Front Cover
 Synthetic hexaploid wheats
 Role of disease resistant wheat...
 Helping maize farmers face...
 Acid tolerant maize : promoting...
 Wheat in West Asia and North...
 The regional maize program for...
 Cooperation rescues seed of Latin...
 Participatory plant breeding in...
 Impacts of participatory research...
 Exploitable production potential,...
 Back Cover

Group Title: Sampling of CIMMYT impacts ...
Title: Sampling of CIMMYT impacts, 1998
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Permanent Link: http://ufdc.ufl.edu/UF00077467/00001
 Material Information
Title: Sampling of CIMMYT impacts, 1998
Series Title: Sampling of CIMMYT impacts ...
Alternate Title: Ten case studies
Physical Description: Serial
Language: English
Creator: International Maize and Wheat Improvement Center (CIMMYT)
Publisher: International Maize and Wheat Improvement Center (CIMMYT)
Publication Date: 1999
Subject: Farming   ( lcsh )
Agriculture   ( lcsh )
Farm life   ( lcsh )
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
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Table of Contents
    Front Cover
        Front cover
    Synthetic hexaploid wheats
        Page 1
        Page 2
    Role of disease resistant wheat cultivars
        Page 3
        Page 4
    Helping maize farmers face drought
        Page 5
        Page 6
    Acid tolerant maize : promoting sustainable farming on acid savannas
        Page 7
        Page 8
    Wheat in West Asia and North Africa
        Page 9
        Page 10
    The regional maize program for Central America and the Caribbean
        Page 11
        Page 12
    Cooperation rescues seed of Latin American maize landraces
        Page 13
        Page 14
    Participatory plant breeding in Southern Mexico
        Page 15
        Page 16
    Impacts of participatory research on tillage and crop establishment in rice-wheat systems in the Indo-Gangetic plains
        Page 17
        Page 18
    Exploitable production potential, the research frontier, and the wheat yield gap : Spring bread wheat in Mexico's Yaqui Valley
        Page 19
        Page 20
        Page 21
        Page 22
    Back Cover
        Back cover
Full Text

Sustainable Maize and
l If rt i, for
the Poor


Impacts, 1998:

CIMMYT's recent External Program and Management Review concluded
that the Center "conducts high quality science and has an impressive
record of achievement and impact, is well managed, and has a widely
respected and vigorous leadership. The External Review has testified to the
quality of research and its relevance and impact on the daily livelihood of
hundreds of millions of rural and urban poor."


Synthetic Hexaploid Wheats


To develop wheats with traits
that enable them to yield well
under a wide range of adverse
conditions, such as are found in
farmers' fields all over the world,
plant breeders draw upon the
genetic diversity found in the
crop itself, its cultivated relatives,
and more recently, uncultivated
species in the wild. Many of these
"wild" species possess
exceptional resistance and
tolerance to diseases and climatic

CIMMYT Activities

Since crossing wheat with other
species cannot be achieved in the
usual way, CIMMYT is applying
a technique called "wide
crossing" to bridge the natural
genetic gap between them. The
lines produced using this
technique are called "synthetic"
hexaploid (bread) wheats because
the durum wheat (Triticum
turgidum) x goat grass (T. tauschii)
crosses that give rise to them
mimic the original cross that
occurred in nature thousands of
years ago and produced the first
bread wheat. Synthetics are true
wheats that can be crossed

directly with improved wheat,
facilitating the transfer of useful
traits from alien species.


CIMMYT has so far produced
more than 600 stable synthetics
that possess a surprising range of
positive traits, including tolerance
to drought, heat, and
waterlogging. Of particular
relevance is their resistance to
diseases such as
helminthosporium leaf blotch
(HLB), septoria leaf blotch, and
Karnal bunt (KB).

Helminthosporium leaf blotch is
widely distributed all over the
world but is more prevalent in
humid and high rainfall areas. It
is the major biotic factor limiting
yields in the wheat growing areas
of the eastern Asian Subcontinent.
Synthetic hexaploid wheats have

Table 1. Synthetic hexaploid wheats
resistant to helminthosporium leaf
blotch (HLB) in Poza Rica, Mexico
Synihelic hexaploids HLB score*
CIGM 90 590 9-2
CIGM 88 1356-0B 9-2
CIGM 90 897 9-3
Bacanora (susceptible
bread wheat check) 9-9
* Using a double digit scale, where the first digit
indicates height of infection 5 = up to mid-plant
and 9 = up to flag leaf, the second digit indicates
disease severity 1 = low and 9 = leaf completely

shown exceptional resistance to
leaf blotch-for example, in
several years' testing in Poza
Rica, Mexico, a hot, humid site
(Table 1).

Septoria leaf blotch causes
problems in wheat in many parts
of the world. The disease is
capable of reducing yields by as
much as 30-40% and, in some
years, may cause millions of
metric tons of grain to be lost.
New wheat lines derived at
CIMMYT from synthetic crosses
are showing remarkable
resistance to this important
disease. For example, in 1993 and
1995, synthetics demonstrated
superior resistance to septoria
leaf blotch in Toluca, a cool,
humid environment in the central
highlands of Mexico (Table 2).

Karnal bunt is a disease that
affects the quality of wheat grain
and flour. An incidence of more
than 3% infection makes wheat

Table 2. Synthetic hexaploid wheats
resistant to septoria leaf blotch at
Toluca, Mexico

Synihelic hexaploids
Aco 89/Triticum tauschii
Altar84/T tauschii
Sca/T tauschii
(bread wheat check)

Septoria score
1993 1995
21 21
31 31
11 21

89 99

grain unfit for human
consumption. Infected wheat lots
are rejected by the milling
industry, greatly reducing
farmers' profits. To help farmers
solve this problem, CIMMYT
scientists are working on
improving KB resistance. They

Table 3. Synthetic hexaploid wheats
resistant to Karnal bunt at Cd. Obregon,

Synthelic hexaploids
Altar 84/Triticum tauschii
Altar 84/T tauschii
(susceptible bread wheat check)

0o Karnal
bunt score

have found synthetics to be the
best source of resistance, as
shown in trials conducted in
Ciudad Obregon in northwestern
Mexico, where synthetic
hexaploid wheats have displayed
superior KB resistance (Table 3).

Synthetics-or their derivatives-
are also generating major yield
gains. In yield experiments
conducted in Cd. Obregon in
1997, a synthetic hexaploid wheat
derivative out-yielded other high-
yielding wheat lines (Figure 1).

Yield t/ha



1945 1955 1965 1975 1985 1995
Year variety was released
Figure 1. Yield vs. year of release, 1996-97 cycle, Ciudad Obregon, Mexico.

Role of Disease Resistant Wheat Cultivars


Until a quarter of a century ago,
wheat rusts, the most serious and
economically important diseases
of wheat, periodically devastated
food production. This happened
every time that susceptible
varieties, favorable
environmental conditions, and
pathogen adaptability combined
to create large-scale epidemics. A
real solution, rust resistant plants,
became possible with the advent,
early in this century, of
systematic plant breeding for
disease resistance.

CIMMYT Activities

Starting in the 1950s, the
CIMMYT Wheat Program (or
rather, its predecessor, the Office
of Special Studies) used in its
breeding efforts the durable stem
rust resistance in Hope, a variety
bred by McFadden in the USA,
and the durable leaf rust
resistance in Frontana, a Brazilian
variety. Since then, the Program
has continued to improve
resistance by broadening the
diversity of sources of resistance
to rust pathogens.

Based on CIMMYT's research
over the last 30 years, our
national program partners have
released more than 500 bread
wheats that trace their durable
rust resistance to Hope, Frontana,
and other, diverse sources. This
resistance is conferred by minor
genes that interact additively to
protect the crop from rust
pathogens. Most importantly, the
resistance conferred by minor
genes is durable because it allows
the disease to develop slowly and
at a low intensity that has a
negligible effect on yields.


Farmers all over the world have
reaped the economic benefits of
disease resistant cultivars, which
produce the same yield with and

Yield t/ha

without fungicide protection-for
example, in Mexico's Yaqui
Valley (Figure 1). When farmers
plant disease resistant cultivars,
they apply less fungicide, reduce
their production costs, and lessen
the damage done to the

In a recent study on the benefits
of incorporating leaf rust
resistance into modern bread
wheats, CIMMYT economist
Melinda Smale estimates that
gross benefits generated in the
Yaqui Valley from 1970 to 1990
through the incorporation of
disease resistance totaled US$ 17
million (in 1994 real terms).
Similar economic benefits seem
likely in many other wheat
producing areas of the
developing world, for example,


1960 1965 1970 1975 1980 1985 1990
Year variety was released

Figure 1. Yield of historically important varieties (released 1964-86) with and
without fungicide, Ciudad Obregon, Mexico, 1990-91.

where disease pressure is heavy
and the cost of treating disease
outbreaks is high. Smale further
points out that even when costs are
overstated and benefits understated,
the rate of internal return on
capital invested in CIMMYT's
disease resistance research is 13%,
well within the range
recommended for use in project
evaluations by the World Bank.

On a global scale, CIMMYT
Economics Program survey data
indicate that semidwarf
germplasm developed by
CIMMYT and its national research
system partners in 1977-90
contributed 15.5 million tons of
additional wheat production in
1990, valued at about US$3
billion, primarily due to varieties
with increased disease resistance.

Their performance in farmers'
fields shows fewer fluctuations
and they have not succumbed to
major rust epidemics in the last 25
years. As a result, yield stability of
modern semidwarfs has increased
on all continents. Evidence
suggests that genetic resistance,
specifically to leaf rust, may be
the most important contribution
of wheat breeding to productivity
and stability in the 1990s.

Helping Maize Farmers Face Drought


Most maize in the developing
world is grown without
irrigation, depending solely on
precipitation. Insufficient and
poorly distributed rainfall is a
major constraint to productivity,
reducing yields overall more than
15% per year (an annual grain
loss in excess of 20 million tons).
Most catastrophic for developing
country maize farmers, however,
are periodic, severe droughts that
can result in near-total crop loss.
For example, after the major
drought of 1991/92 in Eastern
and Southern Africa,
approximately US$ 800 million in
food aid was needed to stave off
starvation, export deficits soared
from reduced agricultural
production, and some countries
have yet to recover economically
or socially. Particularly afflicted
are poor rural inhabitants who
scratch out a living at the margins
of subsistence.

CIMMYT Activities

CIMMYT researchers found a
simple yardstick for identifying
and improving drought tolerance
in maize. In essence, they showed
that mid-season drought tends to
increase the number of days
between male and female
flowering, known as the anthesis-
silking interval (ASI), and that
this effect was tied to the
dramatic loss in productivity
under dry conditions during
flowering. Capitalizing on that
correlation, they developed a
methodology for improving the
drought tolerance of maize by
selecting for reduced ASI under
controlled drought stress. They
refined the approach through
work with the popular lowland
tropical population Tuxpefio
Crema I and several other
unrelated populations.

Impacts and Follow-up

This research resulted in a 20-40%
increase in the yields of
experimental populations under
severe mid- and late-season
drought. A valuable spin-off was

the discovery that selecting for
reduced ASI also improves the
performance of maize under low
nitrogen conditions. CIMMYT
maize breeders now regularly use
evaluation under drought to
enhance the stress performance
of maize targeted for dry areas.
To move the benefits of this
research on-farm, in 1996
CIMMYT began two major
projects with national program
partners in sub-Saharan Africa to
develop new cultivars that
combine drought and low-N
tolerance with good adaptation,
disease resistance, and desirable
grain type. Funded by the Swiss
Development Cooperation (SDC),
the United Nations Development
Programme (UNDP), the
International Fund for
Agricultural Development
(IFAD), and the Swedish
International Development
Cooperation Agency (Sida), these
efforts are already transforming
the way breeders in the region
think about their work and have
clearly demonstrated the
superiority under stress of maize
developed using this
methodology over commonly
used commercial hybrids (see

Recent performance of drought-tolerant experimental hybrids from CIMMYT compared with popular, widely
grown hybrid checks of similar maturity from southern Africa. Data are from a comparison made in Zimbabwe.
Local hybrid checks performed well when growing conditions were favorable, but their performance declined
dramatically when grown under drought-stressed conditions. Drought-tolerant maize germplasm from CIMMYT
thus demonstrates its impact potential for conditions typical for many resource-poor farmers in Africa.

Early maturing hybrids:

Growing conditions ->

Days to Oplimal
Ilowering Yield (I/ha) Rank

Severe drought
Yield (I/ha) Rank

Mean, drought-tolerant hybrids from CIMMYT
Mean, local hybrid checks

Highestyield among drought-tolerant CIMMYT hybrids 1205 2 482 1
Highestyield among local hybrid checks 1285 1 242 50

Total number of entries 100 Drought-tolerant CIMMYT hybrids comprised 93 out of the 100 entries

Late maturing hybrids:

Growing conditions -> Days to Oplimal Severe drought
flowering Yield (t/ha) Rank Yield (t/ha) Rank

Mean, drought-tolerant hybrids from CIMMYT 803 1006 109 284 107
Mean, local hybrid checks 792 11 49 55 208 144

Highestyield among drought-tolerant CIMMYT hybrids 1355 2 527 1
Highestyield among local hybrid checks 1400 1 397 17

Total number of entries 216 Drought-tolerant CIMMYT hybrids comprised 208 out of the 216 entries

Acid Tolerant Maize: Promoting

Sustainable Farming on Acid Savannas


Acidic soils account for some
four-fifths of agricultural lands in
South America and two-fifths-
more than 183 million hectares-
in Brazil alone. Normal maize
varieties yield as little as 0.5 t/ha
of grain on even moderately
acidic soils, as compared with the
average in developing countries
of just over 2.0 t/ha. Despite the
relative unsuitability of acidic
conditions for crop farming, the
demand for food from rising
populations has led to the
increased use of acidic soil areas
for agriculture. By the year 2000,
for example, some 50 million
hectares of acidic savannas in
Brazil will be under cultivation.
The continued migration of rural
populations to the cities is
placing heavy pressure on maize
producers, and demand for
maize in the region is expected to
grow 3.5-4.0% each year. Those
who stand to be most affected by
the fate of maize in Latin America
are the poor: poverty
characterizes an estimated 40% of
the region's population and more
than 60 million people are
malnourished or at serious
nutritional risk. Increased maize
production would provide more

grain at the farm level and in
urban centers, reducing the price
of food for the poorest. It would
also help relieve pressure to bring
environmentally fragile lands
under the plow and, by
improving the fortunes of
farmers, lessen migration to
urban centers.

CIMMYT Activities

Through its South American
Regional Program based at the
Centro Internacional de
Agriculture Tropical (CIAT),
CIMMYT began developing
maize that possessed tolerance to
acidic and aluminum toxic soils
in the late 1970s, demonstrating
the possibility of improving the
genetic tolerance of maize to
these constraints. In the mid-
1980s, researchers assembled sets
of maize materials with high
yield potential, tolerance to acidic
soils, and resistance or tolerance
to other key constraints, either
singly or in combination.
Subsequent work involved
recurrent selection and crossing
thousands of superior genotypes
within each population at our
regional experiment station in
Colombia, as well as in acidic
soils of Brazil, Indonesia, Peru,

the Philippines, Thailand,
Venezuela, and Vietnam, with
help from research programs in
each nation. In the early 1990s,
experimental varieties from these
populations were evaluated on
acidic and normal soils in Latin
America, Africa, and Asia in
comparison with selected
varieties submitted by national
research programs. A strong
indication of success was that the
CIMMYT genotypes out-yielded
checks by an average 33%, and an
experimental variety from this
work gave the highest yields
across all environments. In
subsequent tests, products of this
research-all open-pollinated
varieties-yielded as much as
0.7t/ha mor e than a Brazilian
hybrid under non-acidic
conditions in Colombia, showing
that the acid tolerant maize is also
productive in normal soils. In
1992 CIMMYT also initiated a
four-year project with support
from the Inter-American
Development Bank (IDB) to study
technical problems associated
with maize production on acidic
soils. A panel of international
experts praised this IDB-
CIMMYT partnership, saying that
the project had achieved all of its
objectives and more.


The most celebrated output to
date is the maize variety ICA-
Sikuani V-110, developed by the
Colombian Agricultural Research
Corporation (CORPOICA) using
acid tolerant maize generated
through the collaborative
research described above. The
variety is already sown on
thousands of hectares in its native
Colombia and is being tested for
use in neighboring countries. In
trials in farmers' fields in acidic
soil areas of Ecuador and Peru,
Sikuani consistently out-yielded

the best local varieties both under
optimal and farmer management
(see figure). Based on these
results, Peruvian authorities are
increasing seed of Sikuani for
release in that country. In similar
trials in Bolivia, Sikuani yielded
as much as the best local variety
but caught farmers' eyes due to
its outstanding plant and grain
type. Acidic soil tolerant hybrids
derived more recently from
CIMMYT's research produce as
much as 70% more grain than
Sikuani and should be of special
interest in Brazil, where many
maize farmers sow hybrids.

Grain yield (t/ha)

I nt31



Sikuani out-yields local varieties in
farmer's fields in Peru.

Wheat in West Asia and North Africa


CIMMYT Activities

West Asia and North Africa
(WANA) is a diverse ecoregion
including widely different
environments such as the
irrigated Nile Valley, the dry
Anatolian Plateau, the wet
Mediterranean coast, and the
extremely dry Atlas Mountains.
In WANA wheat is sown on 28.3
million hectares, 65% of which is
semiarid. The largest wheat
producing countries are Turkey,
Iran, Egypt, Saudi Arabia,
Morocco, and Syria (Table 1).
Depending on the location, major
environmental stresses are
drought, heat, cold, and boron
toxicity superimposed on such
adverse biological factors as
yellow rust, leaf rust, septoria
triciti leaf blotch, Hessian fly,
sawfly, and nematodes.

Table 1. Wheat production in WANA

Area, Production,
1990-92 1990-92
Country (000 ha) (000t)

Saudi Arabia



dryland wheat program develops
improved germplasm with
drought tolerance for the WANA
region. The program derives
advanced lines from CIMMYT for
testing in irrigated and high
rainfall areas of WANA.
CIMMYT has two breeders
posted with ICARDA in Aleppo,
Syria, to work on spring wheat
germplasm for drought areas.
Two CIMMYT breeders and one
ICARDA breeder are assigned to
Ankara, Turkey, a partner
country with which CIMMYT has
maintained close collaboration
for the past 25 years. These
researchers work on winter/
facultative wheats.

Growth in wheat
yields, 1983-92
-1 3
1 6

Growth in wheal
production, 1983-92
1 8

Though working in a complex
region, CIMMYT-Mexico,
ICARDA, and national program
researchers have dramatically
increased wheat yields and wheat
production in the countries of
WANA. This fruitful
collaboration has had significant
impact in the region, of which we
list the following examples:

* With the exception of Afghanistan
and Iraq, most countries in WANA
experienced high yield growth
rates in 1983-92 (Table 1). Improved
germplasm with tolerance to
drought and temperature extremes,
and resistance to prevailing
diseases and insects, was
essential to achieving these yield

* The most widely grown durum
variety in the dryland areas of
WANA is Korifla, introduced from
CIMMYT-Mexico and released in
several countries under different
names (Cham 3 in Syria, Haran in
Turkey, Petra in Jordan, Zahra 5 in
Libya, and Korifla in Algeria and
Iraq). As an example of its impact,
10 years after its release, Korifla is
being planted on 86% of Syria's
durum area, and durum wheat


production in that country has

experienced a 50% increase

(Figure 1).

+ Since 1990, 14 countries have

released about 100 varieties that

are either direct releases from

CIMMYT-Mexico, are CIMMYT/

ICARDA lines, or had a CIMMYT

line as a parent (Table 2). Farmer

adoption of CIMMYT- and

CIMMYT/ICARDA-derived varieties

in WANA continues to increase,

and today these varieties cover a

large portion of the area devoted to

wheat in the region.

+ ICARDA economists estimate that

irrigation and improved

technologies have increased

wheat production in the region 1.15

million tons per year; 0.31 million

tons (valued at about US$ 50

million) of this increase can be

attributed to improved CIMMYT-

and CIMMYT/ICARDA-derived



Table 2. Bread and durum wheat varieties released by the countries of WANA since
1990 (note that these varieties are either CIMMYT advanced lines or have CIMMYT
parents in their pedigrees)

ol release

Bread wheal

Durum wheat

Pamir 94*
Dayma 96, Ghori 96, Takhar 96, Roshan 96

Nesser, Acsad 59, Zidi Okba, Rhumel 21 AD, Soummam


Gemmeiza 1, Giza 165, Sahel 1
Giza 167, Sids 4, Sids 5, Sids 6, Sids 7, Sids 8

Dogankent 1
Tajan, Atrak, Nicknejad, Mahdabi, Darab 2

Adnanya, Hamra, Abu Ghralb


Sen 82

Bohouth 101, Bohouth 102

Achtar, Mehdia, Massira

El Neelain, Sasarleb

Cham 6, Bohouth 6

Vaga 92

Utique 96, Tebica 96

Gun 91*
Sen 82

Kasifbey, Basribey, Seyhan 95, Kana, Lira-SA, Sultan 95*

Bandirma 97, Karacabey 97, Pamukova 97, Kinaci 97*

1998 Yildiz 98

Korifla, Omrabi 6
Heider, Kabir 1, Omrabi 1, Belikh 2

Sohag III, Beni Suef I

Seimarah (Omrabi 5), Korifla, Heider

Waha Iraq
Korifla, Omrabi 5

Cham 1

Omrabi 3

Zahra 5 (Korlfla)

Jawhar, Yasmine
Anouar, Omrabi 6



Omrabi 3

Cham 1

Aydin 93
Firat 93
Ceylan 95, Salikli 95
Haran 95

Dacki, Altintoprak

S A United Arab Emirates
90 94 98 1990 Cham 2
Winter bread wheat varieties released by national programs in collaboration with CIMMYT/Turkey

Figure 1. Durum area and production in
Syria from 1970 to 1997.

1970 74 78 82 86

The Regional Maize Program for

Central America and the Caribbean


Central America and the
Caribbean is the center of origin
of maize, with highly developed
pre-Columbian slash and burn
maize-bean cropping systems.
Maize is the most important
subsistence staple for resource-
poor rural families: it is food,
folklore, culture, and tradition. It
is produced largely using
traditional, low-input
technologies that can lead to
degradation of the resource base.
The region's population of 30
million is growing at around 3%
annually, mostly in urban centers;
the demand for food is increasing
without comparable increases in
agricultural productivity or
sustainability. Most countries
import a high proportion of their
total maize needs. Seed industries
are weak, and improved seed is
used on only a fifth of the maize
area. The "lost decade" of the
1980s seriously weakened
national maize research
programs; the 1990s have
witnessed the bankruptcy and
downsizing of the public sector
without a corresponding growth
in private sector activities. This,
together with the adoption of
inappropriate macroeconomic
policies, has exacerbated the

already considerable difficulties
of most smallholder farmers, at
least for the short term.

CIMMYT Activities

Since its inception, CIMMYT has
assisted national programs in
Central America and the
Caribbean, initially providing
improved germplasm and in-
service training. As of the mid-
1970s, the center has supported
and participated in the Regional
Maize Program for Central
America and the Caribbean
(Programa Regional de Maiz, or
PRM), a collaborative network
involving nine national
agricultural research programs,
with long-term funding from the
Swiss Development Cooperation
(SDC). With the principle aim of
increasing productivity while
preserving or improving the
natural resource base, the PRM
1) develops open-pollinated
varieties and hybrids with
improved performance under the
main biotic/abiotic stresses of the
region, as well as high-yielding
hybrids for favorable
environments; 2) generates and
validates improved crop
management practices; and
3) conducts socioeconomic
research on technology changes

relating to PRM objectives. The
PRM is a model network that
empowers national program staff
and motivates them to excellence;
notably integrates breeding,
agronomy, and socioeconomics;
sets its agenda through a formal,
objective, democratic, annual
process; conducts clearly
targeted, strategic research;
produces high quality scientific
reports; establishes productive
partnerships with leading
international centers, regional
institutions, and non-government
organizations (NGOs); and
generally provides scientific and
institutional leadership. CIMMYT
contributions to the PRM-seed,
science, and the enthusiasm and
talents of a progression of
technical advisors-have gained
the Center recognition,
appreciation, and trust


The following point summary is
by no means an exhaustive
accounting of accomplishments,
but lists several that have
significantly improved the
livelihoods of smallholder maize
farmers in Central America and
the Caribbean.

* Improved germplasm. Since the
1960s, more than 100 improved
varieties or hybrids of maize have
been released in Central America
and the Caribbean, many that
possess tolerance to key
production constraints, and nearly
nine-tenths containing genetic
contributions from CIMMYT
breeding or germplasm bank

* Corn stunt tolerant maize for
Nicaragua. In Nicaragua's Pacific
region, 60% of the total area and
80% of farmers (80-100,000 ha) use
NB6 or NB12, PRM cultivars with
tolerance to corn stunt, a disease
that can seriously constrain
productivity and which is is
spreading quickly into Mexico and
South America. Genetic tolerance
to stunt provides yield gains of 1.0-
1.5 t/ha over susceptible cultivars,
and studies have confirmed annual
impact of U$ 3-5 million in grain
produced. The PRM has additional
sources of resistance, and is more
precisely defining this multi-
pathogen disease complex through
molecular genetics research in
collaboration with CIMMYT.

* Widespread hybrid use in El
Salvador. Of the national maize
area, 60-70% is planted to hybrids.
These out-yield open-pollinated
varieties by at least 1.0-1.5 t/ha,
bringing farmers millions of dollars
worth of additional grain each year.

* Promotion of conservation tillage
through Guaymango, El Salvador.
Guaymango is an area of 5,000 ha
with a maize-sorghum cropping
system. Adoption of the practice of
using crop residues as mulch,
rather than burning them, as well
as sowing hybrids and applying
modest levels of fertilizer, gradually
increased maize yields from 1.0 to
4.0 t/ha, while improving soil
characteristics and properties.
Guaymango has become the focal
point for the promotion of soil
conservation practices to
thousands of farmers, extension
workers, NGOs, etc., and also
hosts a yearly "conservation tillage

* Conservation tillage in Azuero,
Panama. Azuero, Panama, an area
with 10,000 ha of mechanized
maize production, was introduced
to conservation tillage through an
on-farm research course given by
CIMMYT there in 1985 (the center
also donated a minimum tillage
planter). The national program
heavily promoted the practice and,
by 1996, more than half the farmers
were using it, reducing production
costs, weed problems, herbicide
use, and soil deterioration.

+ Intercropping canavalia in
alternate rows of maize in Azuero,
Panama. A decade of research on
intercrops involving maize and the
green manure, canavalia, has

generated very promising
alternatives for Azuero, and rapid
adoption is beginning to occur.
Compared to the original system of
monocropped maize, the
intercropping systems provide a
200-500% economic return,
eliminate weeds, substitute for
non-organic fertilizers, are used to
enrich cattle fodder, and result in a
long-term improvement of soil

* Seed stock loss during Panama's
US invasion. Seed stocks of
Panama's national agricultural
research program were lost during
the US invasion in 1989. The PRM
quickly supplied remnant seed,
allowing seed production for the
upcoming season. The PRM has
generally provided national seed
security to participating countries.

* Continuity in the face of
institutional turnover. For many
years, the operational capacity of
national agricultural research
programs in the region has
declined due to resource
constraints, instability, and staff
turnover, with a clear negative
impact on research outputs.
CIMMYT and the PRM have drawn
together researchers and provided
a venue for their professional
development and long-term
productivity, thus conserving and
enhancing national research

Cooperation Rescues Seed

of Latin American Maize Landraces


Efforts to apply scientific
breeding to maize genetic
resources in the tropics, begun
under a joint Mexico-Rockefeller
Foundation endeavor in the
1940s, initially involved extensive
collecting and cataloguing of seed
samples of farmer varieties,
known as landraces, throughout
Latin America. First seen simply
as raw material for plant
breeding, the landrace seed soon
came to represent a priceless
reserve against future genetic
erosion, and collections were
stored in genebanks in the
nations of origin. Unfortunately,
budgetary constraints in the
region during the 1970-80s
critically hampered efforts of
genebank personnel to maintain
their collections properly.
Specifically, the germination
capacity of seed samples in banks
must be monitored and, when it
falls below a specified level,
viable seeds must be grown out
according to scientific guidelines.
This provides fresh samples that
represent as nearly as possible the
genetic diversity of the original-
a process known as
"regeneration." For lack of
resources, however, irreplaceable

collections of landraces, many of
which were no longer grown by
farmers and thus existed only as
seed samples, were sliding
inexorably toward extinction.

CIMMYT Activities

Latin American genebank
representatives sounded the
alarm about this situation during
a workshop at CIMMYT in the
early 1990s, based on evidence of
poor germination obtained
through the Pioneer Hi-Bred/
USDA-ARS Latin American
Maize Project (LAMP). A
CIMMYT genetic resources
specialist began working with
genebank staff from 13 nations to
mount a massive rescue effort,
with funding from USAID under
project Noah and additional aid
from the USDA-ARS National
Seed Storage Laboratory (NSSL).
As executing agency, CIMMYT
developed and submitted the
proposals, workplans, and
contracts for this ground-
breaking project. The center also
coordinated activities; furnished
technical guidance; reported to
donors on progress; and
organized a mid-term project
evaluation workshop in 1994 and

a final workshop in 1996. A
CIMMYT researcher, for example,
closely monitored regeneration
protocols to ensure they met
scientific standards, especially
the recommended minimum
yield of 100 ears for a successful
regeneration (i.e., one that
embodies nearly all the genetic
diversity of the original
accession, and thus avoids so-
called "genetic drift").

Impacts and Follow-up

Under the collaborative project,
nearly 7,000 endangered
collections were regenerated and
back-up samples stored in trust at
CIMMYT and NSSL, ensuring
their future accessibility
worldwide (see table). As a spin-
off of this effort, cooperation was
strengthened on maize genetic
resource conservation and
management in the Americas, the
center of genetic origin for maize.
Modest funding from NSSL has
allowed regeneration of
additional collections during
1997-98. Cognizant of the need to
continue this important work,
maize genetic resource specialists
regionwide will meet at CIMMYT
in summer 1998 to plan a new

initiative. Regenerating
threatened collections will surely
be on the agenda, but a key
component of future work is
effectively evaluating and, where
feasible, improving the
characteristics of landraces still
grown by farmers and of race
groupings from regenerated bank
collections to facilitate their use
by farmers, breeders, and
researchers in general.

Outcomes of collaborative efforts by
CIMMYT, national germplasm banks in
Latin America, USAID, and USDA-NSSL
over 1992-96 to regenerate endangered
seed holdings of maize landraces
Number ol
Country collections regenerated
Argentina 329
Bolivia 380
Brazil 390
Chile 297
Colombia 1,195
Cuba 101
Ecuador 348
Guatemala 304
Honduras 42
Mexico 2,714
Paraguay 84
Peru 422
Venezuela 130
Total 6,736

Participatory Plant Breeding in

Southern Mexico


Can collaborative breeding
(between farmers and crop
breeders) increase farmers'
welfare while maintaining or
enhancing genetic diversity? The
question is significant because if
farmers cannot improve either
their productivity and/or the
quality of their produce without
eroding genetic diversity, a
serious challenge is posed to
conservation approaches based
on in situ preservation of genetic
diversity (Figure 1).

CIMMYT Activities

The Economics and Maize
programs at CIMMYT, in
collaboration with INIFAP-


Household welfare

Figure 1. Starting from the G2 position,
the win-win positions of increased or
maintained diversity and/or farmer
welfare are represented by the arrows.
G1 indicates a position of increased
diversity, but less benefit to farmers,
while G3 and G4 represent in varying
degrees increased benefits for farmers
and costs to genetic diversity.

Oaxaca and with funding from
IDRC, have initiated a two-year
pilot project in the central valleys
of Oaxaca to determine factors
that affect farmers' management
of diversity, to characterize that
management, and ultimately to
use that analysis to develop tools
to advance effective farmer-
managed in situ conservation.

The recently completed first year
of field work has concentrated on
collecting benchmark data,
particularly on local landraces
and farmers' knowledge. Fifteen
communities were identified by
the project team and 153 maize
samples collected. All maize
samples have been planted at
CIMMYT's Tlaltizapan
Experiment Station for evaluation
and reproduction. Trials were
established at each of the 15
communities using the samples
plus an additional 17 historical
samples from CIMMYT and
INIFAP gene banks. Data were
collected from trials. Farmers in
the communities were invited to
evaluate crop samples and to
provide demographic,
socioeconomic, and agronomic
data at harvest (216 farmers-117
females, 99 males).


The results from the first year of
the project will essentially
provide the foundation for the
following year's work. Several
noteworthy outputs, however,
have already been achieved.

* The farmers' management of
maize diversity in the study area
has been successfully

* In addition, a functional
understanding has been
developed of the factors affecting
farmer management of maize
diversity in the study area and
their mechanisms of action. One
somewhat surprising but
extremely relevant finding is that
subsistence farming for household
consumption and the salient
preferences associated with it
outweighed even yield as the most
frequently cited positive
characteristic of varieties. Such
findings have a direct bearing on
breeder/farmer collaborations.

* The first year's research has
provided the characterizations,
logistical contacts, and initial
conceptual framework required
for the study's second phase, in

which farmers can be further
classified by their management of
diversity; technologies, skills, and
information will be identified that
can simultaneously enhance
farmers' welfare and genetic
diversity; and social organizations
and mechanisms that can support
the diffusion of these supporting
factors will be identified and better

* The ultimate impacts will be the
development of methods that:
1) assist genetic resource
specialists in selecting effective
conservation strategies; 2) enable
researchers to understand
farmers' incentives for maintaining
genetic diversity in their crops; and
3) allow researchers to assess the
impact of collaborative breeding

Impacts of Participatory Research on Tillage

and Crop Establishment in Rice-Wheat Systems

in the Indo-Gangetic Plains


CIMMYT, in partnership with the
Rice-Wheat Consortium for the
Indo-Gangetic Plains, has helped
develop improved practices for
tillage and establishment for
wheat after rice. In this region,
rice-wheat systems cover more
than 12 million hectares, and are
the foundation of food security,
employment, and income
generation for over 150 million
rural inhabitants, many of them
poor (e.g., landless laborers).
Introduced practices include
surface seeding,1 the Chinese
hand tractor,2 and several other
zero- and strip-till drills.3

CIMMYT Activities

Project funding from DFID,
USAID, and ACIAR has allowed
us to monitor these options when
managed by farmers in selected
villages. At present, farmer
experimentation on these options
covers 156 ha in 13 sites in four
countries (see table). There also
are large areas under researcher-

managed trials aimed at
understanding biophysical
processes. Impacts are beginning
to appear, but quantitative impact
studies remain to be done. Some
impacts, anticipated as well as
observed, are listed here.


On farmers-Farmers have been
astonished at the excellent
performance of the options,
especially during the current crop
season when untimely rains
delayed sowing. The new options

allowed prompt sowing (5-25
days earlier), resulting in excellent
stands and good yields (increases
of 0.5 and 2.0 t/ha) while
reducing cash costs and labor and
machinery requirements (by
about half). In some instances the
new practices made the difference
between a yield of 3 t/ha vs. no
crop at all! Farmers are excited
about possibilities for system
intensification via the new
practices-a third high value crop
(after wheat and before rice)
where previously none could be
grown. In most villages, farmers

Area under farmer experimentation, by practice and site, wheat season 1997-98
Country and site Chinese hand traclor Surface seeding Other
Chuadanga 10
Dinajpur 14 1
Netrakona 30
HAU Haryana 34
DWR Haryana 3
PAU Punjab 17
Pantnagar, UP 4
RAU, Pusa, Bihar 3 1
ARI, Patna, Bihar 4
Bhairahawa 18 6
Parwanipur 5 1
Naldung 1
Punjab 4
Total 85 9 62

1 A practice whereby pre-soaked, pre-germinated wheat seed is mixed with a slurry of water and manure, then
broadcast into a standing or recently harvested rice crop. The timing of sowing is determined by the soil moisture.
2 Including a rotovator-cum-seed drill capable of establishing wheat into standing rice stubble with a single pass of
a two-wheel tractor.
Including zero-till and strip-till drills used with four-wheel tractors, e.g., the Pantnagar drill.

plan a substantial increase in area
devoted to the new practices next

On the poor-Higher rice-wheat
system productivity-and
diversification of these systems
-will impact favorably on the
poor through employment
generation. (Rich) tractor owners
may suffer as the demand for
multiple plowings dwindles-
but demand for labor will

increase, putting pressure on
rural wages when these already
are rising.

On national research priorities-
Scientists in national research
systems have begun programs of
research on tillage and
establishment with their own
resources, and have begun to
breed rice and wheat germplasm
better suited to reduced and zero
tillage conditions.

On policymakers-The
excitement in farmers' fields has
spread in some instances to
policymakers. The Minister of
Agriculture of Nepal visited the
Bhairahawa site. State authorities
in Uttar Pradesh have purchased
an additional 100 Pantnagar drills
for farmer experimentation.

On the environment-The new
practices improve input use
efficiency and weed control,
reducing the need for herbicides
and for high doses of fertilizers.

Exploitable Production Potential, the

Research Frontier, and the Wheat Yield Gap:

Spring Bread Wheat in Mexico's Yaqui Valley


What recent trends and
relationships can be observed
between potential (research)
yields and farmer yields in the
Yaqui Valley, the high production
region where the Green
Revolution was born? And what
can these trends tell us regarding
avenues for increasing yield now
and in the future? The importance
of these questions is nearly self-
evident. Given the steady rise in
wheat demand due to population
and income growth, the challenge
for sustaining wheat productivity
is great. According to the
International Food Policy
Research Institute (IFPRI), to
meet demand, wheat productivity
growth will have to increase as

Yield (t/ha)
9 -

much over the next two decades
as it has over the past three.
Growth will have to be in both
high potential and marginal
production environments.

CIMMYT Activities and
Related Impacts

Between 1950 and 1996, spring
wheat yields in the farmers' fields
of the Yaqui Valley rose an
impressive five-fold, from
approximately 1 t/ha to 5.5 t/h
(Figure 1). Much of this increase
can be attributed to CIMMYT/
INIFAP varieties and breeding
efforts, including varieties such as
Seri 82, Rayon 89, Altar 85, Pitic
62, Yecora 70, and Ciano 79. As
can be seen in Figure 1, potential
wheat yields (on-station trials)

and farmers' yields in the region
have progressed along similar
curves, with farm yields
gradually narrowing the
production gap. CIMMYT
economists note, however, that
since the mid-1980s the rate of
wheat productivity growth at the
farm level has slowed. At first
glance it may appear that farmers
may have peaked within the
current parameters, but a more
detailed look (Figure 2) broadly
hints at a more complex story. The
top 20% of farmers have neared
optimally profitable production
levels. CIMMYT analyses indicate
that additional incremental
expenditures of time and money
by farmers in this group probably
are not merited based on the
marginal gains that can be
obtained. To increase production

Yield (t/ha)




1951 56 61 66 71 76 81 86 91 96

Figure 1. Wheat yields in the Yaqui Valley, Mexico, 1988-96.

Potential Top Middle Bottom
20% 60% 20%
Figure 2. Wheat yields in the Yaqui
Valley, Mexico, 1988-96.

significantly, this group will
require a dramatic shift in the
yield frontier.

The story (and hence the strategy
for producing improved yields)
for other Yaqui Valley farmers,
particularly those producing in
the bottom 20%, is somewhat
different. Surveys reveal that
input levels for groups cited in
Figure 2 are essentially the same.
The critical difference in
productivity (which accounts for
a 2 t/ha differential between the
top and bottom groups)
apparently rests on management
and information variables. This
strongly suggests that substantial
yield gains could be obtained by
this group if farming and
management systems developed
by CIMMYT and INIFAP for
improved nitrogen use efficiency,
and application timing and
incorporation, were more widely
adopted. Such adoption, in turn,
CIMMYT economists say, rests on
factors related to human capital,

e.g., education and farming
experience. Although farmers in
the bottom 20% have the highest
potential for gains from adoption
of knowledge intensive
technologies, farmers in the
middle 60% could also boost
yields significantly through better
and more informed use of
existing technologies.

Expanding the yield frontier,
however, according to historical
trends, would increase yields for
all groups. CIMMYT's effort to
shift the yield frontier is being
pursued through three distinct
but inter-related strategies:

* Changes in wheat plant
architecture to produce a larger
head size with a higher number of
grains and no reduction in grain
size. CIMMYT breeders estimate
an 80% probability of success in
developing the new plant
architecture, which would
increase yields by 10-15 % above
Veery descendants.

* Hybrid wheat, originally viewed as
having great promise and then
falling out of favor, is being
reassessed in light of recent
improvements in hybridization
elements, advances in
biotechnology, and the emergence
of a new wheat plant type. It is
projected that increased grain
filling and heterosis together with
the new plant material could jointly
shift the yield frontier by as much
as 25-30%.

* Wide crossing, an important
technique for introducing stress
resistance in wheat, could also
lead to enhanced yields. CIMMYT
has produced an elite set of 95
synthetics (crosses between
durum wheat and goat grass, a
Triticum grass species) which have
been partially characterized for
morphological traits, yield
components, growth, and abiotic
and biotic stress. Major gains from
such synthetics would come from
using them as parent material in
the production of hybrid wheat.

This welcome recognition
comes at a time when the need to achieve a positive impact in
farmers' fields has never been more challenging. Many
circumstances-witnessed daily in our work-lend urgency to our
task: the instability of governments and economies, the vagaries of
increasingly unpredictable weather systems, the volatility of the legal
environment with respect to intellectual property rights, and the
extreme necessity of poor people pushed to the margins of survival.

Last year we presented an overview of the impacts of research by
CIMMYT and its partners. This year we provide ten detailed
examples of impact:

+ Synthetic hexaploid wheats

+ Role of disease resistant wheat cultivars

+ Research to help maize farmers face drought

+ Acid tolerant maize: promoting sustainable farming on acid savannas

+ Wheat in West Asia and North Africa

+ The Regional Maize Program for Central America and the Caribbean

+ Cooperation to rescue seed of Latin American maize landraces

+ Participatory plant breeding in Southern Mexico

+ Impacts of participatory research on tillage and crop establishment in

rice-wheat systems in the Indo-Gangetic Plains

+ Exploitable production potential, the research frontier, and the wheat

yield gap: spring bread wheat in Mexico's Yaqui Valley

Aside from showing the impact of our research, these studies have
several noteworthy features. They highlight the range of partnerships
needed for effective research: collaboration among institutions, across
disciplines, and within different kinds of regional and local
initiatives. They provide examples of research impact at the farm
level and across agroecological zones. They reveal proactive efforts to
forecast the sources of impact in farmers' fields. Finally, they
demonstrate that many researchers and funding agencies remain
convinced that the lives of poor people can-and should-be
changed for the better, and that agricultural research can play a major
role in achieving this objective.

CIMMYT's Core Donors (1998)

The following is a list of CIMMYT's core donors, those who
contribute to either our core unrestricted budget, or who provide
core-restricted funds. These same donors also often provide
special project funds, as well.

European Union
Ford Foundation
Nippon Fundation
Republic of South Africa
Sasakawa Africa Association
United Kingdom
United States Agency for International Development
World Bank

Sustainable Maize and
Wheat Systems for
the Poor

International Maize and Wheat Improvement Center
Centro Internacional de Mejoramiento de Maiz y Trigo
Lisboa 27, Apartado Postal 6-641, 06600 Mexico, D.F., Mexico

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