grant funds for
machinery and equipment, while CIMMYT
provides technical advice on the types of
machinery and possible sources of supply. Finally,
wheat research programs in the region have
suffered severe funding cuts, and CIMMYT
provides operational support where possible.

CIMMYT's Advanced Wheat Improvement Course:

Opening Doors to NARS Senior Scientists

R.L. Villareal

The visiting scientist program is one of CIMMYT's
most active training efforts. Since 1966, 1,866
scientists from more than 90 countries all over the
world have come to the CIMMYT Wheat Program
for short periods, usually two to six weeks (Table
1). CIMMYT has refocused its resources towards
receiving scientists from countries with less
developed national programs, where the need for
training is more critical. By supporting these visits
each year, CIMMYT encourages personal
interaction among wheat researchers, who after
completing the course join the ranks of alumni who
make up an international research network.

At the Center, visiting scientists have a unique
opportunity to exchange ideas among themselves
and with our staff, discuss research results, and
generally strengthen the interpersonal and
professional bonds that hold the international
network together. Visitors share their knowledge
and experience with CIMMYT staff, trainees, and
colleagues from other countries through personal
contacts, group discussions, and seminars. Also,
they may select wheat, triticale, and barley seed to
be shipped to their home countries for use in their
crop improvement efforts (it should be stressed
that prior to shipping the seed is treated with
appropriate fungicides and other chemicals).

Table 1. Origin of CIMMYT's Wheat Program visiting scientists
based on regional aggregates, 1966 2000.

Sub-Saharan Africa
West and North Africa
East, South, and Southeast Asia
Latin America
Eastern Europe, Central Asia, and Caucasus
High-income countries
* Source: CIMMYT Training Database.

Visiting scientists* (no.)

Two main categories of professional visitors come to
CIMMYT: research directors and policy-makers
who come for a short orientation tour, and mid-
career, senior scientists who work directly with
CIMMYT senior scientists in on-going research
programs. These two categories are sometimes
confused when visiting scientists are selected or
their visits programmed. Of particular concern are
policy-makers or active wheat scientists who are
sent for 3-6 weeks-too short for a working
assignment and too long for an orientation tour.
Given the large number of visiting scientists who
come to the CIMMYT Wheat Program each year,
training resources are stretched to the limit. To
maximize the effectiveness of staff time and
increase cost effectiveness, the two types of training
need to be clarified.

To better distinguish between the two, this paper
will not discuss the subject of short-term visits for
research directors and policy-makers but will focus
instead on the CIMMYT Advanced Wheat
Improvement (CAWI) course given in Mexico to
mid-career, senior NARS scientists. The course was
established in an attempt to further define and more
efficiently manage the active visiting scientist
program. It should be noted that the CAWI course
is an integral part of CIMMYT's Global Project 8,
"Building partnerships through human resource

Objectives of the CAWI Course
The CAWI course has two main objectives: 1) to
impart to senior NARS scientists knowledge on the
efficient management of a germplasm improvement
program, and 2) to give NARS scientists the
opportunity to select new wheat germplasm from

the CIMMYT wheat breeding program. There is
little question that senior working scientists profit
greatly by coming to Mexico and working side by
side with CIMMYT scientists. The experience
exposes them to the most up-to-date methods and
materials available at CIMMYT, gives their work a
valuable boost, and provides valuable stimulus to
national programs. When courses are properly
programmed, a visiting scientist may spend one
and a half to two months at CIMMYT and then
return home without missing a cycle within the
national program.

Profile of CAWI Participants
The major focus of the CAWI course is on senior-
level researchers. Criteria for selecting participants
include: the candidate must be fully employed,
occupy a senior position in the national wheat
program (e.g., senior breeder or pathologist, or
genetic resources staff), have at least five years of
wheat research experience, and a working
knowledge of English.

Course Content and Logistics
The CAWI course offers participants: 1) a
combination of lectures, laboratory classes, and
field work to ensure a good balance of scientific
theory and its practical applications; 2) direct and
personal relationships with CIMMYT staff,
whereby participants learn to appreciate the
dignity of field work and the satisfaction and pride
that comes from doing this important task; 3) the
unique opportunity to come into contact and
discuss their circumstances with colleagues from
many countries; and 4) the initiation of a long
relationship with CIMMYT.

The course curriculum was developed in response
to the needs of collaborating countries. This
allowed the identification of what was needed in
terms of instructors and support staff, teaching
materials, laboratories, books, manuals, and
inputs, as well as housing, food, transportation,
and operational costs. CIMMYT's experienced
wheat training staff provided counsel on these

The exchange of germplasm is an important aspect
of this program. Visiting scientists send germplasm
to CIMMYT, and while at the Center, they can
observe the performance of their materials. In
return, they have the opportunity to select
germplasm from CIMMYT's extensive nurseries
for use in their own varietal development
programs. The concept of international
cooperation-the exchange of information and
breeding materials-is a significant component of
this course.

The advanced course is scheduled to take place
once a year or every other year, depending on
financial availability. The six-week course is
scheduled to coincide with the wheat selection/
harvest period so that participants can acquire
practical experience. Throughout the course,
participants work and interact constantly with
each other and with CIMMYT staff of all
disciplines in both classroom and field, as they
conduct research activities. The experience fosters
camaraderie between staff and participants, and
increases their confidence, knowledge,
competence, and appreciation of field activities.
Participants also acquire an appreciation for the
multidisciplinary approach to wheat improvement.

Course Venue
The CAWI course is held at the experiment stations
at El Batan and Toluca, near Mexico City, or in
Ciudad Obregon, Sonora. CIMMYT's long wheat
training experience, access to a wide array of
germplasm, infrastructure, availability of physical,
teaching, and financial resources, as well as the
involvement of a considerable number of highly
skilled, experienced wheat scientists are some of
the advantages of conducting the course in Mexico.
Participants are exposed to effectively organized
wheat crop programs that provide them with
models they may develop and adapt to their own

The First Advanced
Wheat Improvement Course

The first CAWI course was conducted from
September 4 to October 6, 2000 at CIMMYT
headquarters in El Batan near Mexico City and at
the Toluca experiment station in the State of Mexico
with the participation of six senior wheat scientists
from five countries, whose names, job titles, and
home countries are presented in Table 2. The course
ran for five weeks, including four weeks of
classroom, laboratory, and field activities and a
week for germplasm collection and special,
individualized programs. Three participants had
PhDs in plant breeding, two Master of Science
degrees, and one had a Bachelor of Science in
agriculture and the title "Professor." Four of them
worked on spring wheat breeding, and the other
two on winter/facultative wheat.

Administering a written or practical test was
deemed unnecessary considering the status and
experience of the participants. We therefore used
pre- and post-training questionnaires to evaluate
the performance of participants and determine the
relevance of the course curriculum to their needs.
Participants rated themselves before and after the
course in terms of their knowledge and perception
of the importance of a range of topics. The list of 44
topics taught during the 2000 course is presented in
Table 3.

The overall average pre- and post-course
knowledge assessment scores were 2.1 and 3.3,
respectively. The post-course knowledge score of
3.3 meant that our six participants felt they
possessed the skills taught during the course. On
topic assessment, mean scores of 2.7 pre-course and
3.4 post-course indicate that the participants began

Table 2. Name,job title, and home country of advanced
wheat improvement course participants, 2000.
Name Job title Country
1. Dr. Md. Abdus Samad Wheat Principal Scientific Officer Bangladesh
2. Mr. Yao Jinbao Wheat Breeder China
3. Prof. Zou Yuchun Senior Plant Breeder China
4. Dr. Minura Yessimbekova Head Cereal Crops Dept. Kazakstan
5. Mr. Dhana Bahadur Gharti Senior Scientist (Plant Pathology) Nepal
6. Dr. Kenan Yalvac Head Breeding and Genetics Dept. Turkey

the course with a good idea of which topics are
important and completed the course with a
heightened appreciation of the relevance of these
topics to their work. None of the participants
suggested additional topics to be included in future
courses. This means that the topics covered were
considered relevant and important to their wheat
own research back home. The topics that rated the
highest score (4.00) were germplasm bank, genetic
resources in breeding, management of a wheat
breeding program, and bread wheat breeding.

Table 3. Topics covered during the CIMMYT advanced
wheat improvement course, 2000.
1. World wheat situation
2. Concept and philosophy of wheat mega-environments
3. Adaptation to mega-environments
4. Germplasm bank
5. Applying genetic resources to wheat breeding
6. Managing a wheat breeding program
7. Handling segregating materials and yield trials
9. Seed production and multiplication
10. Concept and application of disease resistance breeding
11. Applying statistics to wheat research
12. Hybrid wheat development
13. Creating a successful wheat breeding program
14. Quality issues in wheat
15. Experiment station management
16. Bread wheat breeding
17. Durum wheat breeding
18. Triticale breeding
19. Barley breeding
20. Wide crosses in wheat
21. Applying physiology to wheat breeding
22. Double haploids
23. Breeding for nutrient use efficiency and toxicities
24. Sustainable cropping systems
25. Wheat "bed planting" technology
26. Synthetic bread wheats
27. Managing an international nursery operation
28. Wheat rust diseases
29. Fusarium head scab
30. Barley yellow dwarf virus
31. Septoria diseases of wheat
32. Foot rots and nematodes of wheat
33. Photoperiodism in wheat
34. Vernalization in wheat
35. Earliness in wheat
36. Physiological races of wheat rusts
37. Global impact of CIMMYT wheat research
38. Applying biotechnology to wheat improvement
39. Preparing a research proposal
40. The International Wheat Information System (IWIS)
41. Breeding for drought resistance
42. Plant nutrients
43. Breaking the yield barriers
44. Collaborative wheat breeding efforts

Five participants thought the level of instructional
materials was about right, while one found them
somewhat difficult. All participants felt the
curriculum was well planned, highly organized,
and very relevant to their current work and
responsibilities. The "Reference Manual" was
found extremely useful and informative. On the
duration of the course, three participants felt that
five weeks was about right, while the other three
felt that 6-8 weeks would be ideal. They also
commented that one week for collecting
germplasm was too short; they needed at least two
weeks to study the materials, harvest, and process
the selected materials for shipment. They all felt
that the lecture followed by demonstration/
practical teaching methodology used by most staff
was very effective. On language ability, training in
class and field, and interpersonal relations, all
participants found their trainers competent to very
competent. As for the weekly program,
participants suggested scheduling at least half a
day to interact, discuss, or follow up on topics of
special interest with staff and to use the library.

All trainees felt that the wheat improvement
technologies learned during the course were very
appropriate to home-country conditions. They also
believed their abilities as wheat scientists had
improved after the course. Their expectations in
terms of making international friends/or contacts,
collecting new reference materials and
publications, having the opportunity to travel, and
saving some money were satisfied. As for
continued support from CIMMYT, most
participants felt that receiving new publications
and returning to CIMMYT as visiting scientists
after several years would be most useful.

The participants made the following comments:

* Course curriculum was complete and covered very
important topics.
* The "lecture followed by practical application"
format employed during the course was very
* The Reference Manual very useful, informative,
and excellent pre-lecture material.

* Participants appreciated the opportunity to give a
presentation or seminar on his/her own research
* Participants appreciated having at least half a day
per week of free time to seek one-to-one
discussions with staff on specific issues and to use
the library.
They also made some valuable suggestions and
pointed out some positive aspects of the course:

* More brainstorming or discussion sessions on key
wheat improvement issues.
* More opportunities to practice special techniques
(e.g., use of IWIS and alpha lattice analysis).
* Extending the germplasm collection period to two
* Excellent schedule of field trips and weekend
* Loving and caring behavior of the organizer.
* Course organization was very good.
Finally, participants felt the advanced course is
unique and effective in increasing the expertise of
those who attend. Furthermore, they recommended
that a greater number of active scientists from
developing nations be given the opportunity to
visit Mexico and contribute to and profit from
CIMMYT's wheat research program.

Program Outlook
The need for good germplasm is obvious, as is the
need for highly trained scientists, capable of
selecting superior varieties and determining the
most adequate and efficient practices that allow
farmers to obtain stable, superior yields. Well-
trained scientists are essential to the progress of
national agricultural research programs in the
developing world. CIMMYT will continue to offer
the advanced wheat improvement course to help
NARS staff achieve their goals. The Center is also
committed to assisting national training programs
wherever and whenever possible. In conclusion,
CIMMYT's wheat training program will respond to
and anticipate the training needs of national wheat
scientists by providing opportunities tailored to
their specific circumstances.

Publications by Wheat Program Staff, 1999-2000

1. Acevedo, E.; Silva, P; i I l 1I1 1, R.; Mujeeb-Kazi, A.
1999. Bread wheat, durum wheat, and synthetic
hexaploid wheat in saline and non-saline soils.
Mexico, DF (Mexico): CIMMYT. v, 24 p. Series: CIMMYT
Wheat Special Report (WPSR) No. 49.
2. Amsal Tarekegne; Tanner, D.G.; Taye Tessema; Chanyallew
Mandefro. 1999. A study of variety by management
interaction in bread wheat varieties released in
Ethiopia. In: Regional Wheat Workshop for Eastern, Central
and Southern Africa, 10; University of Stellenbosch, South
Africa; 14-18Sep 1998. Addis Ababa (Ethiopia): CIMMYT. p.
3. Asefa Taa; Tanner, D.G.; Duga Debele; Yesuf Assen. 1999. On-
farm evaluation of fertilizer response of two
recently-released bread wheat varieties in
Ethiopia. In: Regional Wheat Workshop for Eastern, Central
and Southern Africa, 10; University of Stellenbosch, South
Africa; 14-18Sep 1998. Addis Ababa (Ethiopia): CIMMYT. p.
4. Bedada Girma; Zewdie Alemayehu; Balcha Yai; Payne, T.S.;
Amsal Tarekegne. 1999. Evaluation of introduced
bread wheat germplasm under Ethiopian
conditions. In: Regional Wheat Workshop for Eastern,
Central and Southern Africa, 10; University of Stellenbosch,
South Africa; 14-18 Sep 1998. Addis Ababa (Ethiopia):
CIMMYT. p. 553-556.
5. Bekele Hundie Kotu; Verkuij, H.; Mwangi, WM.; Tanner, D.G.
Adoption of improved wheat technologies in
Adaba and Dodola Woredas of the Bale highlands,
Ethiopia. Mexico, DF (Mexico): CIMMYT / EARO. In press.
6. Belay Simane; Tanner, D.G. 1999. Yield potential and
weather risk associated with wheat production in
Ethiopia. In: Regional Wheat Workshop for Eastern, Central
and Southern Africa, 10; University of Stellenbosch, South
Africa; 14-18Sep 1998. Addis Ababa (Ethiopia): CIMMYT. p.
7. Cakmak, I.; Braun, H.J. Zinc deficiency and genotypic
variation in zinc efficiency in wheat. In: Application of
.' ).'. -.11I, to 11 li it :Pi atiii.. Reynolds, M .P; Ortiz-
Monasterio, I.; McNab, A., (eds.). Mexico, DF (Mexico):
CIMMYT. In press.
8. Crossa, J.; Skovmand, B. 2000. Selecting wheat
accessions for germination tests. In: ICIS International
Crop Information System: Technical Development Manual
version 6. Mexico, DF (Mexico): CIMMYT / IRRI. p. 19.15-
I', I ,ii" i i, ,, 19.2
9. DeLacy I.H.; McLaren, C.G.; Fox, PN.; White, J.W; Trethowan,
R.M. 2000. The genealogy management system. In:
ICIS International Crop Information System: Technical
Development Manual -version 6 Mexico, DF (Mexico):
CIMMYT/ IRRI. p. 2.1-2.38.
10. Diaz de Ackermann, M.; Kohli, M.M.; Ibanez, V. 1999.
Septoria tritici resistance of wheat cultivars at
different growth stages. In: Septoria and Stagonospora
Diseases of Cereals A Compilation of Global Research.
,"' ,,,'iIl t, i,. rl ola, o.fl ,il l f ,l .lh; I /rl l l. l,, F
(Mexico); 20-24 Sep 1999. Ginkel, M. van; McNab, A.;
Krupinsky, J., (eds.). Mexico, DF (Mexico): CIMMYT. p. 131-
11. Gilchrist, L.; Velazquez, C.; Crossa, J. 1999. Analysis of
the septoria monitoring nursery. In: Septoria and
:r.iiv ,i'i l '. I'l". ." 'r r-i r .Ml: A Compilation of Global

D.E (Mexico); 20-24 Sep 1999. Ginkel, M. van; McNab, A.;
Krupinsky, J., (eds.). Mexico, DF (Mexico): CIMMYT. p. 59-

12. Gilchrist, L.; Gomez, B.; Gonzalez, R.M.; Fuentes, S.; Mujeeb-
Kazi, A.; Pfeiffer, W H.; Rajaram, S.; ...I"-i.1p, r 'i .i -i, ,I1
B.; Van Ginkel, M.; Velazquez, C. 1999. Septoria tritici
resistance sources and breeding progress at
CIMMYT, 1970-99. In: :,',.'.i .'ind ,..i..i".l,.i
Diseases of Cereals: A Compilation of Global Research.
"I Ihl, bl. 'i itl o .i i'.m i.t l LI''A ti'.p '-,A l ,' I' F
(Mexico); 2024 Sep 1999. Van Ginkel, M.; McNab, A.;
Krupinsky, J., (eds.). Mexico, DF (Mexico): CIMMYT. p. 134-
13. I.., I,. li.p, i l Rajaram, S.; Van Ginkel, M. 1999.
Selecting wheat for resistance to Septoria/
Stagonospora in Patzcuaro, Michoacan, Mexico. In:
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176. Ahmad, J.; Delgado, R.; Cano, S.; Mujeeb-Kazi, A. 2000.
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178. Cortes, A.; Rosas, V; Cano, S.; Delgado, R.; Zhang, J.; Li, X.;
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179. Diaz de Leon, J.L.; Zavala, R.; E .. ininiiiiiII R.; Mujeeb-Kazi,
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180. Diaz de Leon, J.L.; Mujeeb-Kazi, A.; Villareal, R.L. 1999.
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F2 plant-derived bulk-selected families of spring
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depressions measured in F3, F5, and F6
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181. Diaz de Leon, J.L.; Mujeeb-Kazi, A.; Villareal, R.L. 1999. Salt
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182. Diaz de Leon, J.L.; E.. |iIin Iit R.; Zavala, R.; Mujeeb-Kazi,
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protocol and the performance of a tester set of
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183. Dubin, H.J. 1999. The CIMMYT Wheat Program in
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184. Henry, M.; Cortes, A.; Rosas, V.; Delgado, R.; Mujeeb-Kazi, A.
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185. Lopez Cesati, J.; Villareal, R.L.; Mujeeb-Kazi, A. 1999.
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186. Mergoum, M.; Pfeiffer, WH. 1999. Advances in triticale
grain yield. Triticale Topics (16) : 18.
187. Mergoum, M.; Pfeiffer, WH. 1999. Mixtures in triticale:
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188. Mergoum, M.; Pfeiffer, WH. 1999. White grain triticale:
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189. Mezzalama, M.; Nicol, J.M.; Sayre, K.D.; Grace, P 2000.
Current progress in assessing the long term
implications of conservation tillage cropping
systems on wheat and maize root diseases and
yield in six trials at CIMMYT, Mexico. Annual Wheat
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190. Morgounov, A.I.; Karabaev, M.K. 2000. CIMMYT Items
from Pakistan. Annual Wheat Newsletter 46: 67-69.
191. Mujeeb-Kazi, A.; Gilchrist, L.; Fuentes Davila, G.; Velazquez,
C.; Delgado, R. 1999. Advanced derivatives from
bread wheat/D-genome synthetic hexaploid
combinations resistant to Helminthosporium
sativum. Annual Wheat Newsletter 45 : 108-110.
192. Mujeeb-Kazi, A.; Cortes, A.; Rosas, V.; Delgado, R. 2000. A
BC1 self-fertile intergeneric combination and the
spontaneous production of alien multiple disomic
chromosome additions. Annual Wheat Newsletter 46: 75-
193. Mujeeb-Kazi, A.; Fuentes Davila, G.; Delgado, R.; Rosas, V;
Cano, S.; Cortes, A.; Juarez, L.; Sanchez, J. 2000. Current
status of D-genome based, synthetic, hexaploid
wheats and the characterization of an elite subset.
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194. Mujeeb-Kazi, A.; Fuentes Davila, G.; Gilchrist, L.; Velazquez,
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hexaploids with multiple biotic stress resistances.
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195. Mujeeb-Kazi, A.; McLean, S.D.; -, i, ini ..1i Delgado,
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of germ plasm for detecting the location of the
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196. Mujeeb-Kazi, A.; Cano, S.; Rosas, V; Delgado, R. 1999.
Doubled haploid-mediated gene pyramiding among
some D-genome synthetic hexaploids for
Helminthosporium sativum resistance. Annual Wheat
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197. Mujeeb-Kazi, A.; Fuentes Davila, G. 1999. Elite 'bread
wheat/D-genome synthetic hexaploid' germ plasm
resistant to Karnal bunt. Annual Wheat Newsletter 45:
198. Mujeeb-Kazi, A.; Gilchrist, L.; Fuentes Davila, G.; Velazquez,
C.; Delgado, R. 1999. Fusarium graminearum
resistance in alien germ plasm and in bread
wheat/alien species derivative with multiple biotic
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199. Mujeeb-Kazi, A.; Cano, S.; Rosas, V; Delgado, R. 1999.
Helminthosporium sativum-resistant double
haploid lines derived from bread wheat/D-
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45 : 110.
200. Mujeeb-Kazi, A.; Rosas, V; Delgado, R. 2000.
Intergeneric F1 hybrids of some bread wheat
cultivars with annual and perennial Triticeae
species: Germplasm status and utilization in
wheat breeding. Annual Wheat Newsletter 46 : 71-73.
201. Mujeeb-Kazi, A.; Gilchrist, L.; Delgado, R. 2000. New
synthetic hexaploids and a set of bread wheat/
synthetic hexaploid derivatives as sources for
scab resistance. Annual Wheat Newsletter46: 81-82.
202. Mujeeb-Kazi, A.; Skovmand, B.; Henry M.; Delgado, R.;
Cano, S. 2000. New synthetic hexaploids (Triticum
dicoccum/Aegilops tauschii): Their production,
cytology and utilization as a source for Russian
wheat aphid resistance. Annual Wheat Newsletter46:
203. Mujeeb-Kazi, A.; Rosas, V; Delgado, R. 2000. Perennial
intergeneric F1 hybrids of durum wheat cultivars
with alien Triticeae species: Germplasm status and
use in breeding. Annual Wheat Newsletter 46: 70-71.
204. Mujeeb-Kazi, A.; Delgado, R.; Cano, S. 2000. Practical
applications of a gene pyramiding strategy with D
genome-based synthetic hexaploids for two major
biotic stress resistance: Wheat head scab and spot
blotch. Annual Wheat Newsletter 46: 82-83.
205. Nicol, J.M.; Mujeeb-Kazi, A. 2000. Exploiting synthetic
hexaploids for improving wheat resistance to
Crown rot (Fusarium graminearum group 1) and
common root rot (Bipolaris sorokiniana). Annual
Wheat Newsletter 46: 93-95.
206. Ortiz Monasterio, M.M.; Nicol, J.M. 2000. Cultivar
susceptibility to the root-lesion nematode
Pratylenchus thornei and wheat yield loss in the
State of Sonora, Mexico and wider implications.
Annual Wheat Newsletter 46: 95-97.
207. Pfeiffer, II I i i... II Ini, K.D. 1999.
Performance of triticale hybrids. Triticale Topics (16):
208. Pfeiffer, II i I I .... I I I. Lukazewsk, A.
1999. Performance of triticale substituted lines.
Triticale Topics (16) : 19-20.
209. Trethowan, R.M.; Van Ginkel, M.; Mujeeb-Kazi, A. 2000.
Performance of advanced bread wheat x synthetic
hexaploid derivatives under reduced irrigation.
Annual Wheat Newsletter 46 : 87-88.
210. Villareal, R.L.; Banuelos, 0. 1999. A report on CIMMYT
1998 Wheat Improvement Training Course. Annual
Wheat Newsletter 45: 99.
211. Villareal, R.L.; Banuelos, 0.; Sayre, K.D.; Van Ginkel, M.;
Mujeeb-Kazi, A. 1999. Waterlogging tolerance of
synthetic bread wheats under field conditions.
Annual Wheat Newsletter 45 : 101-102.

212. Banuelos, 0.; Villareal, R.L. Evaluacion de trigos
harineros sinteticos (Triticum turgidum x Aegilops
tauschii) bajo limitacion de humedad. Paper presented
at the Simposio Internacional, 4; y Reunion Nacional sobre
Apii. io, irn. ,.tllie 5. Memories; Morelia, Michoacan
(Mexico); 2427 Oct 1999.
213. Braun, H.J.; Payne, T.S.; Morgounov, A.I.; Van Ginkel, M.;
Rajaram, S. Wheat breeding for the next century.
Paper presented at the Proceedings of the Symposium on
Species>; Vila Real, Portugal; 6-18 Nov 7999.

214. Calderini, D.E; Reynolds, M.P Effect of degraining
treatments at pre- and post- anthesis in synthetic
hexaploid lines of wheat (Triticum durum x T.
tauschii) I i,,, p ,,' 'I' I I h i i I,,,,,,,, ir, 1999
I i '... ,' .i ,I ... Utah (USA); Oct3 -Nov
4 1999; Madison, WI (USA); ASA/CSSA/SSSA.
215. Campero C., M.; Wall, PC. Efectos del rastrojo en la
superficie del suelo sobre el balance hidrico y el
rendimiento. Paper presented at the Congreso Nacional de
la Ciencia del Suelo, 1; La Paz Bolivia; 28-30Jul 1999.
216. Cukadar, B.; Van Ginkel, M.; Rajaram, S. Hybrid wheat
research at CIMMYT. Paper presented at the Proceedings
India CIMMYT Day 18Apr 1998. In press.
217. Gilchrist, L.; Velazquez, C.; Vivar, H.E. Evaluacion de
resistencia a fusariosis de la espiga en la
poblacion haploides doblados REGLA. Paper presented
at the Congreso Latinoamericano de Cebada 3; Bastion del
Carmen, Colonia, '"..', t Oct 7999. Resumenes.
218. He, Z.H.; Van Ginkel, M.; Rajaram, S. Progress of
China/CIMMYT Cooperation on shuttle breeding
and germplasm exchange aimed at combining high
yield with resistance to scab. Paper presented at the
,.~ ,, I-i., I, i :.' i/2000. In press.
219. Hobbs, PR.; Singh, Y; Gir, G.S.; Lauren, J.G.; Duxbury J.M.
Direct seeding and reduced tillage options in the
rice-wheat systems in Indo-Gangetic Plains of
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220. Kohli, M.M.; Annone, J.G.; Garcia, R. Germoplasma de
trigo especificamente adaptado a siembra direct:
Analisis de factibilidad. Paper presented at the Congreso
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221. Meisner, C.A.; Sufian, A.; Ahmed, S.M.; Baksh, E.; Smith,
M.; I ii.. I... II Razzaque, M.A.; Shaha, N.K. W hole
family training progress within Bangladesh during
the past decade. Paper presented at the Workshop on
222. Rajaram, S.; Kohli, M.M. Production potential of
wheat and other winter cereals. Paper presented at
the National Wheat Research Conference EMBRAPA/TRIGO;
Passo Fundo, Brazil; 2528 Oct 1999.
223. Reeves, .G.; Ransom, J.K.; Sayre, K.D.; Hobbs, PR.;
Cassaday K.A. From scarcity to security: A global
perspective on weed science and the future food
situation. Paper presented at the International Weed Science
Congress- IWSC, 3. Global Weed Problems: Local and Global
Solutions for the Beginning of the Century; Foz do Iguassu,
Brazil; 6-11 Jun 2000 In press.
224. Reeves, .G.; i.lnI.i..n I Ortiz-Monasterio, I.;
Banziger, M.; Cassaday K.A. Removing nutritional
limits to maize and wheat production: A
developing country perspective. Paper presented at the

Sydney, Australia; 3-7 Dec 2000 In press.
225. Riley W J.; (,I, I 1..I 1. .. I 1, ..1 i Applying a
mechanistic model of nitrogen cycling (NLOSS) to
reduce N losses in an intensive agricultural
system. Paper presented at the I. I .. i,,, i 1. .
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Meeting In press.
226. Rivoal, R.; Valette, S.; Bel L I I I I I I .11
Gauthier, J.P; Javier, J.; Nicol, J.M. Identification and
variability for virulence to Triticeae of CCN
populations from Mediterranean regions. Paper
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Israel 1999.

227. Sayre, K.D. Effects of tillage, crop residue
retention and nitrogen management on the
performance of bed-planted, furrow irrigated
spring wheat in northwest Mexico. Paper presented
at the Conference of the International Soil iit.r Ft'e.ii, i
Organization, 15; Fort Worth, Texas, USA; 27 Jul, 2000.
228. Tovar-Soto, A.; Cid del Prado-Vera, I.; Nicol, J.M.; Evans, K.;
Sandoval Islas, J.S.; Martinez-Garza, A. Nematodos
formadores de quistes (nfq) (Nemata:
heteroderidae) en cereales de los valles altos de
Mexico: Taxonomia, distribution y densidad de
poblacion. Paper presented at the Annual Meeting of the
i 'iI.iIr..i,, ,I N' lVril.,n,, l a''' ,, r~i i( t l .l I nM ,.1 17; Auburn,
Alabama (USA); 16-20Apr2000.
229. Vivar, H.E.; Gilchrist, L.; Velazquez, C.; Hayes, PM. El
origen y desarrollo de una iniciativa de
mejoramiento en cebada para Latinoamerica. Paper
presented at the Congreso latinoamericano de Cebada, 3;
Bastion del Carmen, Colonia, O', .. Oct 999.
230. Wall, PC.; Campero C., M.; Calle C., C.; San Martin, R.
Efectos de la retencion de rastrojos y la siembra
direct en pequenas propiedades en Bolivia. Paper
presented at the Curso sobre la Siemhra Directa en Pequenas
',, 1 i 12-14 Oct 1999.
231. Wall, PC.; Campero C., M.; Calle C., C.; San Martin, R.
Experiencias con la cobertura con rastrojos y la
siembra direct en los valles interandinos de
Bolivia. In: Memorias del Encuentro latinoamericano de
Traccion Animal, 3; Cochabamba, Bolivia; 8-12 Nov 1999. p.
232. Wall, PC. El future de la fertilidad de los suelos en
Santa Cruz. Paper presented at the Congreso de la Soya;
Santa Cruz, Bolivia; -6 Mar 1999.
233. Wall, PC. Introduccion a la siembra direct. Paper
presented at the Curso de Siembra Directa en Pequenas
Propiedades; Cochabamba, Bolivia; 2-4 May 2000.
234. Wall, PC. Tecnicas para almacenar agua en el
suelo: Labranza conservacionista. Paper presented at
the Ciclo de Conferencias '...I .' -.. i ,.. .i :l ,,. I.,
delAguar>; Santa Cruz, Bolivia; 5Ago 1999.
235. Wall, PC. Un analisis de la adopcion de siembra
direct en Santa Cruz, Bolivia. Paper presented at the
Taller de Siembra Directa; Filadelfa, Paraguay; 8-11 Feb
236. Wall, PC. Un analisis de la adoption de siembra
direct en Santa Cruz, Bolivia. Paper presented at the
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Mexico; 21 -23 Oct 1999.

237. Abdalla, O.S.; ii i 1 11, ii1, I I Ocampo, B.;
Jlibene, M.; Deghais, M. 2000. Adaptation and yield
stability of spring bread wheat in West Asia and
North Africa (WANA) region. i I...i. if 1, I.
S1. 1.1 I ,. 1.i 'I,,, 92; Minneapolis, MN (USA); 5-9 Nov
2000. Madison, WI (USA): ASA / CSSA / SSSA. Abstract
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New trends in winter wheat breeding in
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International Wheat Conference, 6; Budapest ',in ..I' I
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239. Badaruddin, M.; Meisner, C.A.; Amin, M.R.; Ahmed, M.;
Pfeiffer, W.H. 1999. Use of facultative triticale as
dual purpose fodder-grain. i1 .. '.n.,.... I, I I
1999 Annual Meeting, ,I .I I i Utah (USA); Oct31
Nov4 999. Madison, WI (USA): ASA / CSSA / SCSA. p.
151. Abstract only

240. Banuelos, 0.; Villareal, R.L.; Delgado, R.; Mujeeb-Kazi, A.
1999. Direct vs. reciprocal crosses of Triticum
turgidum / Aegilops tauschii and synthetic
hexaploid / T. aestivum. ,n i. .... ...I. ti I, I 1 999
i Ili --it... ~ .. Utah (USA); Oct31-Nov
4 1999. Madison, WI (USA): ASA / CSSA / SCSA. p. 70.
Abstract only
241. Beem, J. van; Van Ginkel, M.; Rajaram, S. 2000.
Differences in the development rate of CIMMYT
wheats adapted to irrigated, rain-fed, and semi-
arid environments. In: Wheat in a Global Environment.
International Wheat Conference I 'I 1 I iln,., ,It
Jun 2000 Abstracts of oral and poster presentations. Bedo, Z.
(ed.). M artonvasar I ,ni I I, i1, 1 1"lh 1 1ii 1, 1, 1, i n hh h
of i, 11nI,1i .. i.. 1 1 f, Sciences. p. 281. Abstract only
242. Braun, H.J.; Payne, I.S.; Mergoum, M.; Van Ginkel, M.;
Pfeiffer W.H.; Rajaram, S. 2000. International
collaboration on wheat improvement. In: Wheat in a
Global Environment International Wheat Conference, 6;
O.I'. I l in.,. ~ i )00 Abstracts of oral andposter
presentations. Bedo, Z., I l I I .1 i i n III IIIIln ,I
Agricultural Research Institute of in 11fni,, n .n ..1. i f
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243. Calderini, D.F; Cavin, R.; Abeledo, L.G.; Reynolds, M.P;
Slafer, G.A. 2000. The importance of the period
immediately preceding anthesis for grain weight
determination in wheat. In: Wheatin a Global
Environment International Wheat Conference, 6; Budapest,
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presentations. Bedo, Z., l I 1111 .1 11, i IIn.I 1 I
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Sciences. p. 78. Abstract only
244. Cukadar, B.; Pena, R.J.; Van Ginkel, M. 2000. Yield
potential and bread-making quality of bread
wheat hybrids produced using genesis, a chemical
hybridizing agent. In: Wheat in a Global Environment.
International Wheat Conference, It'. -., i ,., I.t )i
Jun 2000 Abstracts of oral and poster presentations. Bedo, Z.
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of in, ,Iln1 i .i i..i 1. I, f .. Sciences. p. 50.
245. Delgado, R.; Rosas, V; Skovmand, B.; Mujeeb-Kazi, A.
1999. Production and cytology of Triticum dicoccum
based synthetic hexaploids (2n=6x=42, AABBDD).
1 I,,....in I. It .. 1999 Annual Meeting, 91; Salt take
City Utah (USA); Oct31 Nov4 1999. Madison, WI (USA):
ASA / CSSA / SCSA. p. 72. Abstract only
246. He, Z.H. 2000. Wheat quality requirements in
China. In: Wheat in a Global Environment International
Wheat Conference, -i I p I it..u,, ,i I. )00.
Abstracts of oral and poster presentations. Bedo, Z. (ed.).
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247. Hede, A.R.; Skovmand, B.; Bohorova, N.E. 2000. Effect of
genotype and growing medium on primary triticale
production. In: Wheat in a Global Environment International
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Abstracts of oral and poster presentations. Bedo, Z. (ed.).
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248. Henry M.; Skovmand, B. 2000. Identification of
wheat germplasm with combined tolerance to
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249. 1,,,, 1, .I I Khairallah, M.M.; Van Ginkel, M. 2000.
Use of molecular markers in selecting for
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250. Hunt, L.A.; Yan, W; Sayre, K.D.; Rajaram, S. 2000.
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251. Ibrahim, O.H.; Abdalla, O.S.; Abdel-Shafi, A.A.; Mossad,
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252. Kanampiu, EK.; Friesen, D.K.; Ransom, J.K.; Kabambe, VH.;
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253. Ketata, H.; Yahyaoui, A.H.; Jarrah, M.; Braun, H.J.;
Mergoum, M.; Cetin, L.; Dusunceli, F 2000. Slow rusting
in winter and facultative wheat infected with
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254. Maes, B.; Irethowan, R.M.; Reynolds, M.P; Van Ginkel, M.
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255. Mergoum, M.; Braun, H.J.; Nicol, J.M.; Bagci A.; Ekiz, H.;
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performance of spring bread wheat F1S and its
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258. Mujeeb-Kazi, A.; Delgado, R.; Fuentes Davila, G.; Gilchrist, [.;
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turgidum / Aegilops tauschii derivatives with
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259. Mujeeb-Kazi, A.; Cortes, A.; Rosas, V; William, M.D.H.M.;
Delgado, R. 1999. Cytogenetic manipulation of
tertiary gene pools species for bread wheat
improvement. 1, i i .. ...... t. li1, 7999 Annual
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260. Mujeeb-Kazi, A.; Skovmand, B. 2000. Primary gene
pool genetic diversity for wheat improvement. In:
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261. Mujeeb-Kazi, A.; Skovmand, B. 2000. Utilization of
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262. Nicol, J.M.; Rivoal, R.; Trethowan, R.M.; Van Ginkel, M.;
', i I......, 11 "nII. R.R 2000. CIMMYT'S approach to
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263. Nicol, J.M.; Ortiz-Monastero, I. 2000. Screening for
resistance and tolerance against the root lesion
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264. Nicol, J.M.; Mujeeb-Kazi, A. 2000. Synthetic
hexaploids: Offering new sources of resistance
against crown rot Fusarium graminearum group
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265. Ortiz-Monasterio, I.; Pena, R.J.; Pfeiffer W.H. 2000. Grain
yield and quality in CIMMYT's durum wheat under
water and nitrogen stresses. In: Wheatin a Global
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266. Pfeiffer, WH.; Sayre, K.D.; Reynolds, M.P; Payne, T.S.
2000. Increasing yield potential and yield stability
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267. Rajaram, S. 2000. Prospects and promise of wheat
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268. Reeves, i.G.; i,.1 ii I I Rajaram, S.; Cassaday K.A.
2000. Crop and natural resource management
strategies to foster sustainable wheat production
in developing countries. In: Wheatin a Global
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269. Reynolds, M.P; Ortiz-Monasterio, I. 1999. Effect of zinc
application in ameliorating drought stress in
w h e a t i 1.. ,. i .. I 1 i- 1 :.' .. ., '
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WI (USA): ASA / CSSA / SSSA. p. 91. Abstract only
270. Reynolds, M.P; Calderni, D.F; Condon, A.G.; Rajaram, S.
2000. Physiological basis of yield gains in wheat
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271. Salgado, M.; IIi. ..iii, 1i Mezzalama, M.; McLean,
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272. Singh, R.R; Huerta Espino, J.; Rajaram, S.; Crossa, J. 2000.
Grain yield and other traits of tall and dwarf
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273. Skovmand, B.; Warburton, M.; Rajaram, S.; Van Ginkel, M.
1999. Differentiating sibling lines of the
'Bobwhite' family using fingerprinting and
morphoagronomic characteristics. In: Agronomy
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274. Skovmand, B.; Reynolds, M.P; '' 11 2000. Mining
wheat germplasm collections for yield enhancing
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275. Skovmand, B.; 1.1 I I I 1999. Parentage of a
historical set of CIMMYT wheats. In: Agronomy
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276. Tahir, I.S.A.; Abdalla, O.S.; Elahmadi, A.B.; Ibrahim, A.S.
2000. Wheat breeding for hot environments: Traits
associated with yield improvement under heat
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277. Trethowan, R.M.; Pena, R.J.; Van Ginkel, M. 2000.
Breeding for grain quality: A manipulation of gene
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278. Trethowan, R.M.; ,iiilli i i Van Ginkel, M. 2000.
Coleoptile length of Rhtl and Rht2 isogenic pairs
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279. Van Ginkel, M.; Trethowan, R.M.; Ortiz-Monasterio, I.;
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presentations. Bedo, Z., II, 1 i Ih .. ii I 1 .
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280. Veiz, 0.; Braun, H.J.; Bedo, Z. 2000. Plant damage
after freezing, and the frost resistance of
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Environment International Wheat Conference, 6; Budapest,
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presentations. Bedo, Z., II, 1 i I I. i 1i I .
Agricultural Research Institute of in iiiuni. 1 111 1. i f
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281. Villareal, R.L.; Sayre, K.D.; Banuelos, 0.; Cruz, J.; Mujeeb-
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hexaploids (Triticum turgidum / Aegilops
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282. Zahareva, M.; Monneveux, P; Henry M.; Rivoal, R.;
Valkoun, J.; Nachit, M.M. 2000. Evaluation of a
collection of wild wheat relative Aegilops
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sources for useful traits. In: Wheatin a Global
Environment International Wheat Conference, 6; Budapest,
i 1 1, ,in, )00 Abstracts of oral and poster
presentations. Bedo, Z., .IIi I I ii I 1
Agricultural Research Institute of in.i 11,, 1 111 1. ,i ,f
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283. Zarco Hernandez, J.; Pena, R.J.; Michelena, B. 2000.
Physical structure and biochemical composition of
gluten from durum wheat (T. turgidum L.) carrying
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Environment International Wheat Conference, 6; Budapest,
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presentations. Bedo, Z. 1, i I i II.I n i i 11i, I
Agricultural Research Institute of in iiiii u 1 1 ..I ,i,, ,f
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284. Zurek, M.; San, G. 2000. Analizando la adopcion de
tecnologias que aumentan la production y
conservan los recursos naturales (APCORE) en
Centro America usando un modelo Logit y un
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1 ll, ll I.1 1 P. loll If l1, I 1fr1 1 Phl l ll.ll.l I lI 'l 1m.II
Centroamericano para el Mejoramiento de Cultivos y Animales
(PCCMCA), 46; San Juan (Puerto Rico); 1-5 May 2000. San
Juan (Puerto Rico): PCCMCA. p. 161. Abstract only

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