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Contents

Foreword: Going Where the Maize Grows
Shivaji P an dey .................. ....................................................................... ................................................... iii

Stress-tolerant Maize for Farmers in Sub-Saharan Africa
M arianne BM nziger and Alpha O D iallo................................................... ................................................. 1

Research on Tropical Highland Maize
D avid B eck ...................................................................... .... ........................................................................ 9

Increasing the Productivity and Sustainability of Maize-Based Cropping
Systems in the Hills of Nepal
Joel K. Ransom and Neeranjan Rajbhandari............................................................................................. 18

Quality Protein Maize: Improved Nutrition and Livelihoods for the Poor
Hugo Cdrdova .................................................................. ..... 27

Storage Pest Resistance in Maize
D avid B ergvinson ................. ......................................................................................................................... 32

The CIMMYT Maize Program in 2000
Shivaji P an dey .................................................................................................................. ................... ...... 40

M a ize P ro g ra m S ta ff .............................................................................................................................. 45

Maize Program Publications ........................................ 46

ii
Maize Research Highlights 1999 2000

Foreword: Going Where the Maize Grows

Few businesses or consumer products are central to the nutrition,
livelihoods, and even survival of people in settings as diverse as the
Brazilian prairies, the backlands of Bihar, India, northern Mexican deserts
at sea level, remote Andean highlands at well above 3,000 meters,
landlocked Zimbabwe, or far-flung islands in the Philippines. Maize and
maize farming and consumption, however, are common denominators in
the lives of all those people and many others in developing countries. The
dependence of these farmers and consumers on maize constitutes the
reason for the existence of the CIMMYT Maize Program.

Maize is produced on some 100 million hectares in the developing world.
In large parts of Africa and Latin America, inhabitants often consume
from 0.5 to 1.0 kg of maize each day, obtaining therein the bulk of their
carbohydrates and, occasionally, a significant portion of their protein.
Demand for the crop in Asia, especially as a component in animal feeds, is
rising much faster than the demand for rice or wheat. Either as a high
input, high-yielding commercial crop or, more often, as the anchor in
complex, small-scale, low-yielding, rainfed cropping systems operated by
subsistence farmers and their families, growing maize is a major economic
activity in developing countries.

To help the millions of maize farmers and consumers in the developing
world, the CIMMYT Maize Program goes where the maize is grown.
Working out of eight locations in maize-producing regions and four
research stations in CIMMYT's host country, Mexico, Program researchers
support and catalyze the efforts of many thousands of partners from
national maize research programs, private companies, non-government
organizations, and farmer associations worldwide.

During 1999-2000, the CIMMYT Maize Program and its partners in
maizer research systems of developing countries worldwide recorded
significant accomplishments in benefit of maize farmers and consumers.
Among these were the development, testing, and successful promotion
stress-tolerant maize for sub-Saharan Africa and the release of new,
high-yielding quality protein maize (QPM) hybrids and varieties in
morethan a dozen countries in Africa, Asia, and Latin America.
Two CIMMYT researchers received the 2000 World Food Prize for their
leading role during the 1970-80s in the development of QPM. There was a
sizeable expansion in the use of CIMMYT highland maize germplasm by

SCali, Colombia; Addis Ababa, Ethiopia; Guatemala City, Guatemala; Delhi, India; Nairobi, Kenya; Kathmandu, Nepal; Lima, Peru; and Harare,
Zimbabwe.

Mae R Highi
Maize Research Highlights 19992000

seed companies and farmer associations in Mexico, where nearly half
the world's 6.3 million hectares of highland maize is grown. Maize
Program researchers also homed in on the biochemical bases for
resistance in maize to post-harvest storage pests. This should facilitate
breeding for this important trait. In Nepal, the Program advanced
recently-begun work to develop and deploy productivity-enhancing,
resource-conserving technologies for maize farmers in fragile hill
environments. Finally, there have been important shifts in Program
strategies and approaches in recent years, to better address maize
farmers' concerns in a rapidly evolving environment including, among
other things, increased emphases on private enterprise and open
markets.

The first number in a yearly series designed to keep interested readers
abreast of progress in the Maize Program's global research agenda,
Maize Research Highlights 1999-2000 provides details and supporting
data on the work outlined above, along with contact information for
Program researchers and a list of Program publications for the period
covered. Given the breadth of Program activities and their long-term
nature (meaning advances seldom come in yearly quanta), the
Highlights will truly be that-a selection of noteworthy topics that
vary from year to year. This edition was compiled and edited by
CIMMYT science writer Mike Listman. We hope you find the series
interesting and useful, and welcome your comments or other
contributions to improve it and to support the research it describes.

General information about the Maize Program or how to request
seedor publications is available on CIMMYT's internet page (at
www.cimmyt.org). Please feel free as well to contact me or any of
their researchers in the Program on these points.

Shivaji Pandey
Director, the Maize Program
CIMMYT
November 2001

iv
Maize Research Highlights 19992000

Stress-tolerant Maize for Farmers in

Sub-Saharan Africa

Marianne Banziger and Alpha O. Diallo**

Introduction

Population in sub-Saharan Africa is rising 3% per year,
but food production is increasing by only 2%. This net
decline in the food supply is being partly met through
imports and food aid. However, in many cases, the
populace is simply eating less: approximately 100
million people in sub-Saharan Africa are malnourished,
30 million of them children under 5 years of age.

Maize is the region's principal cereal crop. Farmers
harvest some 25 million ha of maize each year,
producing about 35 million tons of grain. This accounts
for 40% of the region's cereal production. Fully nine
tenths of the grain goes directly for human
consumption. Of the 23 countries in the world with the
highest per capital consumption of maize as food, 16 are
in sub-Saharan Africa. Maize provides 50% of the
calories in diets in southern Africa, 30% in eastern
Africa, and about 15% in West and Central Africa.

Despite its importance as a food crop, most maize in
sub-Saharan Africa is grown on small plots as part of
complex, low-input systems. Yields average 1.4 t/ha,
more than 1.0 t/ha below the average for all
developing countries. Farmers' low use of inputs stems
partly from a lack of cash (for example, 8 out of 10 rural
Malawians have an annual cash income of less than
US$15) and partly from the significant risks of crop
production. In a given season, crops can be damaged or
ruined by one or several important constraints:

SDrought. Insufficient or poorly distributed rainfall
reduces maize output across the region. Severe
droughts periodically destroy entire crops over large
expanses. Less than 7% of agricultural area in sub
Saharan Africa is irrigated.

* Nitrogen depleted soils. Nutrient depletion and soil
fertility decline are widespread in smallholder
farming systems, as many farmers cannot afford or do
not have access to organic and inorganic fertilizers.
* The parasitic weed, Striga spp., reduces maize yields
particularly in eastern and western Africa. Increasing
soil fertility is the best measure against this pest, but
often out-of-reach to resource-poor farmers.
* Maize stem borers. These field pests are particularly
damaging to plants weakened by one or several of the
preceding constraints.

Stress Tolerant Maize Developed under
Farmers' Conditions

To increase food security and alleviate poverty among
African farm families, in the mid-to-late-1990s CIMMYT
and its partners launched two major projects aimed at
making maize-based cropping systems in the region
more productive and, especially, more efficient in the
use of scarce water resources and soil nutrients:

* The "Southern African Drought and Low Soil Fertility
Project" (SADLF) features work by CIMMYT
researchers and partners2 in southern Africa, with
funding from the Swiss Agency for Development and
Cooperation (SDC) and the Rockefeller Foundation.
Its central goal is to develop and deploy maize that
yields more and has more stable yields under

* Maize physiologist; ** maize breeder.
2 Work is supervised by the Southern African Center for Cooperation in
Agricultural and Natural Resources Research and Training (SACCAR)
of the Southern African Development Community (SADC), and major
partners include the national maize research systems of Angola,
Botswana, Lesotho, Malawi, Mozambique, South Africa, Swaziland,
Tanzania, Zambia, and Zimbabwe; leading non-government
organizations involved in rural development in the region; and private
seed companies.

1
Maize Research Highlights 1999 2000

conditions typical of those faced by resource-poor
farmers, without depleting natural resources. It began
in 1996 and is now in its secondphase.
* In early 1998 CIMMYT, the International Institute for
Tropical Agriculture (IITA), and national agricultural
research systems3 began joint work under the project
"Developing and Disseminating Stress-Tolerant
Maize for Food Security in East, West and Central
Africa" (popularly known as the Africa Maize Stress
project, or AMS). Objectives are to 1) develop maize
varieties, lines, synthetics, and hybrids with
improved yield stability when grown under stress
from drought, insufficient soil nitrogen, Striga, and
stem borers; 2) promote the dissemination of stress
tolerant varieties and hybrids to African farmers; and
3) strengthen the capacity of our partners to achieve
the above. Funding through 2000 was provided by
the UNDP Regional Bureau of Africa, the UNDP
Sustainable Energy and Environment Division
(SEED), the Swedish International Development
Cooperation Agency (SiDA), and the International
Fund for Agricultural Development (IFAD).

Both efforts attempt to bring farmers' conditions and
concerns onto experiment stations, essentially
developing new varieties and hybrids simultaneously
under both stressed and favorable conditions, and
advancing only genotypes that perform well in both
settings. This approach contrasts with the focus of
conventional public and private sector breeding
strategies on increasing yields primarily under
optimal,well-managed conditions and assuming that
such increases will carry over into less productive
environments. The stress breeding methodology was
developed over more than a decade of research at
CIMMYT headquarters, with funding largely from
UNDP. Both projects are also developing capabilities
forl) innovative, lar ge-scale, on-farm testing and
demonstration of promising varieties, and
2) establishing sustainable systems for pr oducing and
selling quality seed of stress tolerant maize. Finally,
staff of both projects interact continuously and
substantively, exchanging germplasm and information
to develop useful products for African maize farmers.

Southern Africa

To introduce the stress breeding approach to
southernAfrica, SADLF staf f first had to demonstrate
its usefulness to researchers strongly wedded to
oldpractices of maintaining "well-manicur ed"
experiment fields. This was accomplished early on
through head-to-head comparisons under managed
stress conditionsbetween leading cultivars fr om the
region and CIMMYT experimental, stress tolerant
genotypes. Though not necessarily adapted to the
region, the stress-tolerant materials clearly outyielded
the local favorites when exposed to severe drought
and low N stress, two common stresses in resource
poor farmers' fields.

The project next helped establish and maintain
regional drought and N stress screening sites (Table 1),
trained regional scientists, and characterized target
environments using geographic information systems
(GIS). A few specifics are described below.

GIS Characterization of Environments. To obtain
better information on the environments where maize
is grown, project staff worked with CIMMYT's GIS
and modeling lab and the Blackland Research and
Extension Center of the Texas A&M University
System,4 to create the Africa Maize Research Atlas
(Hodson et al. 1999). This CD-ROM-based tool makes
a range of GIS data readily available for manipulation,
analysis, and output as tables, figures, and maps, to

Table 1. SADLF drought and N stress screening sites.

Low Nitrogen Drought
Angola Mazozo Mazozo
Botswana Sebele Maun and Ethsa
Malawi Chitedze Chitala
Mozambique Umbeluzzi Sussundenga
South Africa Viljenskroen
Tanzania Arusha Arusha
Zambia Golden Valley, Kabwe Nanga
Zimbabwe Harare Save Valley, Chiredzi

3 Participating countries are Benin, Burkina Faso, Burundi, Cameroon, Congo, Cote d'Ivoire, Ethiopia, Ghana, Guinea, Kenya, Madagascar, Mali, Nigeria,
Rwanda, Senegal, Sudan, Tanzania, Tchad, Togo, and Uganda. The AMS works in partnership with the West and Central Africa Collaborative Maize
Network (WECAMAN) operating under the sub-regional organization, the Conference des Responsables de Recherche Agronomique Africains (CORAF),
and the East and Central Africa Maize and Wheat Network (ECAMAW) of the Association for Strengthening Agricultural Research in East and Central
Africa (ASARECA). F. 11 in the case of SADLF, there are close links with leading non-government organizations and private seed companies.
SThe Blackland research team has since left Texas A&M to work with the company "Mud Springs Geographers."

2
Maize Research Highlights 19992000

Stress-tolerant Maize for Farmers in Sub-Saharan Africa

name a few of its salient features. The Atlas indeed
allowed SADLF to refine the definitions of maize
environments in the region. But the tool, plus training
in its use, was also provided to more than 200 African
researchers, and users now include personnel from
other CGIAR centers (ICRISAT, ICRAF, and ILRI),
private seed companies, and NGOs. Thus, the Atlas'
impacts in research priority setting, regional
collaboration, and effective targeting of new
technologies go far beyond SADLF.

Regional Trials. To highlight differences between
varietal performance under optimal management and
farmers' conditions, a regional testing network was
established among countries with stress screening
sites. This network was consolidated with other
regional testing efforts. Maize cultivars at the release
and pre-release stages from public and private seed
producing entities are now routinely evaluated for
tolerance to drought and N stress, as well as response
under favorable conditions and resistance to several
important diseases (all traits that affect a cultivar's
performance under smallholder farmer conditions).
Characterization for tolerance to acid soils and storage
pests was also begun in 1999.

Interest in the trials has grown rapidly, and the
number of trials has increased from 120 in 1996 to 395
in 2000. The trial network encompasses more than 50
collaborators and 30 institutions, and more than 150
elite, open pollinated varieties and hybrids from both
private and public organizations are evaluated each
year. Trial results are distributed to more than 300
institutions and individuals from the maize seed
sector, and several national programs and non
governmental organizations (NGO) have begun using
results to select entries for national maize variety trials
and seed dissemination. Partial cost-recovery has been
initiated through paid entries from the private seed
sector.

Germplasm Products. Several cultivars already
available in the region were identified as significantly
higher yielding under drought and/or N stress, a
characteristic not previously used to promote those
cultivars. In addition, the project developed
experimental maize genotypes that yielded 50% or
more grain than popular check varieties or hybrids
under levels of drought and N stress capable of

reducing average yields to about 1-2 t/ha. One
open-pollinated variety developed by the project
ZM521-has attracted particular attention. In 37 trials
conducted throughout eastern and southern Africa,
ZM521 yielded on average 34% more than current
releases and showed impressive yield stability. In one
set of trials where yields averaged only 1-2 t/ha (typical
for smallholder farmers), ZM521 yielded 2.2 t/ha,
surpassing local check cultivars by 50%. ZM521 is
planted in on-farm trials across the SADC region,
farmers and seed producers are greatly interested in it,
and commercial seed production has begun.

In summary, SADLF has produced release-ready
cultivars with 35-50% higher and much more stable
yields for smallholder farmer conditions. The
genotypes use water and nutrients more efficiently to
produce grain, thus maintaining a relatively high
harvest index (HI) under conditions that normally
reduce HI to less than 0.2-0.3. In this sense, stress
tolerant cultivars give smallholder farmers incentives
for the first time to use improved management
practices and to diversify crop production.

Moving SADLF On-farm. Having established
infrastructure and partnerships and developed
experimental, stress tolerant genotypes, the project then
faced the challenge of systematically and cost
effectively verifying the performance and acceptance of
new maize cultivars under farmers' conditions. To this
end, SADLF adapted an approach pioneered for
agronomy research by an ICRISAT researcher. Dubbed
"Mother-Baby Trials," it involves sets of experiments
grown in and by farming communities. For each
researcher-managed "mother" trial, there are as many
as 6 to 12 corresponding "baby" trials within bicycling
or walking distance and managed entirely by farmers.
The mother trial evaluates a set of promising maize
cultivars under recommended and farmer
representative management conditions, thus
demonstrating both differences between varieties and
the effect of improved management practices. The
mother trial is located in the center of a farming
community, often at a secondary school, in the field of a
progressive farmer, or at a research station. It is
managed by a local counterpart, the agricultural
teacher, an extension officer or an NGO staff. Baby trials
contain a subset of the cultivars in the mother trial (no
more than four) and are planted and managed

3
Maize Research Highlights 19992000

exclusively by the farmers that host them. Because
farmers want to use the information from the trials for
purchasing seed of a good cultivar in the following
year, only half of the entries are experimental; the
remainder are recent releases already available on the
market. Thus, adoption of newly released germplasm
is taking place while research is conducted and
decisions are made on future releases.

Performance data and farmers' opinions flow back to
researchers and seed companies, increasing the chance
that companies will provide the kind of seed that
farmers really want. Through deliberate collaboration
with a range of partners (NGOs, research stations,
extension agencies, schools, farmers) and by
providing valued information to seed companies, the
system is expected to become self sustainable after an
initial start-up phase.

In 2000, 37 mother trials and more than 280 baby
trialswer e piloted throughout Zimbabwe (Fig. 1).
Collaborating partners included private seed
companies; NGOs such as CARE International,
SALRED (Southern African Unit for Local Resource
Development), and ITDG (International Technology
Development Group); community development
associations, such as the Horseshoe Farmer
Association in northern Zimbabwe, in which
commercial farmers link with smallholders to

Figure 1. Mother-baby trial sites in Zimbabwe, 2000.

improveagricultur e; the national extension service
(AGRITEX); 15 secondary schools; and several
national research stations. The trials involved not only
individual farmers but entire communities through
visits by neighbors, field days, oreven interactions
between school children (who managed some mother
trials) and their parents. In summary, the results have
been useful for all and enthusiasm ishigh.

SADLF also collaborates with the CIMMYT
coordinated "Soil Fertility Management and Policy
Network for Maize-based Farming Systems in
Southern Africa" (Soil Fert Net), to test and target
stress tolerant varieties. Funded by the Rockefeller
Foundation, Soil Fert Net is working to improve the
management of soil fertility resources in the maize
based smallholder farming systems of Malawi,
Zambia, and Zimbabwe through effective, targeted
research and extension, widespread partnerships, and
appropriate policy support.

East, West and Central Africa

There is no question that the challenges to maize
production in West, Central and East Africa are
significant. However, technologies are available and in
the pipeline that can significantly contribute to

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Maize Research Highlights 19992000

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Stress-tolerant Maize for Farmers in Sub-Saharan Africa

addressing these challenges. CIMMYT and IITA h
been collaborating with the national systems in th
region for more than 20 years to develop higher
yielding maize varieties adapted to the conditions
Africa's resource-poor farmers. Phase I of AMS
entailed an intensive effort to incorporate stress
tolerance into these varieties. From the beginning,
project was conceived of as a long-term effort,
requiring 10-15 years to show full results in farme
fields. The main focus in Phase I was on establish
the research infrastructure required for stress tolei
breeding. An expert review of Phase I conducted i
February 2001, led by Drs. Duncan Spencer,
Nyanguila Muleba and Fred Wangati, rated the p
as one of the top three projects currently funded b
UNDP worldwide. Among the most significant
accomplishments of the AMS project in Phase I ar
following:

Development of Research Infrastructure. The An
has successfully established field experimental
facilities that represent the major agro-ecological
domains for maize production as delineated in th

Figure 2. Grain yield and days to anthesis of the best
stress tolerant population (Best ent.) compared to a
commercial hybrid (DH 1) and the regionally popular
Katumani, across seven environments representing
optimal management (OPT), random drought and low
nitrogen (RDR), and managed drought and low soil
nitrogen (MDR), 1999A.

OPT RDR MDR

Best ent = Katumani `. CI. I

- AD Best ent

..... AD Katumani

- AD DH1

ave
e

of

this

rs'
ng
rance
in

project
y

e the

CIMMYT Maize Research Atlas. The screening and
testing sites have been selected to coincide with the
major maize stress factors of interest to the project and
over 200 on-farm trial sites were selected around
screening and testing sites in 9 countries. The AMS has
contributed significantly to infrastructure and
operations at these locations. A total of 19 sites to
screen for AMS project stresses (six in West/Central
and 13 in East Africa) and 126 testing sites (66 in
West/Central Africa and 60 in East Africa) are now
fully functional and under the direction of national
systems, enabling African maize researchers to
conduct stress breeding research for the first time.
What is more, researchers received training in new
breeding methodologies and all screening sites are
fully computerized, so that the efficiency of research
has been significantly increased.

Increased Availability of Stress-tolerant Maize
AS Germplasm. Although IITA and CIMMYT have been
developing stress tolerant maize varieties for many
years, the lack of screening and testing sites in the
e region prevented the incorporation of these materials
into varietal pools evaluated and released by African
countries. Under Phase I, more than 5,000 maize lines
new were systematically evaluated by project collaborators,
and a number of materials with resistance to one or
OPV,
more key stresses have been found superior in yield
soil towidely gr own varieties. Among these promising
soil
new materials are early and extra-early varieties that
farmers prefer to Katumani, the single most popular
"drought-avoiding" maize variety grown in East
Africa. The breeding and screening approach used
70 throughout the project guarantees that the new
6 maizevarieties outperform curr ent commercial
counterparts (varieties or hybrids) under stress
50 conditions, while yielding at least as well under
favorable conditions (Fig. 2). Thus farmers benefit
4 from higher and more stable yields when
30 H conditionsar e difficult, with no yield penalty under
20 good conditions.

10 Building Teams. AMS participants are proudest of the
fact that, more than simply consolidating existing
0
maize networks, the project has succeeded in creating
high-quality research teams. Screening sites are being
shared by national scientists across their respective
regions. National systems are joining hands to lead
research on particular stresses, with germplasm tested

5
Maize Research Highlights 19992000

regionally and findings shared across national
boundaries. National breeding programs are becoming
more focused, with better planning and priority setting.
Collaboration between CIMMYT and IITA is steadily
increasing. Overall, the intangible but invaluable factors
of trust and collegiality-without which collaboration is
impossible-are clearly evident among the international
centers, collaborating national systems, and the many
researchers involved in the project across sub-Saharan
Africa.

In short, Phase I of the AMS project has established a
very solid foundation of physical infrastructure, research
accomplishments, and human relationships. AMS
participants work in multi-disciplinary teams, with
extensive interactions among researchers from CIMMYT
and IITA, national programs, extension workers, NGO
staff, and farmers. Through extensive training activities
under the project, CIMMYT and IITA have provided
African scientists with tools to develop, test, and
promote stress tolerant maize in their home countries.
Moreover, capabilities and tools acquired through the
AMS are being put to a range of non-project uses in the
region, thus contributing to the emergence of modern
agricultural research and development. This positions
subsequent efforts to achieve accelerated impact, as new
technologies (germplasm and complementary
agronomic practices) are perfected and begin moving
into farmers' fields.

Variety Improvement. CIMMYT-Mexico, CIMMYT
Zimbabwe (particularly SADLF), and the former
CIMMYT program in Cote d'Ivoire have been the
majorsour ces of stress tolerant maize used in the AMS
project. CIMMYT-Mexico and CIMMYT-Zimbabwe have
sufficient germplasm in the pipeline forthe AMS to
upgrade varietal development continuously by
broadening the genetic base of project germplasm. IITA
and the national research systems have also contributed
significantly to the range and diversity of germplasm
used. Thus, more than 5,000 materials-exotic source
populations, local materials, progenies, and various
crosses-have been screened and tested in the region.

Project participants have effectively utilized this
germplasm, as well as landraces and popular farmers
varieties, in new stress tolerance breeding populations
likely to produce good varieties for farmers.
Germplasm is regrouped according to maturity and
geographic adaptation. Selected genotypes are selfed,
intercrossed, topcrossed and/or backcrossed repeatedly,
as deemed necessary, to accumulate favorable genes
through either simple recurrent or reciprocal selections.
Genotypes are tested in network regional trials and on
farm trials (both researcher and farmer-managed). The
same genotypes are simultaneously screened under
stress and unstressed conditions in different ecologies.
This ensures selection of germplasm that is well
buffered against environmental stress, a prerequisite for
minimizing yield losses under farming conditions. Final
release for use by farmers depends on stress tolerance,
yield potential, and agronomic qualities. Products
include high yielding varieties with good agronomic
background, inbred lines for use in developing hybrids,
and full vigor cultivars.

Secondary traits (anthesis-silking interval, tassel size,
ears per plant, plant height, lodging resistance, stay
green or delayed leaf senescence, abcisic acid in leaves,
root capacitance, leaf toughness) identified by CIMMYT
and IITA as being associated with stress tolerance are
used to speed selection and breeding. Because drought
and low-N stress tolerances are quantitative traits under
the control of several genes, gene markers obtained so
far account for only 40 to 50% of total genetic variation.

Progress in mapping genes for Striga resistance may
soon allow use of marker-assisted selection. Resistance
to maize streak virus (MSV), an important disease
endemic to sub-Saharan Africa, is also under control of
quantitative genes, but these are clustered in a genome
region sufficiently large to act as a single super-gene.
Thus, DNA markers for MSV account for over 90% of
genetic variation, and project participants are beginning
work to use them in selection.

Evaluation for storage and grain quality characteristics
is performed only at the farm level, but grain quality
characteristics (color, flintiness, and others) are already
incorporated into breeding populations.

5 Funded by the Canadian International Development Agency (CIDA), the EACP was initiated in 1985 to increase maize and wheat production and
productivity in eastern Africa. Now in its fourth and final phase to end in 2002, the project is focused on enhancing the productivity, effectiveness, and
efficiency of crop and natural resource management research and technology dissemination for maize and wheat-based cropping systems in eastern Africa.

6
Maize Research Highlights 1999 2000

Stress-tolerant Maize for Farmers in Sub-Saharan Africa

Agronomy and Cultural Practices. In East Africa, on
farm and on-station agronomic trials have been
conducted mainly by national scientists and funded
from competitive grants through the AMS or the East
Africa Cereals Programme (EACP).6 Experiments
have focused on moisture stress management,
especially through use of tied ridges, and nutrient
management. Regional trials on strategies for
addressing low soil fertility have been conducted in
Ethiopia, Kenya, Tanzania and Uganda. Eleven
potential legumes were tested for adaptation,
establishment and seedling growth, growth rates and
biomass accumulation, ability to fix N, and resistance
to insects and diseases. Regional trials were also
conducted on integrated nutrient management
involving combined use of small amounts of high
quality organic material with inorganic N.

In West and Central Africa, on-farm trials involved
intercropping forage legumes with maize. Work often
follows the WECAMAN practice that on-farm
research teams comprise a breeder, an agronomist, and
a socio-economist, and include economic analysis of
the results.

From this considerable body of work, AMS
participants are now attempting to identify, test, and
promote "best bet" technologies adoptable by farmers
in the short-to-medium term. In addition, participants
will attempt to standardize experimental designs for
on-farm trials, to facilitate comparative analysis across
the region.

Farmer Participatory Approaches. Farmer
participatory research in AMS has been mainly
collaborative, with strong collegial elements.
Participatory rural appraisal (PRA) has been used to
elicit farmers' problems and understand their
constraints. Participatory breeding and on-farm and
mother-baby trials (a methodology acquired from
SADLF) are being used to develop and test new
technologies with farmers.

In eastern Kenya, PRAs were conducted in villages
around each of four screening sites. Usually, separate
group interviews were conducted for men and women
concerning their preferences and selection criteria for
maize varieties. An open-ended questionnaire and
scoring scheme were used. For participatory breeding

in Kenya, a set of farmers who participated in
PRAswer e invited to each of four research stations
toevaluate dif ferent varieties being tested at the
screening sites and mother-baby trials were
conducted(Fig. 3).

Farmers and scientists are making use of the results,
obtaining information on the suitability of new
cultivars for different agro-ecologies and their
acceptability to farmers, who are pleased with the
approach. Farmer participatory variety selection has
also been institutionalized in West and CentralAfrica.

Seed Production. AMS has directly funded seed
production and on-farm testing (often jointly with
SADLF) in Burundi, Chad, Ethiopia, Guinea, Kenya,
Senegal, and Tanzania. Project participants have
collaborated in and backstopped maize seed
production activities in national programs. Together,
these activities account for the production of more
than 300 tons of maize seed annually. However, as
should be expected given the short time that
development of new stress tolerant varieties has been
underway, no new AMS varieties have entered the
seed multiplication programs. The AMS is supporting
the development of community based seed systems
and small seed companies in many countries in the
region and will allocate increased resources to this
activity, as stress tolerant varieties and hybrids from
its programs become available.

Figure 3. Participatory breeding under the AMS in 2000:
farmer evaluation of 52 maize varieties one week before
harvest (black = positive; grey = negative; white = neutral).

Number of farmers

7
Maize Research Highlights 1999 2000

.............................. ............................. ............................ ....
..........................................................................................

Strengthening National Research Systems. Courses
and workshops have been organized on selection
methodologies and for increasing farmer
participation in breeding and on-farm testing.
Topics and participants are chosen by national
systems and approval by the WECAMAN and
ECAMAW steering committees. The training
provided, especially in computing to manage and
evaluate large germplasm collections, has helped
improve the capacity of regional scientists and
technicians. Training events have also allowed
researchers from different countries to establish
friendships and professional ties, thereby fostering
trust and the free exchange of information and
germplasm. Frequent and extended contacts among
researchers from the region and the CIMMYT and
IITA teams has provided the former with access to
high quality germplasm and methodologies, while
allowing the international scientists to identify
promising local technologies and genetic materials.

The project has facilitated expansion of WECAMAN
membership from 8 to 11 countries, with the
recruitment of the the maize research programs of
Guinea, Senegal and Chad, and increased the
network's eco-regional coverage from the Northern
Guinea Savannah to all maize ecologies in the sub
region. In East Africa, the project has provided
valuable continuity and opportunities for
interaction and joint planning under ECAMAW.
Finally, the AMS has helped strengthen linkages
between ECAMAW and WECAMAN, improving
the efficacy of maize research and development
activities region-wide and laying the groundwork
for eventual establishment of a pan-African
organization.

Project Administration. The AMS is administered
as a joint collaborative project between CIMMYT,
IITA, and national research systems, with
administrative duties and research direction shared
between CIMMYT and IITA. The AMS is perhaps

one of the best recent examples of fruitful collaboration
between two CGIAR centers, and directors of
participating national systems have confirmed their
satisfaction with project management and operations.
Collaboration with NGOs and extension services is
developing steadily.

The Future

Chief among priorities for 2002 and beyond is securing
sustainable funding for the AMS and SADLF Firm
support for the latter already exists in SDC and the
Rockefeller Foundation. Given the favorable reviews of
the AMS, several donor agencies have expressed
interest in providing support. Assuming support
continues, SADLF and the AMS will pursue the
following:

* Mother-baby trials will be extended to other
countries under both projects, and GIS-based site
comparison studies will allow the projects to apply
the approach more efficiently. The value of obtaining
routine feedback to researchers and seed producers
from the thousands of farmers participating is
inestimable.
* As progress is made in breeding and release of
higher yielding and better-adapted varieties, the
main constraints to increased maize production in
the region will be the lack of quality seed at
affordable costs and the need for improved crop
management practices. Both SADLF and the AMS
are working to foster the establishment of effective
community-based seed multiplication and marketing
systems, and improved crop and soil management
practices at the farm level.
* In breeding, efforts to use DNA markers will increase
and the projects will focus as well on developing
new, stress tolerant quality protein maize (QPM)6 for
sub-Saharan Africa as well as transferring the QPM
trait to elite breeding and released materials already
available for the region.

6 QPM grain contains nearly twice the levels of two essential amino-acids, lysine and tryptophan, as normal maize, as well as a more balanced
distribution of amino acids, ,i...i. II ........ its nutritive value. For more information, see "Quality Protein Maize: Improved Nutrition and
Livelihoods for the Poor," p.27.

8
Maize Research Highlights 1999 2000

Research on Tropical Highland Maize

David Beck*

Introduction

The CIMMYT highland maize subprogram develops
improved germplasm for the approximately 6.3
million ha of highland maize area in the developing
world (Table 1). Almost half of this area is in Mexico;
the remainder is in Central and South America, Africa,
and Asia. Hard grain types predominate in Mexico,
Asia and Africa. Floury and morocho7 grain types are
popular in South America (Table 2). White grain maize
is preferred in 80% of the world's highland areas. This
is because most highland maize is consumed directly
as food by farmers and their families, and white grain
is most suited for typical foods. Highland maize areas
in developing countries can be classed into three
broad, or "mega"-environments (Table 1).

Major abiotic constraints of highland maize include
cold temperatures, frost, hail, and drought. Principal
biotic constraints are Puccinia sorghi rust, Exserohilum
turcicum leaf blight, and Fusarium ear and stalk rots.
Insects usually are not a problem, although corn
earworm can cause significant damage particularly in
soft endosperm materials. The myriad of highland
environments and the resulting genotype by
environment (G x E) interactions, coupled with farmer
requirements for grain texture, color, and size present
significant challenges for breeding. At present in most
highland environments, there is widespread use
(nearly 90%) of local varieties.

The Mexican Highland Maize Farmer

A typical Mexican highland maize farmer lives in a
high valley or plateau some 2,000-2,800 meters above
sea level. He most likely farms ejido (communal) land,
and has about 2-5 ha. His maize is of the C6nico or
Chalqueno race type, characterized by purple and
pubescent stems, high numbers of basal tillers under
high soil fertilility conditions (few to none under
typical farmer conditions), a very low tassel branch
number (mainly C6nico), and ears with a high shelling
percentage as a result of small cobs and deep grains.

About 80% of the arable land on his farm is planted to
maize. Other crops grown are alfalfa, faba beans,
phaseolus beans, and perhaps some cool season
vegetables (broccoli, cabbage, carrots, etc.) and orchard
crops (apples, peaches, pears, plums, etc., and highland
avocado). He lives in a farming village, and travels to
his plots each day. He usually has horses, mules, or
burros which are used to transport him and his farming
equipment to his fields. Plowing is usually done by
tractor, but furrowing, planting, and cultivations are
still commonly done using animal traction.

His maize is normally grown as a rainfed crop. If soil
moisture permits, he normally plants deep (as deep as
25 cm) into residual moisture to get the maize crop

* CIMMYT maize breeder.
SMorocho grain is floury but has a hard outer cap.

Table 1. Highland maize mega-environments in developing countries.

Extension Mean
Highland (million ha); Altitude range growing season
mega- [% world (meters above temperatures
environment Location highland area] sea level) (oC)

Tropical 0-30 N and S 3.3 [54%] 2,000-3,600 12-17
Transition 0-30 N and S 2.3 [38%] 1,500-2,000 17-20
Temperate 30-42 N and S 0.5 [8%] 1,200-2,500 15-20

9
Maize Research Highlights 19992000

started before the advent of reliable rains in June.
Maize production here is mainly for home
consumption. Farmers plant an intermediate-late
white semi-dent type as the main crop, which has a
growth cycle of 6-9 months. At higher elevations, they
will also sow an early blue floury maize (6-7 months
to maturity) nearby, or an early yellow or mixed color
semi-dent maize in lower and dryer areas (5-6 months
to maturity). In some high cool areas, farmers may
plant a considerable amount of highland early white
floury (Cacahuacintle) maize for home use and for
marketing as fresh ears for sale or use in local dishes.

Maize fodder is an important commodity in many
areas. At physiological maturity or just after the first
frost, plants are cut at the base and tied into shucks.
The objective is to produce forage with the maximum
amount of tender leaves. Normally those who cut and
shuck maize wait about one month before untying the
shucks for harvesting of dried ears. All harvest is by
hand, but machine harvest is feasible for the hard
grained types.

Near major metropolitan zones, the dried husks have
a high market value for use as wrappings for tamales
(a maize food cooked and served in maize husks).
This work is very labor intensive. Another specialty
food made from highland maize is maize smut (a dish
known as cuitlacoche, caused by the fungus Ustilago
maydis). The fungus is considered a great delicacy and
commands a high market price near large
metropolitan areas. It is best if harvested when the
smut galls are young and tender.

Table 2. Types of highland maize grown in the Andean
zone, by grain texture.

Texture Bolivia Colombia Ecuador Peru Total
(000 ha)

White floury 45 10 10 67 132
Yellowfloury 55 40 29 124
White morocho 15 50 20 85
Yellow morocho 65 150 10 41 266
Others 20 40 20 14 94
Total 145 305 100 151 701
*(127 177 151 137 592)
% maize area 45 53 40 39 46

Source: Dr. Shivaji Pandey, CIMMYT, Cali, Colombia, April 1991.
* Data from Dr. Miguel Lopez-Pereira, CIMMYT Economics Program,
1990.

The Andean Highland Maize Farmer

A typical Andean highland maize farmer lives in a
high, narrow, inter-Andean Valley some 2,200-3,200
meters above sea level. He is most likely farming
private land, and has about 2 ha. He plants about
25% of his arable land to maize.

His maize is a floury or morocho type, characterized
by non-tillering plants with often purple and
pubescent stems, a high tassel branch number, and
ears with extremely large kernels. The ears have 8
kernel rows, on average. Farmers often plant a high
proportion of the maize land to floury maize for
harvest and sale at the roasting ear stage. Dried
floury grains are consumed as roasted, whole grains
and morocho grain is consumed as mote. Harvesting
and shelling are done by hand, since the very large
and soft floury grain may be severely damaged by
machine shelling.

Other crops include climbing beans intercropped
with maize, lupines, quinoa, potatoes, cool season
vegetables and orchard crops, and some wheat and/
or barley. Maize is grown as a rainfed crop, but deep
planting is not normally practiced. The planting
season is from September to December. Full season
varieties mature in 8-13 months.

CIMMYT Highland Maize Program

In the 1970s, the CIMMYT highland maize
subprogram developed and improved 14 broad
based gene pools (4 floury, 4 morocho, and 6
semident) for the tropical highlands. During 1977
1986, CIMMYT worked with researchers in Ecuador
to improve floury and morocho maizes. In the mid
1980s, the CIMMYT program shifted its attention to
the hard-endosperm types that account for over 90%
of the world's highland maize. This has remained its
focus to the present.

Most unimproved highland maize has weak roots
resulting in significant lodging, high numbers of
basal tillers, low harvest index, and susceptibility to
inbreeding. To make matters worse, genetic
variability for these traits is lacking, so there is

10
Maize Research Highlights 19992000

Research on Tropical Highland Maize

limited opportunity for improvement. To overcome
these drawbacks, CIMMYT breeders adopted the
strategy of assembling populations that included a
portion of temperate and subtropical germplasm, to
allow for more rapid improvement for agronomic traits.
Backcrossing and recurrent selection were used to
develop improved populations without losing

favorable cold tolerance genes. Populations developed
along with brief descriptions are listed in Table 3.
These improved populations have demonstrated
excellent performance (high yield, high harvest index,
limited tillering, good roots, and tolerance to major
foliar diseases) and are more tolerant to inbreeding,
making them more useful for developing hybrids.

Table 3. CIMMYT headquarters populations for highland tropical and highland temperate areas.

Population Code Description Primary target area

Highland early white
semident.

Highland earlyyellow
semident.

Highland late white
semident.

Highland late yellow
semident.

Highland earlywhite
floury.
Highland earlywhite
semident for very
cold zones.
Tepoztoctoc-13.

Tepoztoctoc-23.

Tepoztoctoc-33.

Tepoztoctoc-43.

Temperate highland
early white semident.

Temperate highland
early yellow semident.

Tropical highland
transition zone late
white semident.
Tropical highland
transition zone late
yellow semident.

Population 85

Population 86

Population 87

Population 88

Population 89

Population 900

Population 901

Population 920

Population 940

Population 960

Population 800

Population 845

Pool 9A

Pool9B

60% highland, 20% temperate,
20% subtropical/tropical
germplasm.
55% highland, 25% temperate,
20% subtropical/tropical
germplasm.
55% highland, 25% temperate,
20% subtropical/tropical
germplasm.
55% highland, 25% temperate,
20% subtropical/tropical
germplasm.
90% Cacahuacintle, 10%
Andean races.
Diverse highland germplasm

Selections from Pool 10A and
Pop 85.
Selections from Pool 11A,
Pop 86 and New Zealand hybrids.
Selections from Pool 12A and
Pop 87.
Selections from Pool 13A and
Pop 88.
Selections from Pops 85, 86, 87
and 88, New Zealand hybrids,
elite Corn Belt Dent and northern
European germplasm.
Selections from Pops 86 and 88,
New Zealand hybrids, elite Corn
Belt Dent and northern European
germplasm.
Selections from Kitale synthetics,
Ecuador 573, SR52, Tuxpeho de
Altura.
Same as Pool 9A plus Montaia
from Colombia and Guatemala
altiplano central selections.

Warmer highland
areas'.

Warmer highland
areas'.

Warmer highland
areas'.

Warmer highland
areas'.

Highland areas2.

Colder highland
areas2.

Mexican highland
areas'.
Mexican highland
areas'.
Mexican highland
areas'.
Mexican highland
areas'.
Himalayan
region4.

Himalayan
region4.

Eastern and
Southern Africa,
Nepal, Americas.
Americas, Himalayan
Region.

' Mean growing season temperatures of 15-17"C.
2 Mean growing season temperatures of 12.5-15"C.
3 For sowing up to 0.2 m deep.
4 Mean growing season temperatures of 15-20"C.

11
Maize Research Highlights 19992000

Recurrent selection in most of the populations listed
in Table 3 was completed in 1994. However,
significant resources have been invested in pedigree
breeding to develop inbred lines from these
populations. Additionally, heterotic populations
have been formed for the important, early maturing,
white semident group. Early generation inbred lines
derived largely from Population 85 were
recombined to form Population 902; lines from
Population 800 were used to form Population 903. A
smaller fraction of germplasm derived from Pool
10A, Population 901, and miscellaneous materials
from the breeding nursery were also included in the
recombinations. Populations 902 and 903 have been
handled in an S, x tester recurrent selection scheme.
Evaluations of drought and low N tolerance have
been incorporated into selection. To date, inter
population heterosis is approximately 10%.

Inbred lines released by the highland program
include seven early white and one early yellow
linein 1993, and eight early white lines in 1997.
Several lines have been used as parents in hybrids
developed by the Mexican national program or
seedcompanies. These pr oducts are the fruits of
extensive and on-going collaboration between the
CIMMYT highland maize subprogram and the
Mexican public and private sector.

Research in 1999

As of 1999 (and continuing to present), the highland
maize subprogram has increased its emphasis on the
following:

* The development of early maturing yellow-grained
heterotic populations.
* The development of elite QPM materials for the
highlands.
* Line recycling in all germplasm types.
* Selection for drought and low N tolerance in our
germplasm.
* In collaboration with the CIMMYT breeder in
Ethiopia, enhanced linkages in the development of
highland transition zone maize for Eastern Africa.
* Greater efforts in Mexico and all regions to help
accelerate the adoption of improved OPVs and
hybrids through training in seed production and
consultation.
* Research in seed production.

Collaborative Research. The subprogram continued
strong collaboration with Mexican institutions,
including joint trial evaluations, exchange of
germplasm, and visits and consulting, to name a few
activities. The principal collaborating institutes include
the National Institute of Forestry, Agriculture, and
Livestock Research (INIFAP), the Institute of
Agriculture, Livestock, Water, and Forestry Research

Table 4. Late yellow transition zone hybrids evaluated at two locations, Mexico, 1999.

Grain Days to Ear Ear
yield flower rot Moisture aspect
Pedigree (t/ha) (Female) (%) (%) (1-5)*

POOL9B C1 TSR 8P x POOL 9B CO R.L. 71 13.9 96 10 20.8 1.4
POOL 9B C1 TSR 8P x A.T.Z.T.R.L. BA90 5 12.0 97 2 18.7 1.6
POOL9B C1 TSR 12P x P.R.D.A.(2),S.M.L.,9A 11.0 91 14 17.1 1.4
CHECKS
POOL9B C1 5.4 94 24 21.2 2.6
ASPROS 910/ SB304 10.1 94 41 22.1 2.5
TROMBA 8.7 88 28 17.6 2.6
MEANS 8.6 94 20 20.2 2.3
C.V.% 16.0

* 1 = excellent, 5= poor.

12
Maize Research Highlights 19992000

Research on Tropical Highland Maize

and Training of the state of Mexico (ICAMEX), the
Autonomous University of Chapingo, the Colegio de
Postgraduados, the "Antonio Narro" Autonomous
Agrarian University (UAAAN), and the seed
companies ASPROS, ASGROW, and CERES. Most of
these organizations have now released hybrids whose
parents include one or more CIMMYT highland
inbred lines. In general, there has been a significant
increase in recent years in the use of CIMMYT
highland maize germplasm by our partners.

Training. CIMMYT highland staff traveled to
Zimbabwe, Kenya, Ethiopia, Guatemala, Trinidad,
Ecuador, and Bolivia in 1999 to visit highland maize
research and seed production efforts, help teach seed
production courses, and strengthen collaboration.

Germplasm Experimental Results. Late yellow
grained transition zone single-cross hybrids largely
based on lines developed from Pool 9B were tested
1999 (Table 4). The best hybrid, POOL 9B Cl TSR 8P
2P-1P-2P1P-3-B X POOL 9B CO R.L. 71-2P-1P-2P-2P
1P-1P, yielded 13.9 t/ha across locations (37% higher
than the best hybrid check and 157% above Pool 9B
Cl). Two others, POOL 9B Cl TSR 8P-2P-1P-2P-1-3-1 X
A.T.Z.T.R.L. BA90 5-3-3P1P-4P-2P-1-1 and POOL 9B
Cl TSR 12P-2P-1P-1P-2P-2-B X PR.D.A.(2),
S.M.L.,9A)-1-1-1-1P2P-2P, had excellent yields and
agronomic characteristics. Standability, plant and ear
aspect, and ear rot resistance were excellent in all
these hybrids.

Table 5. Three-way cross hybrids with CIMMYT, ICAMEX and CERES germplasm (BA-9914A).

Grain Male Plant Stalk
yield flowering height lodging Moisture
Pedigree (t/ha) (d) (cm) (%) (%)

(B16x B17)x CML349 8.6 85.3 236 0.0 34.5
(CML244 x CML349)x R-838C 8.5 84.3 222 0.0 28.4
(CML239 x CML242) x IML-11 8.4 75.5 206 2.1 31.0
(CML239 x CML242)x IML-19 8.1 79.8 193 0.0 27.5
CHECKS
CML244 x CML349 7.1 79.0 212 0.0 26.7
(CML244 x CML349) x IML-6 7.1 79.3 224 0.0 31.4

Table 6. Selected results from the CIMMYT Highland International Hybrid Trial (CHTH 1999) across 27 environments.

Grain Days to Plant Stalk
Entry yield silk height lodging Moisture
no. Code Pedigree (t/ha) (d) (cm) (%) (%)

1 CMS 959875 CML240 x IML-6 6.88 81 226 2.5 19.4
7 CMS 979075 P85C4 HCE 10-1-4-1-1 x CML349 6.59 77 237 1.8 18.9
16 CMS 939083 CML244 x CML349 6.58 78 236 1.2 19.8
15 CMT9790235 (BPVC.BA90163x P.800C5F37)xCML349 6.54 76 225 1.3 17.9
13 CMS 9790205 (P800C5F37 x BPVCBA90185) x CML349 6.47 76 236 2.5 18.0
2 CMS 9597293 BPVC.BA90 185-2-1-6-3-#x CML349 6.46 75 231 2.7 17.3
19 Local-check-1 6.96 87 242 4.6 20.3
20 Local-check-2 7.88 90 243 4.9 22.8
Means 6.15 77 224 2.6 18.0

13
Maize Research Highlights 19992000

To exploit heterosis in a broader range of white
grained highland germplasm, we crossed some of the
best CIMMYT maize lines (CMLs) and single-cross
hybrids with lines and single-cross hybrids from
ICAMEX, INIFAP-Aguascalientes, and CERES (Table
5). Over 200 crosses were produced at the CIMMYT
experiment station in Tlaltizapan in 1999. Two trials
of 110 entries each were formed and evaluated at El
Batan under both low N and non-stressed conditions.
Across two environments excellent yields were
observed in various crosses between CIMMYT and
INIFAP (B16, B17), CERES (R-838C), and ICAMEX
(IML-11, IML-19) germplasm (Table 5). Particularly
noteworthy was the three-way cross (CML239 x
CML242) x IML-19, which had high yields, short
stature, and low harvest moisture.

The CIMMYT Highland Trial Early/Intermediate
Maturity White (CHTH) in 1999 comprised 20
highland, early/intermediate maturing, white
grained, single and three-way cross hybrids.
Although the two local checks ranked first and
second for yield, they were significantly later in
flowering and higher in harvest moisture than most
of the CIMMYT hybrid entries (Table 6).

Table 7. The effects of different treatments on the
synchronization of flowering and on grain yield in six
highland maize genotypes, El Batan, 1999.

Grain Change in
yield male flowering
Pedigree (t/ha) (d)

Foliar application of N (1 or 2 dosis) 0.24 0.0
Foliar application of P (1 or 2 dosis) -0.34 0.0
Foliar application of gibberelic acid -0.51 0.2
Foliar application of micro-nutrients -2.13 1.5
Planting depth (5-7 cm) -0.06 1.8
Planting depth (5-10 cm) -0.33 3.6
Plant density (33,000-67,000) 0.4 2.8
Flaming -0.46 8.0
Cutting (4 leaf cut at ground level) -3.21 13.7
Cutting (4 leaf removing half plant) -0.53 3.5
Cutting (8 leaf removing half plant) -2.63 3.8

Seed Production Research. Given that many farmers
in developing countries do not replace their seed
annually with newly purchased commercial seed, but
rely instead on recycled seed saved from their own
harvest or obtained from other farmers, we wanted to
obtain estimates of yield reductions in different
highland hybrid types. Thus, we evaluated
inbreeding depression as a result of advancing
various early-maturing highland hybrids from F1 to
F2 and F3. Two single-crosses, three three-way crosses,
and two double-crosses were included in our study.
The trial was evaluated in El Batan under both low N
and non-stressed conditions. Trial mean yields
averaged 11.6 and 4.1 t/ha under non-stressed and
low N stressed conditions, respectively. Interestingly,
similar levels of inbreeding depression were
expressed under both conditions. Combined over the
two environments, the single-cross hybrids
demonstrated the highest inbreeding depression from
the F1 to F2 generations (35.5 %), followed by three
way crosses (31.2%), and double crosses (14.9 %).

A second study8 examined techniques for
synchronizing flowering in hybrid maize production.
The materials included three highland inbred lines
and three single-cross hybrids. Techniques used
either to delay or accelerate flowering included: 1)
foliar fertilizer applications (N, P, gibberellic acid,
micro-nutrients); 2) varying planting depth; 3)
varying planting density; 4) cutting; and 5) flaming.
Contrary to expectations, foliar fertilizer treatments
did not hasten flowering (Table 7). Deeper planting
delayed flowering 2-4 days, with minimal effects on
grain yield. No significant differences were observed
in flowering at the two plant densities tested. The
cutting treatments significantly delayed flowering
(from 3.5 to 14 days), but also stunted plants and
reduced yields. Interestingly, the flaming treatment
delayed flowering on average by 8 days with
minimal negative effects on plant development or
yield. With most of the techniques, the inbred lines
were more affected by the treatments than the
hybrids (data not shown).

8 Part of the MSc program of CIMMYT research assistant, Jose Luis
Torres.

14

Maize Research Highlights 19992000

Research on Tropical Highland Maize

Research in 2000

In addition to continued work on the research
described previously, the highland maize subprogram
expanded its efforts to include the following in 2000.

Crossing Highland, Transition Zone, and
Subtropical Maize. To enhance heterosis and increase
the yield stability of highland maize by broadening its
adaptation, the subprogram began crossing elite,
highland inbred lines with elite lines of transition zone
and subtropical adaptation. Preliminary results
suggest significant boosts in yield in numerous cross

combinations (Table 8). In crosses between transition
zone late white lines and highland late white lines
evaluated at four locations, the transition zone line
(TSRB(2)*9A)MZ2-3X-lP-lP-2P-1-lP-lP-1-lP-B-B in
combination with three different highland late lines
exceeded the yield of the best check hybrid by
13-16%. Most hybrids were shorter and earlier with
less ear rot than the best check hybrid. Similar results
were found in crosses between transition zone late
yellow and highland late yellow lines (Table 9.). In
this trial the top-yielding hybrids were 7-13%
superior to the best check and had vastly better
resistance to ear rot.

Table 8. Transition zone by highland white single cross hybrids evaluated in 4 locations, 2000.

Grain % over Plant Root Ear
yield best height lodging rot Moisture
Pedigree (t/ha) check (cm) (%) (%) (%)

(TSRB(2)*9A)MZ2-3X1 P-1P-2P-1-1P-1 P-1-1P-B-B X POB.87 C5 H.C.176-13-1-2-1-1-1-B-B 12.40 116 248 0.0 3.3 20.4
(TSRB(2)*9A)MZ2-3X1 P-1P-2P-1-1P-1 P-1-1P-B-B X B.T.V.C.H. BA92 1-B-1TL-1-1-3-B-B 12.02 113 239 1.1 4.1 23.3
(TSRB(2)*9A)MZ2-3X1 P-1P-2P-1-1P-1 P-1-1P-B-B X B.T.V.C.M. BA92 16-B-10TL-1-1-1-B-B 12.00 113 227 1.0 1.7 21.9
Best check (TROMBA) 10.65 244 3.8 7.2 23.5
Mean 10.60 243 0.8 4.0 22.6

Table 9. Hybrid single-crosses formed with yellow transition zone and late highland yellow lines, 2000.

Grain % over Plant Ear
yield best height rot Moisture
Pedigree (t/ha) check (cm) (%) (%)

POOL9B C1 TSR-12P-2P-1P-1P-2P-2-B-B-B x S.MORADO TARDIO TL93A 5-B-1TL-1-1-1-B-B 14.27 113 278 6.1 26.7
POOL9B C1 TSR-12P-2P-1P-1P-2P-2-B-B-B x POB.88CO HC 23-5-1-1-5-2-1-4-2-2-1-B-B 13.75 109 269 2.7 22.5
POOL9B C1 TSR-8P-2P-1P-2P-1-3-1-B-B x POB.88C5 HC 6-6-1-2-1-2-1-B 13.56 107 274 1.5 32.7
POOL9B C1 TSR-8P-2P-1P-2P-1-3-1-B-B x S.MORADO TARDIO TL93A5-B-1TL-1-1-1-B-B 13.48 107 270 2.5 32.5
Best checks
ASPROS-910 11.56 271 26.7 37.7
Niebla 11.62 273 19.0 29.5
Relampago 10.32 259 15.4 30.8
ASPROS-900 12.65 269 20.0 30.3
Mean 11.13 258 9.2 27.3

15
Maize Research Highlights 19992000

In a trial crossing lines from more divergent sources
(in this case late highland white x subtropical testers)
we found even higher levels of yield superiority over
the best commercial hybrid checks. Table 10 shows
results of single-cross hybrid combinations between
highland late white lines and subtropical intermediate
white testers. The best performing highland late line
(Pob.87C5HC95-24 1-1-2-1-B-B-B) in crosses with the
subtropical tester lines CML311 and CML384
exceeded the yield of the best check hybrid by 20 and
29%, respectively.

Added Germplasm Options for Partners. During
2000, the highland subprogram offered a greater range
of trials through the international testing system. For
the first time in our history, we supplied partners with
a highland early yellow hybrid trial plus four
advanced line trials. The line trials were grouped by
maturity and grain color and included highland early
white, highland early yellow, highland and transition
zone late white, and highland and transition zone late
yellow trials.

The Future

The subprogram is increasing research on yellow
and quality protein maize (QPM), among others, in
response to growing interest. This includes forming
yellow grain, early-maturing, highland heterotic
populations to complement the early-maturing,
white heterotic populations already formed. Line
recycling is receiving increased emphasis, including
work to convert highland CIMMYT maize lines
(CMLs) to QPM. Further studies on the physiology
of highland maize, along with better classifications
of highland environments through use of
geographic information systems and other
techniques, are needed to improve our
understanding of G x E and to develop more
efficient breeding strategies. With the placement of
a CIMMYT breeder in Ethiopia, links are being
strengthened to develop useful varieties for

Table 10. Hybrids based on highland late white by subtropical tester lines, 2000.

Grain Days to Plant Stalk Ear Plant Ear
yield % best male height lodging rot Moisture aspect aspect
Pedigree (t/ha) check flowering (cm) (%) (%) (%) (1-5) (1-5)*

B.T.V.C.M. BA92 16-B-10TL-1--11-B-B x CML-311 13.74 126 86.3 216 0.0 6.0 26.7 2.5 2.5
POB.87 C5 HC 95-24-1-1-2-1-B-B-B x CML-311 13.57 124 86.0 238 2.0 5.4 25.5 2.5 1.8
B.T.V.C.M. BA92 23-B-1TL-1-2-1-B-B x CML-311 13.52 124 86.0 241 0.0 5.4 32.2 2.4 1.8
POB.87 C5 HC 95-24-1-1-2-1-B-B-B x CML-384 13.48 123 91.3 241 2.0 2.4 25.1 2.4 2.0
Checks
CML-311 x CML-384 10.93 99.0 225 0.0 7.5 31.4 2.5 2.4
Tromba 10.72 90.3 229 0.0 4.4 22.9 2.4 2.6
Halcon 10.55 79.3 214 5.9 3.6 16.1 2.8 2.8
Mean 11.97 89.6 224 1.7 6.1 26.0 2.5 2.4

*1 =good; 5= poor.

16
Maize Research Highlights 19992000

Research on Tropical Highland Maize

highland transition zones in eastern Africa.
Greater efforts in seed production training and
consulting in Mexico and other regions will
help accelerate adoption of improved OPVs and
hybrids.

By Spring 2002 we plan to release
approximately l0lines adapted to either
highland or transition zones and having early
or late maturity and white or yellow grain type
(Table 11). We also will have available about 27
new synthetic varieties with similar
combinations of adaptation, maturity and grain
color (Table 12). The newly released highland
synthetics and inbred lines in hybrid
combinations will be further evaluated in a
series of international hybrid trials to be made
available in March, 2002 (Table 13).

Table 11. Highland program lines scheduled for
release in Spring, 2002.

Category # of Lines

Highland EarlyWhite 2

Highland Late White 3
Highland Late Yellow 3

Transition Zone Late White 2

Total 38

Table 12. Highland program synthetics
available in Spring, 2002.

Category # of Synthetics

Highland EarlyWhite 7
Highland EarlyYellow 4

Highland Late White 4
Highland Late Yellow 4

Transition Zone Late White 4
Transition Zone Late Yellow 4

Total 27

Table 13. CIMMYT International maize trials highland ecologies, 2002

Trial Grain
name Trial description Maturity color Entries

VARIETAL TRIALS

EVT17 EW Highland earlywhite variety trial Early White, Yellow 30

EVT17 IWY Highland interm.-late white &yellowvarietytrial Interm. White, Yellow 9

EVT17 TLWY Transition zone late white &yellow variety trial Late White, Yellow 9

HYBRID TRIALS

CHTH-HEW Highland earlywhite hybrid trial Early White 20
CHTH-HEY Highland early yellow hybrid trial Early Yellow 12

CHTH-HIW Highland interm.-late white hybrid trial Interm. White 15
CHTH-HIY Highland interm.-late yellow hybrid trial Interm. Yellow 12

CHTH-TZLW Transition zone late white hybrid trial Late White 15

17
Maize Research Highlights 19992000

Increasing the Productivity and Sustainability

of Maize-Based Cropping Systems

in the Hills of Nepal

Joel K. Ransom,' Neeranjan Rajbhandari **

Summary of Accomplishments

In 1999 CIMMYT began work with partners in Nepal
to develop and deploy productivity-enhancing,
resource-conserving maize technologies appropriate
for farmers' circumstances and the fragile hill
environments of Nepal. With funding from the Swiss
Agency for Development and Cooperation (SDC),
participants in this effort are identifying, testing, and
promoting promising technologies, especially
improved seed and agronomic practices, evaluating
adoption and constraints to adoption, and providing
training for national researchers, extension workers,
farmers, and other collaborators. The project focuses its
activities at four hill research stations, with seed
production and technical support being provided by
Nepal's National Maize Research Program, located
inthe lowlands.

The Hill Maize Research Project (HMRP) has now
completed its second year. Among its accomplishments
are a working version of the GIS-based Maize Almanac
for Nepal, developed under the leadership of the
CIMMYT Natural Resource Group's GIS and Modeling
Lab. The Almanac has been distributed widely and
demonstrated to maize scientists as well as to the
broader research and development community within
Nepal. The fieldwork of the project's baseline survey
was completed in May and the synthesis report of the
rapid rural assessments conducted in 1999 has been
published. Planning meetings that focused on soil
fertility and post harvest research aided in the
development of research programs for 2001. A range of

trials involving local and internationally developed
improved varieties was planted at each of the hill
research stations and/or associated outreach sites.
Breeders' seed of 13 released or pipeline genotypes
and foundation seed of 8 genotypes was produced.
Eight crop management experiments were conducted
at one or more locations. Community groups at 7
locations produced more than 13 tons of certified seed.
Three in-country training courses, "Using the Maize
Almanac," "Trainer's Training on Seed Production,"
and "Using Computers to Analyze Data," were held
during the year. Four scientists participated in training
courses outside Nepal. The following sections describe
in greater detail the importance of maize in Nepal and
advances and directions in the HMRP.

Maize in Nepal

Maize is the second most important staple food crop
after rice in Nepal. Furthermore, the importance of
maize in Nepal has increased substantially in the past
30 years with maize area and production nearly
doubling (Fig. 1). The crop is currently grown on some
800,000 ha with an average yield of 1.8 tons t/ha.
Maize is used primarily for human food, but is
increasingly important as an ingredient in animal
feeds, particularly where good roads and market
access exist. Maize stover is also an important source
of fodder for livestock in mixed animal-crop farming
systems where maize is grown.

* CIMMYT agronomist. ** CIMMYT adjunct scientist.

18
Maize Research Highlights 19992000

Increasing the Productivity and Sustainability of Maize-Based Cropping Systems in the Hills of Nepal

Maize is produced in three rather distinct agro
climatic zones within Nepal: the Terai and inner-Terai
(below 600 m), the mid-hills (600-1,800 m), and the
high-hills (above 1,800 m). The greatest area of
production (70%) is in the mid-hills, followed by the
Terai (22%) and the high-hills (8%). Although maize
area and production have grown substantially over
the past 30 years, maize yields have been more or less
static. According to estimates, during the next two
decades the overall demand for maize in Nepal will
grow by 6-8% per annum, largely as a result of the
increased demand for food in the hills as population
increases, and for livestock feed in accessible areas in
the Terai and inner-Terai as the demand for milk, meat
and meat products grows. Future production increases
must come from increased productivity in maize
based systems, as there is little opportunity for further
expansion of cultivated area, especially in the hills.
Nepal's policymakers and research directors have
given high priority to the development of agriculture
in the hills, and an increase in maize yield per unit
land area is an essential component of this.

2000

1800

1600
Yield
1400 (kg/ha)

1200

1000

800

600

400

200

Maize in the Mid-hills

Maize occupies about 80% of the cultivated land in the
mid-hills and is the major source of calories, an
important source of protein, and pivotal to family
survival and the well-being of some 10 million hill
dwellers. In the upper hills it is perhaps the third most
important crop, occupying about 30% of the cultivated
land. Maize is often grown in intercrop or relay with
millet, soybean, cowpea, and potato. From west to east
two agroecological zones can be identified in the hills,
each depending upon the monsoon rainfall pattern and
moisture regime:

The Western Dry Zone. This accounts for about 20% of
the maize in the mid-hills. Low rainfall and a late and
short duration monsoon characterize this environment.
The maize crop is established on quite reliable pre
monsoon showers. The growing season is short, prone
to drought and the usual practice is monocropping of
maize. Some winter rainfall allows for crop production
in the winter. Summer monocropped maize on rainfed
terraces, followed by wheat/or other winter crops,
iscommon.

a0 1------1---------1---------1--------I

N \ 0 0 0 0 0 0 0 0 0 0 0 0 o o c o P ^ o s, NZN

Figure 1. Maize area, production and yield over the period 1970-1999.

19
Maize Research Highlights 1999 2000

Area
(1000 ha)

Eastern and Central Wet Zone. This accounts for
about 80% of the maize in the mid-hills. The area is
relatively wet due to high rainfall with longer
duration of monsoon rainfall, but has relatively poorer
pre monsoon showers and almost no winter rainfall.
The major cropping pattern is a summer maize
relayed/intercropped system with millet or legumes.
In the lower elevations where irrigation is available
spring monocropped maize on irrigated terraces
followed by rice is common.

In the mid-hills monocropped early maturing maize is
sown in March, harvested in August and followed by
a crop of wheat or mustard. In the higher hills late
maturing maize is sown during April and often
relayed with millets or intercropped with legumes.
Harvest occurs in October, or later in the higher areas
because of the cooler temperatures. Maize-based
cropping systems are dual purpose: they provide both
grain and fodder, the latter as green thinnings
between emergence and flowering, or as mature plant
stover following harvest. Crop residues are thus fully
utilized either as fodder or compost, and none except
roots are returned to the soil. Though average maize
yields are low, they disguise a large variation in yield
among fields; some innovative hill farmers are
consistently producing maize yields as much as three
times the national average.

Mid-hill Productivity Constraints. The mid and
upper hills of Nepal are generally food deficit areas,
and additional food must be imported from the Terai
by road or carried by porter for several days.
Environmental deterioration is one result, as families
intensify cropping or expand farming into new and
fragile lands to meet their needs. Also common is
outmigration to already crowded urban areas, where
new arrivals usually add to the ranks of the destitute.
Because many men work off-farm, many of the day
to-day on-farm decisions are taken by women. These
include varietal and seed selection and the timing and
nature of management operations. Decisions related to
intercropping for households needs, for example, are
often taken by women. Goat herding also plays a
special role in the economic independence of women,
since goats are used as dowry and remain the
property of women after marriage. Thus, factors

which relate to the nutrition of the family and
household livestock (such as maize for fodder) may
directly affect women's status.

Yields fluctuate seasonally in the hills, but have begun
to decline. This reflects among other things the
expansion of maize into less suitable terrain, an
increased intensity of cropping and soil erosion, and
the low utilization of improved varieties. Traditional
fallows have all but disappeared. Reduced access of
cattle and people to forests and the increasing demand
for animal fodder have reduced the amount and
quality of compost, accelerating a decline in soil
organic matter and fertility and increasing the mining
of nutrients in even better endowed hill areas.

Although farmyard manure (FYM) is widely used on
maize, its availability has not kept pace with
requirements. One important ingredient of FYM is
leaves from the forest, and as the forest area has
declined or community projects have restricted access
to forest lands, so the volume of FYM has declined.
Deficiencies of N and to a lesser extent P and
micronutrients are increasingly common. Research is
greatly needed on resource management in rainfed
upland areas, especially in relation to terrace margin
management with alley crops such as forage shrubs
and trees, as it affects nutrient renewal (through N
fixation) and the livestock (feed) components of the
nutrient cycle.

Little chemical fertilizer has been utilized in the hills
in the past, and when used it was applied relatively
more to wheat and rice. A growing trend in areas with
some road access is the use of urea as a topdressing to
maize four to six weeks after emergence. Farmers
often apply and incorporate around 25 kg N/ha in
this manner, usually during weeding and just before
transplanting finger millet. There is further evidence
of growing labor and land shortages in the hills and
the drudgery associated with the transport of bulky
FYM (less than 2% N) to high hill terraces. Fertilizer is
subsidized (1 bag of urea costs around US$ 6.50 at
depots in the hills), knowledge about the short-term
benefits of fertilizer is becoming widespread, and its
usage seems here to stay, despite reservations in the
minds of many about its overall effects on soil quality.

20
Maize Research Highlights 19992000

Increasing the Productivity and Sustainability of Maize-Based Cropping Systems in the Hills of Nepal

Fertility levels also vary considerably within specific
fields. Experience suggests that a maize variety grown
on terraces, such as those encountered in Nepal, will
experience levels of available N that vary from near zero
on the inner margins of the terrace where compost may
not have been applied or where infertile subsoil has
been exposed, to 120 150 kg N/ha where manure piles
have been dumped prior to spreading, where urea has
been unevenly applied, or where soils are naturally
deeper and more fertile.

Although use of modern maize varieties and hybrids is
fairly widespread in the terai, adoption has been much
lower in the hills. To begin with, there is a shortage of
varieties suited to mid-hill conditions and requirements,
so farmers continue to grow the same maize varieties
year after year. Over time these become "contaminated
improved" varieties with possibly inferior production
characteristics. In addition, farmers sometimes prefer
local varieties over improved ones for reasons unrelated
to grain yield (e.g.; taste, early maturity, fodder yield,
quality husk cover, tolerance to field and storage pests,
early maturity). Storability is also a key factor: most
farmers keep maize as fully husked ears in outdoor
storage structures called Sulis or Thangros.

Aside from issues of adaptation, the lack of quality
seedr remains a major constraint to adoption in the hill
country; access to improved seed varies from generally
poor to non-existent. Problems in seed multiplication,
delivery and production at the community level are the
major bottlenecks and should be addressed through
community-based seed production programs. As well,
most farmers do not seem to think that processed,
improved seed is worth the investment, and it remains
challenge to demonstrate its worth under their
production conditions.

Efforts to increase the productivity of Nepal's maize
based systems must thus include the introduction of
both new adapted varieties and improved crop
management techniques to address the decline in soil
fertility and other natural resource constraints. Under
the present circumstances the scope seems limited to
increase the productivity of maize-based system in
uplands and in the more remote hill areas through
increased use of external inputs, with the possible
exception of improved seeds, though this may also be
changing as roads continue to be built.

The Hill Maize Research Project

Several maize-oriented projects have addressed
production issues in the past, but most focused on the
terai and inner terai regions. The HMRP began in
Nepal in January 1999 to increase the food security of
farm families in hill areas by raising the productivity
and sustainability of maize-based cropping systems.
To accomplish this, work focuses on the following:
* Developing and promoting 1) improved maize
varieties adapted to hill environments, and 2)
resource-conserving, productivity-enhancing crop
management practices for maize-based systems,
appropriate to farmers' circumstances and
compatible with existing cropping and livestock
systems.
* Reducing crop losses from drought, low fertility,
diseases and pests (including post-harvest insects
and ear rots) through focused breeding efforts and
integrated pest management approaches (mainly
host plant resistance).
* Strengthening the research capacity of the National
Maize Research Program (NMRP), the National
Agricultural Research Council (NARC) Agricultural
Research Stations, and allied institutions, with
special attention to linkages between technology
generation/verification and its delivery to farmers.

There is a wide range of partners or potential partners.
The NMRP has the national mandate for maize
research and improvement and operates its research
and source seed multiplication program through the
network of NARC research stations nationwide. Maize
research in the hills is concentrated at the Lumle,
Pakhribas, Kabre, Khumaltar, and Dailekh
Agricultural Research Stations. Each station also has a
command area of several districts where on-farm
research is conducted. The Department of Agriculture
has an agricultural development office in each district,
and there are some 55 districts in the hill areas of
Nepal. These in turn are supported by a network of
agricultural supply centers and sub-centers managed
by extension agents. The DOA also manages a
network of farms to produce seed and planting
materials in collaboration with NARC, and its
products are delivered to farmers through the
Agricultural Inputs Corporation (AIC), a parastatal

21
Maize Research Highlights 19992000

input-distribution organization that focuses mainly
on fertilizers. Finally, there are around 5,000 non
governmental organizations (NGOs) operating in
the hills of Nepal. Most have strong community
level connections, and while some are opposed to
the use of improved production technologies, there
are others who are searching for new ways of
increasing community wealth and sustainability.
Less than 20 of these are operating in across-zone
activities in agriculture; several are international
andothers have activities in many ar eas of Nepal
(examples include the Tuki Associations, Potato
Seed Producers Groups, KOSIPAN, CEAPRED,
CARE Int., Lutheran World Services, and World
Neighbours).

1999 Results: Laying the Groundwork. During 1999
the essential operational procedures and committees
were established and staff recruited. A beta version
of a maize almanac, which will allow NARC staff to
identify areas of common agro-ecology, was
developed and demonstrated to NARC scientists.
Rapid rural assessments were conducted
throughout the hills and priority research
constraints and important characteristics required
by farmers in new varieties were identified. A
questionnaire for a baseline survey was developed
and teams identified for its application. Twenty
seven germplasm evaluation trials containing exotic
material from CIMMYT Mexico and Zimbabwe
were successfully carried out at five research
stations and on adjacent farms. Several genotypes
were found to be well adapted with high yield
potential and were selected for further testing and
improvement.

Protocols for the development of community based
seed production were designed and plans advanced
for seed production at sites near the four main hill
research stations. A document summarizing
guidelines for streamlining the development,
testing, maintenance and seed production of maize
varieties was drafted.

The number of activities implemented by the project
increased significantly in 2000, as more scientists
became involved, and technical aspects received
fuller attention.

2000: Technical Activities in Full Swing. In the hills
of Nepal, maize is planted with pre-monsoon rains,
which arrived in early March this year. Most research
activities supported by the HMRP followed soon after.
Rainfall was above average (more than 6,000 mm of
rainfall was received at Lumle), which intensified
disease pressure and increased the incidence of
waterlogging in poorly drained fields. Maize
production and yield on a countrywide basis,
however, was greater in 2000 (1.48 million tons;
average 1.8 t/ha) than in 1999 (1.45 million tons;
average 1.77 t/ha). Maoist activities intensified within
Nepal and are particularly problematic to the project
at two key sites, Kabre and Dailekh. Basic grain prices
fell sharply because of the excellent rice crop
harvested in Nepal and in India. Although the price of
maize is not a significant concern for farmers who
consume all that they produce, the low price is a
significant disincentive to maize producers who
market some or all of their produce.

Improved Targeting: The Nepal Maize Almanac. A
working version of the GIS-based Maize Almanac for
Nepal was developed in 1999 and early 2000 under
the leadership of the GIS lab in CIMMYT-Mexico. The
Almanac, which includes both software and
databases, was released by CIMMYT in February. At
that time most of the scientists involved in HMRP
activities and other key research managers were
exposed to the potential uses of this tool and were
trained in its use. The Minister of Agriculture
enthusiastically participated in one of the training
sessions. Approximately 50 copies of the Almanac
were distributed on CDs. Additional data are being
sought to enhance the precision of the Almanac
outputs. As new data become available, they will be
incorporated into the existing databases and updated
CDs will be distributed. Among other things, the
Almanac was used to refine definitions of the major
maize growing ecologies of Nepal.

Socio-economic Surveys. A synthesis report from the
Rapid Rural Assessments (RRAs) conducted in 1999
was published. The RRAs were carried out at 46 sites,
which allowed for the first compilation of data on
socioeconomic, biological, and physical factors
affecting the production of maize across the entire
country. Data from these RRA clearly demonstrated

22
Maize Research Highlights 19992000

Increasing the Productivity and Sustainability of Maize-Based Cropping Systems in the Hills of Nepal

the need to shift research resources from the Terai to the
mid-hills, where most of the maize in the country is
grown and where it dominates the farming system.
They also helped to better define the environment in
western Nepal. Previously, western Nepal was thought
to be a dry zone requiring early maturing types. Closer
analysis has revealed that, although this region is dryer
than most areas of central and eastern Nepal, rainfall is
sufficient to allow the cultivation of high yielding full
season genotypes. The lack of adoption of adapted high
yielding varieties is partially explained by the fact that
farmer in western Nepal prefer maize varieties with a
floury grain-type suitable for making roti, a maize
bread that is the chief way inhabitants consume maize.
Farmers in this region also require access to early
genotypes, because most farmers do not have enough
stored maize to carry them to the end of the normal
growing season. Furthermore, reliable winter rainfall in
western Nepal allows for the cropping of wheat after
maize. These new insights have helped direct the
research towards developing genotypes that are more
productive and useful to farmers and towards
addressing the needs of the more intensive maize
wheat system. Little research had been directed toward
this cropping area in the past.

Socioeconomic data from these surveys showed that
little maize is actually sold to the formal market from
the hills; thus, maize farming generates little cash for
the household. Nevertheless, in addition to being the
primary source of food in most households, it is used
extensively to pay hired labor and for bartering in the
local markets. Interestingly, the RRAs revealed that the
use of urea is expanding, even in the more remote areas
of the country. This information has promoted
additional research on how to balance the nutrients
being supplied from both organic and inorganic
sources.

Starting from the maize ecologies defined using the
Almanac and data from the RRAs and baseline survey,
major biophysical and socioeconomic constraints to
maize production were identified. Applying a
methodology recently developed for use in establishing
global priorities for CIMMYT's maize program,
constraints were ranked according to efficiency,
poverty, subsistence and combined indices. The data
clearly indicate that the mid-hills of the Western,

Central and Eastern Development regions require the
greater emphasis and identified two constraints
white grubs and low plant populations-currently not
addressed under the HMRP, but for which activities
will be established in2001.

Monitoring Innovative Farmers. Staff at the four hill
research stations attempted to find and monitor
innovative farmers. This was the first time that NARC
scientists had undertaken this type of activity. This
year's work did not reveal any innovations that were
considered sufficiently promising to require further
evaluation in experiments. Initial findings that need
additional monitoring and clarification as to whether
they are indeed innovations and are practical for
wider implementation include:
* Early planting (10-15 days earlier than was
traditionally practiced) can produce higher yields.
* Applying manure in the winter rather than waiting
until the spring improves yield.
* Stacking maize stover and keeping it for 4 or 5
months improves its palatability.
* Use of Acornus calamus roots and Xanthoxylum
armatum and Artemisia vulgaris leaves helps reduce
weevil damage in stored grain.

Soil Fertility and Post-Harvest Management.
Working group meetings on soil fertility and post
harvest management were held to better understand
and document the research that has already been
carried out and to agree upon a strategy for
addressing these priorities within the project. As a
result of the soil fertility meeting, the HMRP now
focuses soil fertility research efforts on improving
thequality of or ganic materials applied by farmers,
developing more rigorous system-based fertilizer
recommendations, developing recommendations
thatwill allow for the incr eased inclusion of legumes
or high value crops in the system, and devising
methodologies that reduce losses of soil from erosion.
Furthermore, post-harvest research by HMRP
participants now concentrates on 1) developing new
storage structures or modifying existing ones to allow
for more rapid drying after harvest, 2) screening new
varieties more rigorously for resistance to post-harvest
insect infestations and damage, and 3) more carefully
evaluating the economics of biopesticides and

23
Maize Research Highlights 19992000

insecticides for the control of post-harvest insects.
Additionally more detailed information on
post-harvest losses and on grain use profiles has
beeninitiated.

Seed Production. Breeder's seed of the following
materials was produced at one or more of the Hill
research stations: Arun-1, Arun-2, BA 93, Ganesh 1,
Ganesh-2, Manakamana-1, Hill Pool Yellow, Hill Pool
White, Kakani Yellow, Madi White, Pool 21,
Population 22 and Rampur Composite. Foundation
seed of the following materials was also produced at
one of more of the hill stations: Arun 1, Arun-2,
Ganesh-1, Ganesh-2, Manakamana-1, Hill Pool Yellow,
Hill Pool White and Rampur Composite. The seed
multiplication program was better coordinated in 2000
than in 1999, so that the amount of land at the
experiment stations in the hills used for seed
production was reduced. Furthermore, earlier
plantings this year at Rampur will enable the HMRP
to supply most of the entries to be included in 2001
trials from local sources.

Genotypes being produced in 2000/2001 at Rampur
for use in the 2001 summer season include: Across
94502, Tlaltizapan 9542, Across 9433, Across 9244,
Harare 94502, Across 94501, Udipur 9433, Pop 45, Pop
42, Pop 44, Tlaltizapan 9544, Upahar, Narayani,
Manakamana-1, Manakamana-2, Hill Pool White, Hill
Pool Yellow, Across 9331, ZM621, SNSYN Fl (CGA
A/B-9), ZM601, DRACON SYN F1/DRBCO SYN Fl,
[P501-SRCO-F1/P502-SRCO] F1, ZM521, ZM421, SZ
SYNKIT II/SZSYNECU573, [AC 969-A-SR(Best FSO]
Fl-#, KIT/SNSYN[N3/(UX)]C1-F1l#, ECU/
SNSYN[SC/ETO]C1-F1l#, SUWAN-3, SUWAN-5.

Germplasm Testing. Eight observation trials were
grown in 2000, consisting of four experimental variety
or hybrid trials from CIMMYT-Mexico, two from
CIMMYT-Harare, inbred lines from CIMMYT
Thailand and F1 crosses generated at Rampur. From
these trials the following materials were selected and
will be evaluated in the Intermediate Yield Trial (IYT)
in 2001: Celaya-9733, Celaya-9745, Pantanagar-9745,
Bangalore-9745, Across-9745, Sids-9445, Tlaltizapan
9542, Across Mexico-97501, Across-97501 and
Across 94501.

The Intermediate Yield Trial was grown at four

locations in the hills. Based on the results of these trials,
the following genotypes were selected and will be
advanced for testing in the Coordinated Variety Trial
(CVT) in 2001: P501-SRCO-F1, DRACONSYNF1/DRBCO,
ZM601, ZM521, ZM421 and GRACE (EWI-2). The CVT
was grown in five locations, two by Lumle and one each
bythe other hill stations. The following genotypes
out-yielded the standard checks and were selected for
inclusion in the Farmer Field Trials (FFTs) in 2001:
ZM621, Hill Pool Yellow, Hill Pool White and
LATAC1F1/LATBC1F1. ZM621 was particularly high
yielding, producing 34% greater yield than the average
yield of the checks. It is interesting to note that the
material from CIMMYT-Zimbabwe is consistently doing
well in the mid-hills of Nepal and that three promising
genotypes that are being advanced in the testing system
were developed with input from the SDC-funded
projectat CIMMYT Zimbabwe.

Farmer field trials were grown in farmers' fields under
the supervision of staff from each of the four hill research
stations. Because of the large variation within these trials
and the small number of locations where they were
grown, there were no statistically significant differences
between varieties across sites. Nevertheless, based on
farmer feedback, Population-22 was the preferred entry
at most sites. Data on Population-22 will be compiled
and submitted to the varietal release committee in 2001,
and it may also be included in some limited on-farm
seed multiplication in 2001, if sufficient foundation seed
is available.

Improved Crop Management Practices. The
followingcr op management research trials were
conducted in 2000:
* Determining limiting nutrients (all hill research
stations).
* Synchronizing crop requirements for N with inputs
from organic and inorganic sources (all Hill research
stations).
* Optimizing the productivity of the maize/wheat
system in western Nepal (Dailekh).
* Optimizing maize soybean intercropping (Duerali,
Lumle's outreach site).
* Crop rotation and diversification to improve soil
fertility and productivity (Lumle).
* Optimizing maize and millet intercropping (varietal

24
Maize Research Highlights 19992000

Increasing the Productivity and Sustainability of Maize-Based Cropping Systems in the Hills of Nepal

combinations, direct seeding millet comparing maize
sole to the system) (Kabre).
* Evaluation of different legumes for intercropping with
maize-soybean, cowpea and beans (Pakhribas).
* Identifying a suitable scheme of planting legume
intercrops with maize-optimum ratio and density of
intercrop components (Pakhribas).

The major findings include the following:
* The soybean variety CN-60 grows well as an intercrop
with maize. The combination of maize intercropped
with CN-60 produces returns superior to other
intercrops and may be a viable option for extensive
areas that are currently growing maize-millet
combinations.
* Confirmation of the very important role that organic
inputs have on sustaining of the productivity of
maize-based systems in the hills of Nepal.
* Greater overall productivity is achieved with
intercropping; selecting intercrop varieties and
speciesthat ar e adapted to the heavy rains during
themonsoons is a key ar ea for further research.
* Improvement in the management of trials,
particularly those conducted on-farm, is needed at
most sites to generate reliable data and develop
effective recommendations. Much of the training in
2001 will focus on improving trial and data
management.

Improved technology dissemination. Farmer
fieldtrials wer e planted on-farm in outreach sites
associated with each Hill ARS. Diamond trials were
planted at Dailekh and Kabre to demonstrate the
effectof impr oved soil fertility and varieties on
yield.Inaddition, the "Limiting Nutrient" and
"Synchronizing N Requirement" trials described above
were planted on-farm, though the intent of these trials
was more towards gathering data to enableef fective
recommendations, rather than on thedemonstration
ofa new technology per se. The soybean-maize
intercropping research at Duerali, an outreach site of
Lumle, generated a great deal of interest within the
community where it was grown. Many farmers
requested seed of CN-60. This work will be expanded
tomor e sites in 2001.

Community Seed Production. The lack of of good
quality seed constrains the adoption of improved
genotypes in the hills of Nepal. Given the
inaccessibility of most villages in the hills,
conventional methods of supplying improved seeds
are ineffective. The project is, therefore, supporting the
production of seed at the community level. Seven
farmer groups under the supervision of the four hill
research stations successfully carried out community
based seed production. In total, 13.7 t of seed of three
varieties was produced. A total of 99 farmers were
involved in these seed production activities. In
addition to providing foundation seed of the varieties
to be multiplied, HMRP provided technical support to
farmers producing seed, with limited advice on issues
related to group formation and marketing. There are
concerns that at some sites the seed producers will not
be able to sell all that they produce. Some emphasis on
assisting producers in linking with others involved in
marketing seed should be provided next year. It is
recommended that the program be expanded into new
areas next year, but technical advice to groups that
produced seed in 1999 should be continued if
required. Given the poor market linkages between
villages in the hills, the project will strive to support a
large number of relatively small production
enterprises so that seed will be more readily available
to more farmers. To the extent possible, the HMRP
will conduct on-farm demonstrations involving
varieties multiplied in a givencommunity.

Training. Three in-country training workshops
wereheld:
* Utilizing the Maize Almanac. Thirty-one researchers
and administrators from within NARC, MOA and a
few NGOs attended a two day training course
(28-29Febr uary) and approximately 20 senior
administrators from within NARC and the MOA
(including the Minister) attended a one day
overview workshop (1 March) on the use of the
Maize Almanac.
* Training Trainers of Community-based Seed
Producers. Thirty participants from research,
extension, community groups and NGOs attended
this course held in Rampur, April 4-6.

25
Maize Research Highlights 19992000

* Computer use for data analysis. Held in the
CIMMYT-Kathmandu office, this course was
structured to allow for one-on-one training, with
each participant having access to a computer.
Participants used their own field data as part of the
training. Nine research officers from Lumle (2),
Kabre (2), Pakhribas (2) and Rampur (3) participated
in this training, which was held during the first two
weeks of November.

Two scientists attended the 6-month crop
management research training course in Njoro, Kenya.
The Coordinator of the NMRP, Krishna Adhikari,
attended the one-month, advanced breeding course in
CIMMYT-Mexico in August. Mr. D. B. Gurung, Station
Chief at Dailekh, attended a training course on
participatory rural appraisal techniques in November
in the Philippines. His participation was partially
funded by CIMMYT's Upland Project (IFAD funding).

Challenges and Risks. The Maoist insurgency has
intensified in several areas of Nepal. Nevertheless,
project activities are continuing at all key stations and
associated outreach sites. CIMMYT staff did not visit
Dailekh ARS during the year as a result of security
concerns. A shortage of staff, particularly in Dailekh
and Kabre, constrained the project during the first half
of the year.

Conclusion

The first two years of the HMRP have been devoted
largely to identifying priorities, developing research
strategies, and building research capacity within
NARC. Priorities were established through a systematic
process of meeting with farmers, reviewing geo
referenced data provided by the Nepal Country
Almanac, and seeking advice from experienced
researchers. As a result, a number of research topics
that were not initially targeted by the project have now
beem identified as priorities. The project has been able
to draw on expertise from CIMMYT's global program,
a soil scientist from Africa, an entomologist from
Mexico, and breeders from Thailand and Zimbabwe to
help establish an effective research strategy.

During this period the HMRP brought to Nepal and
tested the most advanced genetic material from
CIMMYT's global breeding programs. Several new
varieties superior to those currently recommended
were identified. Furthermore, the national maize
program now knows where to obtain adapted
materialsand NARC-CIMMYT collaborative varietal
development programs have been established.
Materials from CIMMYT-Zimbabwe are doing
exceptionally well in the mid-hills of Nepal, and more
focused testing of materials from Zimbabwe will allow
for more efficient exploitation of CIMMYT's genetic
resources in the future.

Lack of seed production seriously constrains the
movement of new varieties within Nepal. The project
has been successful in promoting community based
seed production. Although a modest amount of seed is
being produced, the methodology for teaching farmers
how to produce seed within a community is now in
place and well tested. This will increase the likelihood
of new varieties moving beyond the research station
and into the farmers' fields. The project has been able
toestablish a sound foundation upon which to build
insubsequent years.

26
Maize Research Highlights 19992000

Quality Protein Maize:

Improved Nutrition and Livelihoods for the Poor

Hugo Cordova*

Introduction

Maize is a major food for millions of the poor in Africa
and Latin America. During the last few decades,
CIMMYT scientists have developed and improved a
quality protein maize (QPM) that looks and tastes like
normal maize, yields as much or more, and shows
equal or superior disease and pest resistance. But
QPM contains nearly twice the lysine and
tryptophan-amino acids essential for protein
synthesis in humans and monogastric animals-plus
generally mor e balanced amino acid content that
greatly enhances its nutritive value. Research suggests
QPM can help reduce protein deficiencies, particularly
in young children, in settings where maize dominates
diets. In Colombia, Guatemala, and Peru,
malnourished children have been restored to health on
controlled diets using quality protein maize. In
addition, repeated studies in several countries have
shown that pigs or poultry raised on QPM-based
feeds gain weight faster and produce more than
animals raised on normal maize-based feeds.

Since 1997, the Nippon Foundation has helped
CIMMYT bring QPM within reach of millions of
maize farmers and consumers in developing countries
(Table 1). Through the Nippon-funded project "The
Improvement and Promotion of Quality Protein
Maizein Selected Developing Countries," CIMMYT
and its partners have:

* Developed stable, high-yielding, disease-resistant
QPM hybrids and synthetic varieties for diverse
production settings.
* Tested QPM extensively on-farm and in
demonstration trials.

* CIMMYT maize breeder.

* Promoted QPM in countries where maize is a staple
and where the probability of adoption and impacts
is high.
* Enhanced QPM seed production and distribution.
* Provided training on QPM research and
dissemination.
* Conducted trials on the use of QPM in animal feed.

Table 2 provides a detailed accounting of activities
and achievements during 1997-2000. The following is
a summary of the chief aspects, as well as an
examination of the lessons learned and an outline of
future directions.

Progress and Products

Yield. Superior QPM hybrids and varieties identified
through multi-location testing have been evaluated in
more than 40 nations. In results, QPM hybrids often
had a yield advantage of 1.0 t/ha or more over the
best normal hybrid checks (Fig. 1), and yields of open
pollinated varieties (OPVs) of QPM have equaled or
exceeded those of normal maize. CIMMYT researchers
have formed thousands of improved experimental
QPM varieties for future testing and use. The
groundwork has been laid for using DNA markers to
help transfer quality protein genes to elite cultivars of
normal maize. New QPM synthetics9 feature special
characteristics such as low and uniform ear

9 "Synthetics" are open-pollinated varieties (OPVs) formed by inter
crossing 8 to 10 inbred lines known to combine very well (i.e., their
progeny are outstanding) among themselves. Synthetics offer yields
superior to those of normal OPVs but, as with all OPVs, seed from the
previous harvest can be sown the following season without losing
yield or desirable qualities. This is an advantage for poor farmers, who
cannot afford to buy new seed year after year (a requirement in the
case of hybrids, for example).

27
Maize Research Highlights 19992000

placement, resistance to ear rot and root lodging,
and (most notably) levels of tryptophan (0.11% of
the whole grain), lysine (0.475 % of the whole grain),
and protein (11.0% of the whole grain) far beyond
those contained in normal maize (0.05, 0.225, and
8.5%). These features make the QPM synthetics
particularly attractive to farmers.

Converting Normal Elite Lines to QPM. Ten
normal elite lines-parents of high-yielding tropical,
subtropical, and highland hybrids of normal
endosperm-were converted or are in the final
stepsof conversion to QPM. This means that QPM

hybrids with high yield potential will be available for
a range of environments. The news is especially
significant for the highlands, an ecology for which no
QPM varieties are currently available.

Dissemination. Research and certification agencies of
19 countries have released dozens of QPM hybrids
and varieties for use by farmers since 1998 (Table 2).
Releases have been promoted through ceremonies and
field days involving farmers, researchers, VIPs, and
the media. In 1998 six hundred tons of parental seed
for QPM hybrids was produced in Mexico alone, and
seed production methods have been greatly refined.

Table 1. QPM varieties released since 1996.

Name Type Pedigree Country

HQINTA-993
NB- Nutrinta
HB- PROTICTA
HQ- 61
HQ- 31
Zhongdan 9409
Zhongdan 3850
QUIAN2609
Shaktiman-1
Shaktiman-2
ICA
Susuma*
Obatampa*
Nalongo* ?
Obatampa*
BR- 473
BR-451
Assum Preto
Obatampa*
Obatampa*
QS- 7705
GH- 132- 28*
BHQP-542
INIA
FONAIAP
HQ- 2000
In Mexico, 21 hybrids and 5 open
H-441C
H-367C
H-553C
H-519C
H-368C
H-469C
VS- 537 C
VS- 538 C

Hybrid
Open pollinated
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Open pollinated
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
pollinated varieties including...
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Hybrid
Open pollinated
Open pollinated

(CML144x CML159) CML176
Poza Rica 8763
(CML144x CML159) CML176
(CML144x CML159) CML176
(CML144x CML159) CML176
Pool 33 x Temp QPM

Tai 19/02 x CML171
(CML142x CML150) CML176
CML176x CML186
(CML144x CML159) CML176
Across 8363SR
Across 8363SR
Across 8663SR
Across 8363SR

Across 8363SR
Across 8363SR

P62, P63
(CML144 x CML159) CML176
CML161x CML165
(CML144 x CML159) CML176
CML161x CML165

CML186x CML142
CML142x CML150
(CML142x CML150) CML176
(CML144 x CML159) CML176
CML186x CML149
CML176x CML186
POZA RICA 8763
ACROSS 8762

* Sasakawa- Global 2000, a non-governmental organization dedicated to ending malnutrition and poverty in Africa and a leading promoter of
QPM in the region, cooperated with national programs and CIMMYTforthe release of these varieties.

28
Maize Research Highlights 19992000

Nicaragua
Nicaragua
Guatemala
El Salvador
Honduras
China
China
China
India
India
Colombia
Mozambique
Mali
Uganda
Benin
Brazil
Brazil
Brazil
Burkina Faso
Guinea
South Africa
Ghana
Etiopia
Peru
Venezuela
Vietnam

Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico

Quality Protein Maize: Improved Nutrition and Livelihoods for the Poor

CIMMYT's international maize testing unit has
responded to hundreds of requests for QPM seed from
more than 30 countries, as well as annually shipping
nearly 400 trials involving more than 800 hybrids and
varieties to sites throughout the developing world.
Extensive on-farm testing of QPM crosses took place in
Africa in 2000: more than 200 trials were conducted in
11 nations (Angola, Congo, Ethiopia, Ghana, Kenya,
Madagascar, Malawi, Mozambique, Tanzania, Uganda,
and Zambia). In Guizhou Province, one of the poorest
regions of China, a government program provided
farmers credit to buy pigs and raise them on QPM.
Earnings have allowed inhabitants to build houses and
undertake community development activities, in
addition to achieving household food security.
Additional QPM releases are expected in Colombia,
Honduras, India, Peru, Vietnam, Venezuela, Ethiopia,
Kenya, Uganda and Malawi in 2001-2002.

Protein Quality. Lab equipment for enzyme linked,
immunosorbent assay analysis (ELISA; a rapid way to
test for protein quality) was purchased for China,
India, and Zimbabwe, and scientists were trained in its

use. Innearly all trials, QPM hybrids had 70 to 100%
more lysine and tryptophan than their normal maize
competitors. Some new hybrids contain as much
12.5% protein-3.5% more than their normal maize
counterparts. Because QPM is a recessive trait,
normal, non-QPM is dominant. This means that, if
QPM is fertilized by pollen from normal maize, the
enhanced protein quality will be lost. However,
several years of field tests have shown that pollen
contamination of QPM varieties from normal maize
fields is somewhat less than originally feared.
Typically, protein quality in the grain of even the
outermost rows will be reduced on the order of only
10% in a QPM field surrounded by normal maize.
Further inside the QPM plot, little or no protein
quality is lost. This of course can vary significantly,
according to wind speed and direction, and careful
monitoring of protein quality is required in seed
production and maintenance, to keep high standards
of protein quality. When choosing seed for future
sowings, farmers should always select from plants
near the center of theplot.

29
Maize Research Highlights 19992000

The World Food Prize, QPM History, and Partners

Maize breeder Surinder K. Vasal and cereal chemist Evangelina Villegas shared the 2000 World Food Prize for their efforts at CIMMYT
overthe 1970-80s to develop QPM. The Prize is awarded annuallyto individuals who have advanced human development by improving
the quality, quantity, or availability of food in the world. Vasal capitalized on traditional breeding techniques to incorporate a series of
special genes that countered the unwanted side-effects of opaque-2, a gene for protein quality discovered in maize in 1963. To ensure
thatthe value-added protein traitwas retained during crossing and selection, Villegas and her lab group painstakingly measured amino
acid content in the protein of some 20,000 maize grain samples each year. Bythe mid-1980s, the team had developed QPM-a product
much like normal maize, but with nearly double the lysine and tryptophan.

During the 1980s and early 1990s, other CIMMYT breeders-notably Magni Bjarnason and Kevin Pixley-developed high yielding QPM
varieties for several developing country production niches. Sasakawa Global 2000, an international organization thatworks to spread
improved farm technology in Africa, successfully promoted QPM in Ghana and several other African nations. Brian Larkins of the
University of Arizona, USA, has provided valuable assistance in ELISA analysis. Norman E. Borlaug, Nobel Peace laureate and president
of the Sasakawa Africa Association, has strongly endorsed QPM research and use. CIMMYT breeder Hugo C6rdova and colleagues
have spearheaded international QPM development, testing, and dissemination efforts underthe Nippon-funded project.

Partners in this work have included the national maize research systems in Bolivia, Brazil, Central America, China, Colombia, Ethiopia,
Ghana, India, Kenya, Malawi, Mozambique, Peru, Tanzania, Thailand, Uganda, Venezuela, Vietnam, and Zimbabwe; Sasakawa-Global
2000 (SG2000), the Sasakawa Africa Association (SAA), World Vision International (WVI), the Fundaci6n Patino, Maseca, Demasa,
Milpareal, Texas A&M University, and other major non-government organizations.

Future Directions

We will continue emphasizing the development and
testing of new hybrids and synthetics resistant to
diverse biotic and abiotic stresses, as well as exploring
new schemes to shorten the time of conversion of
normal elite lines to QPM.

The CIMMYT Maize Program also participates in two
major projects1" to develop, test, and promote stress
tolerant maize for farmers in sub-Saharan Africa. Both
are incorporating the quality protein trait into the
experimental varieties they develop and adapting elite
QPM for use by farmers in the region.

Finally, from their work on QPM, CIMMYT researchers
have learned the following valuable lessons:

Seed Production. Seed production for QPM hybrids
and varieties should follow the normal and stringent
quality control measures observed to produce high
quality seed of normal maize. In addition, the protein
quality of QPM should be assayed carefully at least
once a year, using techniques such as ELISA and
tryptophan analysis, during all stages of seed
production. It is especially important to monitor protein
quality when producing breeders' and basic seed, to
avoid losses of lysine and tryptophan in subsequent
steps (seed increases, commercial seed production,
farmers' commercial grain).

Promotion. New tropical and subtropical QPM
hybrids and varieties compete well in quality and
yield potential with normal seed industry offerings for
those ecologies. Nonetheless, active promotion using
varied approaches-on-farm trials, verification trials,
demonstration trials-is required to familiarize
farmers with the best performing and adapted hybrid
or variety for a given production setting. A minimum
of two years of on-farm testing and verification are
needed. Hybrids can be released in the third year
before planting season starts and demonstration plots
are planted. Varieties should never be released
without testing, and this must be done in their area of
adaptation (for example, subtropical varieties should
not be testing in a tropical region). Great care must be
taken with seed quality: forexample, germination
should be checked before planting trials.

Seed production should be associated with the
promotion of hybrids from the outset. Commercial
seed producers should be involved in the transfer of
QPM technology, to ensure successful promotion, as
has been the case in El Salvador and China. The
potential interest in QPM of a range of other
commercial organizations has been used to enlist their
participation in promoting this specialty maize. These
include farmer associations (such as Agroportuguesa
in Venezuela), swine growers (Mexico), the milling
industry (El Salvador, Guatemala, Honduras), and the
poultry industry (Colombia).

10 See "Stress-tolerant Maize for Farmers in Sub-Saharan Africa," p. 1.

r

L. America

* QPM hybrids

3 Normal hybrids

Figure 1. Yield of QPM and normal maize hybrids in tests at 33 locations in Africa, Asia, and Latin America, 2000.

30
Maize Research Highlights 1999 2000

I

Quality Protein Maize: Improved Nutrition and Livelihoods for the Poor

Table 1. Activities and achievements in QPM research, testing, and promotion, 1997-2000.

1997 1998 1999 2000

Dissemination Brazil releases one Releases in Benin, Burkina National programs release 12 QPM National programs release a
yellow grain QPM hybrid Faso, and Guinea by hybrids and 4 open pollinated hybrid in Guatemala and OPVs in
and Ghana two white Sasakawa-Global 2000 varieties in Mexico; 1 hybrid each Mozambique and Uganda.
grain QPM hybrids, and in Brazil. in China, El Salvador, Guatemala, Produce basic seed of QPM for
and Peru. CIMMYT ships seed to demonstrations in China, Ethiopia,
29 countries in response to more Ghana, India, Nicaragua, Peru,
than 180 requests. Vietnam, and Zimbabwe.

Testing Brazil, Ethiopia, Well underway in Brazil, Superior hybrids and open- More than 200 trials conducted in
Guatemala, India, Mexico, Colombia, El Salvador, pollinated varieties of quality Angola, Congo, Ethiopia, Ghana,
Mozambique, Ghana, Ethiopia, Ghana, Guatemala, protein maize (QPM) evaluated Kenya, Madagascar, Malawi,
South Africa, and Thailand India, Mexico, Mozambique, in more than 30 nations often Mozambique, Rwanda, South Africa,
Tropical and subtropical South Africa, Thailand, and had a yield advantage of one Tanzania, Uganda, Zambia, and
QPM hybrids in Mexico, Zimbabwe. Begun in Bolivia, ton or more per hectare over Zimbabwe. Yield and disease
India, Zimbabwe, South Honduras, Malawi, Mali, the best normal maize hybrids, resistance atleastcomparable to
Africa, and Mozambique Nicaragua, Peru, the QPM hybrids have 70 to the best African materials.* Field
significantly out-yield Philippines, and Uganda. 100% more of the essential test results showthat pollen
commercial hybrids. Tropical and subtropical amino acids-lysine and contamination of QPM varieties
QPM hybrids again yield tryptophan-than their from normal maize is far less than
much more than commercial normal maize competitors. originallyfeared. Lab tests show
checks and possess superior some new QPM hybrids contain
protein quality, as much 13.5% protein-at least
30% more than normal maize.

Promotion Two field days in Mexico Gala ceremonies and field days in The award of the World Food Prize
attended by hundreds (farmers, Mexico, El Salvador, and China; to the scientists who developed
agriculture secretaries, nearly 2,000 farmers, as well as QPM at CIMMYT during 1970-85
researchers and directors, researchers and VIPs (including focuses global attention on QPM.
agricultural industrialists, among CIMMYT DG and Nippon
others) result in Mexican plans representatives) participate.* The
to launch a major QPM CIMMYT Annual Reportfeatures a
production and promotion major story on QPM.
program in early 1999.

Germplasm Increase seed of best 1991 Produce more seed of the best Form more than 1,500 new, Newtropical QPM synthetics offer
development, QPM lines for evaluation tropical and subtropical hybrids experimental QPM hybrids. Increase yields superiorto those of normal
formation, by national programs. and varieties for extensive seed of 20 key synthetics and of 28 varieties but allow seed to be saved
and seed Improve resistance of evaluation at more than 100 inbred parents.* Produce 17.5tons and sown the following season-
production QPM lines to crop diseases. locations in 10 priority countries of parental seed of the new QPM an advantage for poorfarmers
Field-test 600 inbred during 1999. Produce seed hybrid, Zhongdan 9409, in China; who cannot afford to buy hybrid
lines and develop hybrids, of one SC hybrid 9009 in China. distribute 67 tons of hybrid seed seed. CIMMYT develops QPM
Form 1,000 new in Guizhou Province.* CIMMYT versions of its most important
inbred lines. delivers 2.5 tons of hybrid progenitors tropical and subtropical inbred
and single-cross hybrid seed to Mexican lines and is doing the same for
agencies, which produce 500tons of highland lines.
registered seed of hybrids and va rieties.

Laboratory Identify molecular markers Continue to identify molecular Purchase lab equipmentfor enzyme Backcrossing assisted by molecular
methodologies for protein quality and markers forthe genes associated linked, immunosorbent assay analysis markers to convert normal, tropical
kernel hardness genes. with protein quality and kernel (ELISA; a rapid wayto testfor protein white inbred lines (CML 264 and
hardness.* Begin backcrossesto quality and a crucial componentof CML273),to QPM.
transfer QPM genes into outstanding QPM breeding) for India and China,
conventional inbred lines, train scientists in its use.

Training Two visiting scientists-one Three visiting scientists -one Hold training course on seed production Training events on various aspects
from Mexico and one from each from Mexico, Ghana, and in Zimbabwe for researchers from of QPM research were conducted
Ghana-work on QPM Ethiopia participate for several sub-Saharan Africa and Brazil.* The by CIMMYT staff in Africa, Asia,
at CIMMYT. months in QPM research at Project helps support QPM research Latin America and at CIMMYT
CIMMYT of a visiting scientistfrom Ethiopia. headquarters.

31
Maize Research Highlights 19992000

Storage Pest Resistance In Maize

David Bergvinson*

Maize is a major food crop in Africa and the Americas
as well as a feed crop for these regions and Asia.
Genetic gains in yield have been achieved but these
gains are not always realized at the farm level due to
the challenging environments maize faces. One
important factor that reduces yield and yield stability
is the pressure placed on the crop by insect feeding
throughout the cropping cycle (Fig. 1). During the
vegetative and grain filling stages, insects such as
stem borers and armyworm cause on-farm losses in
the range of 5 to 30%. Additional losses are caused by
several different post harvest pests, with some areas
such as the lowland tropics of Mexico suffering 100
percent kernel damage and 30% weight loss during 6
months of storage. This report describes CIMMYT's
work to develop insect resistant maize and related
technologies, and ends by focusing on significant
recent advances in research on resistance to insect
pests of stored grain.

~:ii j:(:.-.44 : -,

*1*' II

An Overview of Entomology Research

The Maize Program is well equipped for research on
resistance to insect pests. In addition to its extensive
collections of tropical maize seed, representing a
considerable portion of maize genetic diversity, the
Program also has the required infrastructure and
technical expertise to screen germplasm for resistance.
Even so, developing insect resistant maize is a difficult
task: resistance is a polygenic trait (seven important
QTLs have been identified) and proper screening
requires that healthy insects for infestation become
available at the crop development stages when
experimental plants are most susceptible.

The Program is currently using two strategies to
increase the level of insect resistance: 1) eliminate the
most susceptible germplasm from our main breeding
populations, and 2) develop source germplasm with

* Entomologist, Maize Program.

\: .I" !I-,, rn X4A .,lt

Figure 1. Distribution of important insect pests of tropical maize in the field.

32
Maize Research Highlights 19992000

I r
'
r.

r
i"lRi ig~ Bt~UIF
;' ~; ""
~'"' ""'

Storage Pest Resistance in Maize

elevated levels of resistance for incorporation into
CIMMYT's elite lines and populations (Fig. 2). Thus,
our main breeding populations have become more
tolerant to insect pests and our source populations
have improved in their agronomic performance. Since
CIMMYT has only one insect rearing facility for borers
and armyworm, the entomology unit also screens
lines developed by our regional programs. During
evaluation, elite lines developed at outreach offices are
crossed to insect resistant lines for selection under
insect pressure as well as adaptation to regional
stresses (i.e. local diseases, drought). This process of
"shuttle breeding" is an effective means of developing
insect resistant germplasm that is adapted to the target
environment.

There have been good gains in developing insect
resistant maize populations, with CIMMYT
germplasm serving as a source material for not only
tropical maize but also temperate maize (Fig. 3). The
entomology unit uses a breeding process called S3
intra-population improvement to concentrate the
resistance alleles into maize lines. Lines thus produced
are transferred to breeders in Mexico and regional
offices for incorporation into breeding populations.

The resistance mechanism has been well
characterized through research by CIMMYT's
entomology unit and through molecular mapping
in collaboration with the CIMMYT Applied
Biotechnology Center. The two major components
involve reduced leaf nitrogen content (below 2.3%
N) and increased epidermal cell wall toughness of
the leaves. The first mechanism is not practical,
because reducing N content in plant tissue also
reduces yields. However, leaf toughness does not
pose a risk to yield, as it involves a thicker
epidermal cell wall (Table 1) and higher levels of
phenolic dimers localized in the cell wall. We have
utilized this information to identify breeding
populations that have the best chance of producing
insect resistant germplasm that yields well. This
technology is now being used in Kenya to assist in
the selection of lines to be considered in the Insect
Resistant Maize for Africa (IRMA) project. The
criterion is that they combine both conventional
insect resistance with transgenic (Bt) resistance to
deliver a durable and effective level of stem borer
resistance for Kenyan farmers.

11Q Breeders

TC ror p tecnitot 6"
hctcrefic pollmlatOTIF V

Brcc&&g populxmtbo
hidestiled Its. S, stige-
bc. -eased ievef Of ren'zstance
/Tr'-;ircy rn FOP. & Diel

Entoms. hutk

SomkC pOputiilunmi
S3 RS under bdesntdon
MIRT, MBR+4 Speeil hait

4 t
=4tlir davmkid
arid taurnfirre4

Elite lies testeCd i "ItJTs"
under artficdal I estaton.
&a ineu wesd Po uYlinr jytebrmatwiin

Products: Populations Synthetics Lines

Olllltrea Breeders

Cmucss ens di to
/ 3daptVd gcnmplawn
Scruned by NARS

Elitk tins tcskAd in LETs"
undt ordidlmil Imfsidou.
Best Enrcs cirosscd to IR fini

Sl-S Iii s JcwdopcAid unrm
Infrtatiton =4I4so to OR
1Shidtkc Brecdinge

Hybrids

Figure 2. The CIMMYT Maize Program's approach for developing insect resistant germplasm (LET = line evaluation trial).

33
Maize Research Highlights 19992000

In developing countries the maize crop normally
faces many stresses simultaneously. For this reason,
research was initiated to look at the interactions
between drought and the effects of infertile (low
nitrogen) soils and yield reductions associated with
insect pests. Our original work focused on superior
performance (i.e., reduced insect attack and percent
yield losses) under zero nitrogen (i.e., where no
fertilizer was applied). We have since worked with
the timing of optimal nitrogen rates to identify the
optimal timing of nitrogen application to reduce
insect establishment and increase yield. Delaying
nitrogen applications to two weeks before flowering
reduced insect attack and increased yield but also
increases the incidence of ear rots. For regions
where insect damage is severe and nitrogen
limiting, delayed applications may be considered.
Another important interaction identified is the
synergism between drought and stem borer damage
in reducing yield (Fig. 3). From this work, it is
evident that drought tolerance and stem borer
resistance are an important combination for African
germplasm, especially in regions were insect
pressure is consistent. We are recycling the best
drought tolerantlines fr om CIMMYT's Zimbabwe
program with insect resistant lines form Mexico to
address thisneed.

Regarding quality protein maize (QPM), one limitation to
adoption has been its susceptibility to biotic stresses, the
most notable being weevils during storage. Testing of
experimental QPM varieties for weevil resistance has
been initiated to identify varieties with good levels of
resistance (see more below). There are QPM varieties that
show good better weevil resistance than conventional
hybrids. Testing for weevil resistance will be an
important component in QPM characterization (Fig4).

The Entomology Unit is also involved in testing and
developing transgenic maize containing the Bacillus
thuringiensis (Bt) gene. This involves the testing of
putative transformed events, looking at the rate of insects
developing resistance, designing insect resistance
management strategies for developing countries, and
estimating impacts on non-target organisms. This work
links with that of the IRMA project, which focuses on
developing insect resistance maize for Kenya by using
both conventional and transgenic sources of insect
resistance. In Kenya, farmers report losing 15% of their
maize harvest to stem borers, equivalent to 400,000 t of
maize each year valued at US$ 90 million. Farmers in
some areas have reported losses as high as 45%. By
bringing conventional resistance together with Bt
resistance, we can offer maize with efficient and durable
resistance for tropical ecologies where insect associated
losses are most severe.

.mI

Te

41 1

-u

rmwas NmEM MAImarM win C1 a mirn= e *mr& ETOMW a impa"

population over cycles of selection.

34
Maize Research Highlights 19992000

Storage Pest Resistance in Maize

Research on Storage Pest Resistance

Although many modern maize varieties and hybrids
possess improved agronomic performance and
tolerance to abiotic and biotic stresses, traits that
contribute to improved grain storage have been
largely ignored. This characteristic is particularly
important in developing countries, where grain is
often for domestic use and stored under adverse
conditions. Insect pests that attack stored grain tend
tohave rapid rates of r production and both
consumegrain and contaminate it with insect parts
and excrement. For maize, these losses usually
amount to 5-15% in developing countries, with on
farm surveys in Mexico generating a mean of 30%
kernel damage largely by the maize weevil (Sitophilus
zeamais) and the larger grain borer (Prostephanus
truncatus) (Tigar et al. 1994).

Researchers have known for more than two decades
that genetic variation for resistance to storage pests
exists in maize. Widstrom et al. (1975) investigated the
inheritance of resistance to maize weevil with 80
maize inbred lines in a no-choice study. Maternal
dominance effects were found important but not
cytoplasmic effects. Using a 10-line diallel, Tipping et
al. (1989) found that, under no-choice conditions,
general combining ability was more important than
specific combining ability. Additional studies that
have used germplasm with more diversity have also

20 -

S15-

10 -

Normal

S . .

Figure 4. Characterization of quality protein maize (QPM)
for kernel hardness as a means of identifying varieties
prone to attack by post harvest pests.

confirmed the heritability of weevil resistance but
the relatively low, broad-based inheritance observed
for this trait would imply slow progress in moving
the trait into elite germplasm (Li et al. 1998; Derera
et al. 2001a,b). The challenge now is to utilize this
variation in modern breeding programs focused on
tropical maize normally stored under adverse
conditions.

Early research to elucidate the mechanism of
resistance has found through fluorescence
microscopy (Serratos et al. 1987) that the pericarp of
resistant maize genotypes was highly fluorescent.
This was attributed to high concentrations of
hydroxycinnamic acids (simple phenolics) located
within the pericarp. These phenolics are bound to
the arabinoxylans within the cell wall. Subsequent
research using 15 CIMMYT pools and populations
correlated maize weevil resistance (number of eggs
laid, number of progeny, Dobie Index, grain
consumption) with E-ferulic acid, protein content,
and kernel hardness (Classen et al. 1990). Screening
of Mexican landraces allowed the identification of
resistance sources, with the ancient indigenous
races, such as Sinaloa 35 and Yucatan-7, being
among the best (Arnason et al. 1994).

An understanding of the inheritance of
biochemical/biophysical factors has been achieved
by generations mean analysis (Serratos et al. 1997).
This study estimated genetic variation using linear
models that related biochemical and biophysical
factors to susceptibility indices of selected
genotypes. Dominance of endosperm-pericarp for
phenolics in the grain and dominance of the
pericarp for phenolics, maximum kernel force of
compression and index of susceptibility were highly
significant, indicating that phenolics do have a role
in weevil resistance expressed in the pericarp.

Our research is now focused on furthering our
understanding of the limitations of these
biochemical resistance factors in maize, constructing
molecular maps to identify quantitative trait loci,
and large-scale screening of CIMMYT germplasm
(maize and wheat) to identify new elite sources of
resistance and eliminate germplasm that is
extremely susceptible prior to line release. These
activities will be discussed below.

35
Maize Research Highlights 19992000

~CIICON
~~~~
rnrnrnrn
IIII
uuuu

""5~~
~~ONO
LOLOLOLOLO
CIICIICIICIICII
CIICIICIICIICII
~~~~~
IIIII
uuuuu

Biochemical basis of kernel resistance to post
harvest pests. Given the demonstrated importance of
kernel compression (Serratos et al. 1993), the
entomology unit was interested in developing a rapid
surrogate method to screen maize kernels for this trait.
Using a Tricor Systems Inc. Model 921A Force
Displacement meter, a methodology was developed to
measure the peak kernel force. The meter was fitted
with a 22Kg load cell and a 0.8mm dia. probe with a
rounded tip. Grain was equilibrated at 75% relative
humidity and 270C for 2 weeks prior to measuring.
Under these conditions germplasm could be screened
with good separation occurring between maize
genotypes, as evidenced by the screening of QPM,
which has the opaque-2 mutant that delivers higher
levels of tryptophan and lysine but results in a soft
endosperm and susceptibility to weevils (Fig. 4).

Using this technique, QPM varieties can now be
screened for hard endosperm, with segregating
populations being improved for kernel hardness. This
is possible because the same kernels that areused for
evaluation can be regenerated to accelerate breeding
progress in endosperm modification. The germination
rate after kernel measurement is ca. 85-90% when
kernels are incubated at 300C and 100%RH for 3 days
prior totransplanting.

100

S80

, 60
E-

S40

S20-

0

Given the importance of kernel hardness and
theability to measure e this trait rapidly in the lab, our
group conducted a study to quantify the relationship
between grain moisture content (GMC), kernel
hardness, and resistance to
S. zeamais and P truncatus. Figure 5 shows the
relationship we observed using environmental growth
chambers set at different levels of relative humidity
(40, 60, 80 and 100%) and 27C. At a GMC below 12%,
the resistant genotype (Population 84) derived from
Caribbean and Cuban bank accessions provided
effective control for both insect species. However, once
the GMC reached 16% the resistant and susceptible
(CML244xCML349) entries showed similar damage
levels. Kernel hardness also dropped with increasing
GMC, indicating the limitation of this resistance
mechanism.

These results highlight the importance of grain
conditioning prior to storage. CIMMYT is working to
develop low cost grain drying systems as part of an
integrated post harvest management strategy for
resource poor farmers.

The relationship between kernel hardness and
biochemical factors is now being refined, with the
advent of more sophisticated HPLC techniques for
quantifying phenolics. One group of phenolic

20.00 100

15.00

E 60
10.00 ,
E 40
5.00 2

0.00 0

10 12 14 16

Grain moisture content (%)

10 12 14 16 18

Grain moisture content (%)

Figure 5. Relationship between insect resistance [solid lines] and kernel force (Kg/mm2) [dashed lines] using a resistant
(Population 84) [black lines] and susceptible (CML244xCML349) [grey line] genotypes of maize. Graph A) Prostephanus
truncatus and B) Sitophilus zeamais.

36
Maize Research Highlights 19992000

A)
A)' Force(R)=- .02x+30
R2=1
Damage(S)=3x +4 6'x +
R2 =0.8482 .
Force(S)=-1.15x+29
R 2= I
-- --\

Damage(R)=13x-142
R2 =0.98
I I I

Storage Pest Resistance in Maize

compounds that have received considerable attention
in the past decade are the phenolic dimmers which
cross-link hemicelulose within the cell wall. Difeluric
acid is one such dimmer and is under enzymatic
control (Fig. 6).

Given the genetic and biochemical compositions of the
different kernel tissues endospermm, germ, pericarp),
our group has used tissue-enriched fractions
generated from a peril mill to conduct biochemical
research. The reason for this is the dilution associated
with the endosperm that constitutes 70% of the
sample compared to around 5-8% for the pericarp.
Using this technique, phytochemical analysis as
described in Arnason et al. (1994) was used to
correlate the different putative resistance factors with
kernel resistance against
S. zeamais for each tissue type endospermm, germ,
pericarp). The study consisted of 7 genotypes
representing a wide range in resistance (Table 1).

*il-n1

Ferulic acid

Dehydrodiferulic acid

Figure 6. Peroxidase-mediated formation of diferulic acid
formed in the cytosol and used as a cross-linking agent in
cell wall formation.

Table 1. Correlation of weevil resistance and putative resistance factors using enriched-tissue fractions from seven
maize genotypes.

Damage
by Kernel Total
Tissuet S. zeamais hardness Nitrogen Fiber Sugars DFA

Embryo
Kernel hardness -0.71
Nitrogen -0.61 0.23
Fiber 0.11 -0.57 0.28
Sugars 0.42 -0.61 0.22 0.88*
Total DFA 0.45 -0.92* 0.00 0.82 0.75
Ferulic acid 0.52 -0.83 0.28 0.68 0.81 0.84

Endosperm
Kernel hardness -0.97**
Nitrogen -0.70 0.63
Fiber 0.53 -0.56 0.15
Sugars 0.39 -0.29 0.12 0.79
Total DFA 0.40 -0.47 -0.72 -0.27 -0.48
Ferulic acid 0.41 -0.40 -0.84* -0.51 -0.51 0.86**
Quality Index 0.03 -0.09 0.28 0.69 0.55 -0.11

Pericarp
Kernel hardness -0.97**
Nitrogen 0.89* -0.95**
Fiber 0.19 -0.20 0.00
Sugars 0.86* -0.92** 0.91** 0.05
Total DFA -0.91** 0.86* -0.82* -0.12 -0.63
Ferulic acid -0.80 0.71 -0.55 -0.51 -0.42 0.88*

t Correlations in bold have a P-value <0.07, P<0.05, **P<0.01.

37
Maize Research Highlights 19992000

Thedifer ulic acids were most important for the
pericarpexpr session of resistance and included 5-5DFA,
8-0-4DFA, and 8-5DFA.

Molecular mapping of weevil resistance in tropical
maize. Based on early studies of CIMMYT populations,
two varieties were selected under weevil infestation for
improved resistance. Nine mapping populations were
created for both white and yellow tropical maize, with
one F2 population being selected based on the
phenotypic range for kernel hardness and weevil
resistance. This mapping population consisted of two
lines derived from Population 28 (yellow tropical) to
form an F2: mapping population: 1) Muneng-8128
COHC1 18-2 1 1 with moderate level of resistance and
2) line CML290, which was susceptible. The population
consisted of 163 F2 families that were selfed to generate
F3 lines that were subsequently bulk increased for
phenotypic characterization. To generate the molecular
map, 89 restriction fragment length polymorphisms
(RFLPs) and 196 simple sequence repeats (SSRs) were
used which showed clear polymorphism. Preliminary
results from this mapping effort are shown in Table 2.

Conclusions

Maize germplasm with improved resistance against
storage pests is clearly in high demand among small
scale farmers in tropical counties. CIMMYT has made
progress in meeting this demand by identifying and
developing source germplasm and new screening
methods to advance germplasm improvement for

Table 2. Quantitative trait loci for weevil resistance and
putative resistance factors in a tropical yellow maize
population (Population 28).

Chr. Dist. LR Marker Trait

1 42 12.07 bnlg1007 Kernel hardness
3 261 12.73 umc 63 Dobie Index
4 274 18.09/19.52 bnlg 1917 No.Weevils, Dobie
Index
5 62 12.05 Phill13 Kernel Damage
5 70 12.39 phill13 Dobie Index
6 33/49 10.3/11.3 bnlg1538 Kernel Damage/Loss
7 180 12.71 umc149 Kernel hardness

resistance in maize to post harvest pests. With the
development of source germplasm, biochemical
studies characterized these sources of resistance and
identified limitations in their use. Divergent selection
studies are in progress to define the possible gains
offered by conventional resistance to storage pests.
Graduate students collaborating with CIMMYT have
confirmed the importance of additive, non-additive,
and maternal effects for weevil resistance. This has
assisted in developing weevil tolerant hybrids, using
the resistant line as the female parent in hybrid seed
production. Lines have been identified that not only
serve as a source for weevil resistance but also for
resistance to grey leaf spot and maize streak virus,
two diseases that limit maize productivity in sub
Saharan Africa, for use in recycling elite lines targeted
for Africa. QPM varieties have also been screened to
identify the most promising germplasm for weevil
resistance.

Understanding the biochemical basis of insect
resistance is important for both food safety and to
determine the potential limitations of resistant
sources. Good correlations between insect resistance
and kernel hardness are also correlated with elevated
levels of diphenolic acids located within the pericarp
of the kernel. Kernel hardness as a resistance
mechanism is limited by grain moisture content, with
levels above 16% leading to susceptibility in resistant
genotypes. This finding was important as it
emphasized the importance of grain conditioning in
delivering an integrated storage management
package to resource poor farmers.

The development of a mapping population has
enabled some putative QTLs to be identified, with a
long-term goal of identifying robust QTLs for use in a
marker assisted selection (MAS) program to rapidly
incorporate weevil and larger grain borer resistance
into elite lines targeted for tropical climates. The
most efficient strategy for using MAS and
conventional screening has yet to be defined, but
clearly both methods are important in delivering elite
germplasm which has a good level of resistance to
post harvest pests.

38
Maize Research Highlights 19992000

Storage Pest Resistance in Maize

Acknowledgments

The author gratefully recognizes the contributions of
the following colleagues to the results described in
this report: S. Garcia-Lara, CIMMYT research
assistant; and A. Ramputh, A. Burt, and J.T. Arnason,
all three of the Department of Biology, University of
Ottawa, 30 Marie Curie, Ottawa, Canada K1N 6N5.

References

Arnason J.T, B.Baum, J. Gale, J.D.H. Lambert, D.Bergvinson, B.J.R.
Philogene, J.A. Serratos, J. Mihm, and D.C. Jewell. 1994. Variation
in resistance of Mexican landraces of maize to maize weevil
Sitophilus zeamais, in relation to taxonomic and biochemical
parameters. Euphytica 74: 227-236.
Classen D., J.T Arnason, J.A. Serratos, J.D.H. Lambert, C. Nozzolillo,
and B.J.R. Philogene. 1990. Correlation of phenolic acids content
of maize to resistance to Sitophilus zeamais, the maize weevil in
CIMMYT's collections. J Chem. Ecol. 16:301-315.
Derera, J., K.V Pixley and P. Denash Giga. 2001. Resistance of maize
to the maize weevil: I. Antibiosis. African Crops Science Journal 9:
431-440.
Derera, J., P. Denash Giga and K.V Pixley 2001. Resistance of maize
to the maize weevil: II. Non-preference. African Crops Science
Journal 9: 441-450.
Li, R., M.S. Kang, O.J. Moreno and L.M. Pollak. 1998. Genetic
variability in exotic x adapted maize (Zea mays L.) germoplasm
for resistance to maize weevil. Plant Gen. Res. Newsletter 114:22-25
Serratos, J.A. A. Blanco-Labra, J.T. Arnason, and J.A. Mihm. Genetics
of maize grain resistance to maize weevil. Pp. 132-138. In: Mihm,

J.A. 1997. Insect Resistant Maize: Recent advances and Utilization.
Proceedings of and International Symposium, 27 Nov.-3 Dec., 1994,
Mexico D.F. CIMMYT.
Serratos, J.A., J.T. Aranson, C. Nozzolillo, J.D.H. Lambert, B.J.R.
Philogene, G. Fulcher, K. Davidson, L. Peacock, J.Atkinson, and P.,
Morand. 1987. Factors contributing to resistance of exotic maize
populations to maize weevil, Sitophilus zeamais. J. Chem. Ecol. 13:
751-762.
Serratos, J.A., A. Blanco-Labra, J.A. Mihm, L. Pietrzak, and J.T.
Arnason. 1993. Generation means analysis of phenolic
compounds in maize grain and susceptibility to maize weevil
Sitophilus zeamais infestation. Can. J. Bot. 71:1176-1181.
Tigar, B.J., PE. Osborne, G.E. Key, M.E. Flores-S and M. Vazquez-A.
1994. Insect pests associated with rural maize stores in Mexico
with particular reference to Prostephanus truncatus (Coleoptera:
Bostrichidae).J. Stored Prod. Research 30:267-281.
Tipping, PW., P.L.Cornelius, D.E. Legg, C.G. Poneleit and J.G.
Rodriguez. 1989. Inherence of resistance in whole kernel maize to
oviposition by the maize weevil (Coleoptera: Curculionidae).
J Econ. Entomol. 82:1466-1460
Widstrom, N.W., W.D. Hanson and L.M. Redlinger. 1975. Inherence
of maize weevil resistance in maize. Crop Sci. 15:467-470

39
Maize Research Highlights 19992000

The CIMMYT Maize Program in 2000

Shivaji Pandey

There have been important changes in CIMMYT's
Maize Program in recent years; they are briefly
described here.

First, some general information about the extent of
global maize production. Of the 100 million ha of
maize planted in developing countries, about 42
million ha are planted in Asia, 30 million ha in Latin
America, 26 million ha in Africa, and 2.5 million ha in
West Asia/North Africa. In these regions, 50 million
ha are in the lowland tropics, 18 million ha in the
subtropics and tropical midaltitudes, 6 million ha in
the tropical highlands, and 26 million ha in temperate
ecologies. CIMMYT focuses mainly on non-temperate
maize, as much of the technology for temperate maize
is provided by the private sector.

In early 1998, we examined where we were, where we
needed to go, what we needed to do, and with whom,
to better serve the resource-poor maize farmers. One
outcome of this exercise was the document,
"CIMMYT's Maize Program: Strategic Directions, 1998
and Beyond." Basic principles described therein
include the following:

* The Maize Program exists to work with partners to
develop and distribute technologies appropriate for
maize systems operated by resource poor farmers
and to promote increased and sustainable maize
production in developing countries, with the aim of
meeting the growing demand for this cereal.
* Our priorities and niches should be determined by
1) those needs of our partners for which few or no
suppliers exist and 2) what we can do more
efficiently than our partners and provide to them at
a lower cost or no cost at all.
* Our research, products, and services should
improve food security, help alleviate poverty, and
preserve natural resources in developing countries.

Here is what we had going for us:

* One of the largest functional maize gene banks,
where we are preserving, regenerating, evaluating,
and classifying more than 21,000 maize seed
collections from different parts of the world,
especially Latin America and the Caribbean.
* A large array of improved maize germplasm (gene
pools, populations, OPVs, lines, and hybrids),
suitable for developing countries.
* The largest public maize research and collaboration
network through our international testing, training,
and visiting scientist programs, involving the
support and collaboration of nearly 4,000 national
program scientists from 100 countries.
* We had highly experienced and dedicated maize
scientists located strategically throughout the world.
* We had support from excellent scientists in
CIMMYT's Economics Program, Natural Resources
Group (NRG), and Applied Biotechnology Center
(ABC), as well as highly qualified and motivated
support and administrative staff.
* We had the facilities and equipment needed to
develop appropriate technologies efficiently.
* We had the trust, confidence, respect, and support of
partners, donors, leaders, and the CIMMYT Board of
Trustees.

We were doing many things right and they needed to
continue, but we also needed the following:

* A strengthened genetic resources and pre-breeding
(development and improvement of gene pools,
novel crosses between improved and exotic
germplasm, among other things) unit, uniting the
two activities.

* Director, CIMMYT Maize Program.

40
Maize Research Highlights 19992000

The CIMMYT Maize Program in 2000

* A balanced germplasm development and
enhancement program that provided partners with
the means to meet farmers' needs-that is, high
yielding, stress tolerant, agronomically desirable
open pollinated varieties (OPVs) and hybrids-and
that used an appropriate combination of modern
and traditional technologies to do so.
* Greater balance and complementation between
outreach and headquarters activities based on
comparative advantage and allowing for the more
efficient development and distribution of
technologies and enhancing interactions with
partners.
* A revived, aggressive, and pro-partner international
testing unit and germplasm distribution system.
* Increased cooperation with the CIMMYT Economics
Program, the NRG, and the ABC to enhance
research efficiency, priority setting, and technology
targeting and maximize spill-over benefits.
* Greater cooperation with partners, especially
resource-endowed public partners, to increase the
efficiency of germplasm and human resource
development.

In less than three years after the above assessment, we
are pleased to report gratifying progress on all counts.
A few highlights:

Strengthened Genetic Resources and Pre-Breeding.
There are few alternate suppliers of these two services,
even though germplasm is the backbone of any
breeding program. We asked the head of our gene
bank to coordinate both activities and provided him
with additional resources and personnel. Gene pools
that were shelved have been brought back and new
ones synthesized for major maize ecologies in
developing countries. Twelve gene pools for the
tropical lowlands and eight for the subtropics and
midaltitudes are already available and are being
improved using reciprocal recurrent selection. Ten
gene pools for the highlands are being developed.
Novel genotypes are being developed for breeders by
crossing desirable bank accessions with elite CMLs,
much like what is being done under the US
Germplasm Enhancement of Maize Project (GEM)

project. Some of these materials have been passed on
to the breeders, and superior gene pool fractions will
also begin to flow into breeding programs shortly.

Balance in Breeding. We agreed that temperate maize
areas in developing countries were well served by our
private and public partners and our strength was in
germplasm for the lowland, highland, and
midaltitude tropics. In addition, biotic and abiotic
stresses, unfavorable policies, poverty, and others
factors limit maize average yields in developing
countries to only 2.9 t/ha (1.9 t/ha, if China, Brazil,
and Argentina are excluded). Private organizations
have historically focused less on research aimed
directly at enhancing abiotic stress resistance, the
public sector generally lacks the expertise or resources
to do it, and non-government organizations are
usually not research-oriented. Therefore, this must be
one of the most important activities of our program.
Today, stress and non-stress activities are integrated in
our breeding research. Other changes include the
following:
* Approximately 60% of the maize area in developing
countries is planted to improved germplasm; 47% to
hybrids and 13% to OPVs. Fifty-three percent of the
farmers do not use hybrids, either because they
cannot afford them or because suitable hybrids are
not available. Poor and subsistence farmers in the
marginal environments require stress tolerant, stable
performing OPVs and hybrids and low-cost soil
fertility management techniques. Commercial
farmers in favored environments require profit
enhancing technologies based on high-yielding,
stable performing, stress tolerant and input
responsive hybrids and accompanying agronomic
practices. Reflecting these divergent needs, today
the Program devotes about 55% of its efforts to
hybrids and 45% OPVs.
* We agreed that some of our old germplasm, which
no longer served the needs of our partners, needed
to be shelved and new materials developed. We
needed to switch to reciprocal recurrent selection
based on heterotic populations to exploit heterosis.
We have done both.
* We are now developing more uniform, productive,
and stress tolerant synthetics, using inbred lines.

41
Maize Research Highlights 19992000

* For line development, we said we would use 60%
pedigree breeding, 20% molecular-assisted line
enrichment, and 20% selfing in improved
populations and synthetics. We are almost there.
* We are doing more to develop and improve maize
with enhanced levels of protein quality, zinc, and
iron.
* We have developed and are following a new policy
on the release of inbred lines. Among other things, it
limits the number of lines released to only the best
and most uniform, and stipulates that all lines must
be made available with specific information on their
adaptation and performance to facilitate their use by
our partners.
* We wanted to address food vs. feed issues with
maize. It is a very difficult task, and the Economics
Program is leading a project for Asia that will shed
light on the issue, which is more important in this
region than in other parts of the world.

Division of Labor Between Outreach and
Headquarters. We agreed that we must have strong
programs at both the outreach and at headquarters. To
avoid duplication of effort and ensure proper focus and
coordination, we did the following:
* Because much of our impact to date comes from
global public goods germplasm, research methods,
and information do not recognize political or
geographic boundaries-our scientists at
headquarters would continue to:
1. Develop germplasm, research methods, and
information that are global in scope; i.e., they are
useful to our partners in Africa, Asia, and Latin
America.
2. Participate in and support research, training, and
networking activities of outreach scientists.
* Outreach scientists would complement the
headquarters efforts in technology development and
training, especially in areas that cannot be handled in
Mexico and where national programs require
CIMMYT support. This slightly reduces research and
increases development work (e.g., on-farm research,
mother-baby trials, participatory research, seed
production). Specifically, outreach scientists would:

1. Adapt and fine-tune germplasm, information,
and research methods developed at
headquarters.
2. Increase seed of superior germplasm from
headquarters and outreach programs and
provide them to our partners.
3. Conduct strategic agronomic and systems
research in collaboration with partners.
4. Organize regional trials, using superior materials
from headquarters, their own research programs,
other outreach programs, and national programs.
5. Ensure that our materials are evaluated under
different regional conditions and the information
is used in our selection to increase the usefulness
of our products to our partners.
6. Ensure that partners are aware of our products
and services and evaluate and use them.
7. Organize training courses on regionally
important issues.
8. Work directly with partners to identify superior
technologies, produce and distribute seed, and
promote relevant technologies.
9. Foster collaboration among national programs in
their region and facilitate the exchange of
information, experiences, and technologies.
Strengthen ties among public institutions, private
enterprise, and non-governmental organizations
involved in maize research and production to
make technology development and adoption
more efficient.

Outreach scientists spend now significantly more time
on development work. They are participating in
thousands of on-farm trials that address issues of soil
fertility management, Striga control and Striga
tolerance breeding, drought (especially in Africa), and
soil acidity (especially in South America). We recently
started a project in Kenya and Uganda to establish
sustainable seed production systems for resource-poor
farmers in areas where there are no alternate
suppliers. The project involves all types of partners
and is funded by the Rockefeller Foundation.

42
Maize Research Highlights 19992000

The CIMMYT Maize Program in 2000

Revitalized and Pro-Partner International Testing.
Wer recognized that international testing provides us
notonly with information to enhance the efficiency of
our research program but also an excellent vehicle for
showcasing and distributing our germplasm. As such,
itis cr ucial to our success, so:
* We now ship more trials and germplasm than ever.
* All our trials are now centrally announced, so partners
have access to all CIMMYT germplasm, regardless of
whether it was developed at headquarters or in
outreach.
* We include entries from other sites in trials
originatingfr om a given site.
* We have put germplasm and trial announcements
on-line.
* Time for returning results to partners has gone down
from 21 to 3 days. And during 1998-2000 we cleared a
backlog of six international testing reports (those for
1994-98, and a 1996 special report).
* We implemented a "key sites" approach for testing
germplasm where the data will be used primarily for
breeding. The objectives are to expose this germplasm
to different types of environments, especially stresses,
under which it will eventually be grown, and to use
the information in selection. Most of these sites are our
own outreach sites but occasionally they are operated
by partners.
* Historical international testing data back to 1974 are
now available on CD-ROM.
* All CIMMYT Maize Program scientists and many
partnersar e using our Fieldbook program for trial
design and pedigree and inventory management.

Collaboration with the Economics Program and the
NRG and ABC. We continue to work with the NRG on
natural resource issues. In addition, we and partners
have found particular value in the NRG's geographic
information system (CIS) products, which help improve
targeting and increase spillover benefits from our
outputs and services. In the latter regard, we have
worked recently with the NRG to refine maize mega
environment definitions," and have contributed to
development, promotion, and training activities for the
African Maize Atlas and several Country Almanacs,
including one on Nepal.

We have increased our collaboration with the
Economics Program in impacts assessment and other
areas. The study on Maize Program impacts in Latin
America came out in 1999; those on Africa and Asia
will be out this year. Another exciting area of
collaboration is research priority setting. We are also
working with CIMMYT economists on food vs. feed
issues in Asia. Maize scientists interact with
economists in regional programs on policy, adoption,
and other issues. We are working with them on
participatory breeding and farmer decision making,
especially in Mexico and sub-Saharan Africa. Finally,
the Economics Program completed a major study, with
help from Maize Program staff, comparing the costs of
DNA marker assisted selection and conventional
breeding (Dreher, K., and M. Morris. 2000. A Close
Look at Biotech Breeding Costs: The Details Make a
Difference. Available at: www.cimmyt.org/
whatiscimmyt/AR99_2000/future/a close/
a close.htm.)

Collaboration with ABC staff in the use of molecular
markers for QPM and breeding for resistance to maize
streak virus is now routine. We are working to see if
molecular markers will work for quantitative and
more complicated traits such as drought. A Maize
Program scientist is coordinator of the Insect Resistant
Maize for Africa project (IRMA), an effort to develop
insect resistant maize for African farmers through
conventional and biotechnology applications. Maize
staff are also participating in a drought tolerance
genomics project, as well as in the fingerprinting of
key CIMMYT maize germplasm. The Program has
followed progress in research at a CIMMYT on
apomixis. Perhaps the 2000 Plant Breeding Review
panel of TAC best summarized Program collaboration
with the ABC: "Progress in moving biotechnology
intomaize br eeding programs is on the right track,
and it is expected that in the next years it will
provesuccessful."

Collaboration with our partners. We are working
with many more partners now. Increases in the
number of trial and seed shipments clearly indicates
that collaboration has increased significantly with

1 Hartkamp, A.D., J.W White, A. Rodriguez Aguilar, M. Banziger, G. Srinivasan, G. Granados, and J. Crossa. 2000. Maize Production Environments
Revisited: A GIS-based Approach. Mexico, D.F.: CIMMYT.

43
Maize Research Highlights 1999 2000

public and private partners. Advanced research
institutes with which we share research activities
include Iowa State University, the University of
Wisconsin, the University of Hannover, the
University of Piracicaba, the University of Guelph.
We are working more closely with a range of non
governmental organizations in Africa, Nepal, and
Bangladesh, as well as promoting collaboration
among NGOs themselves.

Work with the private sector has increased
significantly, and we continue to seek ways to
enhance this collaboration, especially with small
national and regional companies. Private companies
now comprise the number-one user of CIMMYT
maize germplasm in Latin America and use of our
materials by private companies has increased in Asia
and Africa.

Regarding stronger national programs, we
participate in 11 collaborative research projects in
which we leverage resources of such organizations.
The Empresa Brasileira de Pesquisa Agropecuaria
(EMBRAPA) is our major partner in soil acidity
research in South America. We have benefited from
support from India, Brazil, and China in training.
Nonetheless, we clearly need to do more.

Conclusion

When we reflect back on where we were a few years
ago, there is convincing evidence of solid progress in
meeting the challenges the Program faced. A key
component for continued success will be obtaining
secure funding for the activities described in this
publication and the other important work the Program
conducts. In 2001 Program staff will actively seek
support for efforts such as the Africa Maize Stress
project, work to disseminate quality protein maize, and
sustainable seed production systems for small-scale
farmers in Africa, to name a few. This will involve
renewing relationships with traditional donors and
helping them make the case to their constituencies for
continued investment in agricultural research.
However, we will also try to identify and bring on
board new contributors from categories such as
philanthropic foundations and the private sector. Given
the challenges in today's funding environment, we need
to convey to responsible individuals in these and other
agencies a clear impression of the circumstances faced
today by small-scale, resource-poor maize farmersin
developing countries. This in turn must be followed up
with effective proposals and other information about
ways we can work together toward shared goals, in
benefit of developing country farmers and consumers

44
Maize Research Highlights 19992000

Maize Program Staff*

Shivaji Pandey (India), Director, s.pandey@cgiar.org
Ganesan Srinivasan (India), Associate Director, Senior
Scientist, Leader, Subtropical Maize/Head, International
Testing Unit, g.srinivasan@cgiar.org
Marianne Banziger (Switzerland), Senior Scientist,
Physiologist (based in Zimbabwe), m.banziger@cgiar.org
David Beck (USA), Senior Scientist, Leader, Highland Maize,
d.beck@cgiar.org
David Bergvinson (Canada), Senior Scientist, Entomologist,
d.bergvinson@cgiar.org
Jorge Bolafos (Nicaragua), Principal Scientist, Agronomist/
Physiologist, j.bolanos@cgiar.org
Hugo Cordova (El Salvador), Principal Scientist, Breeder/
Leader of Tropical Maize, h.cordova@cgiar.org
Carlos de Leon G. (Mexico), Principal Scientist, Pathologist/
Breeder/Liaison Officer (based in Colombia),
c.deleon@cgiar.org
Alpha 0. Diallo (Guinea), Principal Scientist, Breeder/
Liaison Officer (based in Kenya), a.diallo@cgiar.org
Dennis Friesen (Canada), Senior Scientist, Agronomist (based
in Kenya), d.friesen@cgiar.org
Fernando Gonzalez (Mexico), Senior Scientist, Breeder
(based in India), f.gonzalez@cgiar.org
Daniel Jeffers (USA), Senior Scientist, Pathologist,
d.jeffers@cgiar.org
Fred Kanampiu (Kenya), Associate Scientist, Agronomist
(based in Kenya), f.kanampiu@africaonline.co.ke
Duncan Kirubi (Kenya), Associate Scientist, Breeder,
d.kirubi@cgiar.org
Stephen Mugo (Kenya), Associate Scientist, Breeder (based in
Kenya), s.mugo@cgiar.org
Luis Narro (Peru), Scientist, Breeder (based in Colombia),
1.narro@cgiar.org
Marcelo E. Perez (Mexico), Program Administrator,
meperez@cimmyt.exch.cgiar.org
Kevin V. Pixley (USA), Senior Scientist, Breeder/Liaison
Officer (based in Zimbabwe), k.pixley@cgiar.org

Joel K. Ransom (USA), Senior Scientist, Agronomist (based in
Nepal), j.ransom@cgiar.org
Efr6n Rodriguez (Mexico), Head, Program based User
Support, e.rodriguez@cgiar.org
Suketoshi Taba (Japan), Principal Scientist, Head, Maize
Germplasm Bank, s.taba@cgiar.org
Surinder K. Vasal (India), Distinguished Scientist,
s.vasal@cgiar.org
Bindiganavile Vivek (India), Scientist, Breeder (based in
Zimbabwe), b.vivek@cgiar.org
Stephen Waddington (UK), Principal Scientist, Agronomist/
NRG Associate (based in Zimbabwe),
s.waddington@cgiar.org

Adjunct Scientists
Miguel Barandiaran (Peru), Breeder (based in Peru),
m.barandiaran@cgiar.org
Salvador Castellanos (Guatemala), Breeder (based in
Guatemala), s.castellanos@cgiar.org
Neeranjan Rajbhandari (Nepal), Agronomist (based in
Nepal), cimmyt-nepal@cgiar.org
Strafford Twumasi-Afriyie (Ghana), Breeder (based in
Ethiopia), s.twumasi@cgiar.org

Pre- and Postdoctoral Fellows
Julien de Meyer (Switzerland), Crop Scientist (based in
Zimbabwe), j.demeyer@cgiar.org
Carlos Urrea (Colombia), Breeder, c.urrea@cgiar.org
Narciso Vergara (Mexico), Breeder, n.vergara@cgiar.org

Consultants/Research Affiliates
Gonzalo Granados R. (Mexico), Training Consultant,
g.granados@cgiar.org
Mick S. Mwala (Zambia), Breeder, based in Zambia,
cimmyt-zimbabwe@cgiar.org
Mthakati A.R. Phiri (Malawi), Socioeconomist, based in
Malawi, cimmyt-zimbabwe @cgiar.org

* As of August 2001.

45
Maize Research Highlights 19992000

Maize Program Publications 1999-2000

Monographs

Banziger, M.; Edmeades, G.O.; Beck, D.L.; Bell6n, M.R. 2000.
Breeding for drought and nitrogen stress tolerance in maize: From
theory to practice. Mexico, DF (Mexico): CIMMYT. 68 p.
Banziger, M.; Pixley K.V; Vivek, B.; Zambezi, B.T. 2000.
Characterization of elite maize germplasm grown in Eastern and
Southern Africa -Results of the 1999 regional trials conducted
by CIMMYT and the Maize and Wheat Improvement Research
Network for SADC (MWIRNET) Harare (Zimbabwe): CIMMYT.
43 p.
Banziger, M.; Pixley K.V; Zambezi, B.T 1999. Drought and N stress
tolerance and maize germplasm grown in the SADC region:
Results of the 1998 regional trials conducted by CIMMYT and the
Maize and Wheat Improvement Research Network for SADC
(MWIRNET) Harare (Zimbabwe): CIMMYT. 22 p.
Banziger, M.; Barreto, H.J. 1999. Manual de usuario para fieldbook
5.1/7.1 y Alfa. Mexico, DF (Mexico): CIMMYT. 48 p. Includes 2
diskettes (3.5).
Banziger, M.; Barreto, H.J. 1999. A user's manual for fieldbook 5.1/
7.1 and alpha. Mexico, DF (Mexico): CIMMYT. 95 p. Includes 2
diskettes 3.5.
Bell6n, M.R.; Gambara, P. Gatsi, T; Machemedze, T; Maminimini,
0.; Waddington, S.R. 1999. Farmers' taxonomies as a participatory
diagnostic tool: Soil fertility management in Chihota, Zimbabwe.
Harare (Zimbabwe): CIMMYT. 17 p. Series: Soil Fertility Network
for Maize-Based Cropping Systems in Malawi and Zimbabwe
Network Research Results Working Paper. No. 4.
Bell6n, M.R.; Gambara, P. Gatsi, T; Machemedze, T.E.; Maminimini,
0.; Waddington, S.R. 1999. Farmers' taxonomies as a participatory
diagnostic tool: Soil fertility management in Chihota, Zimbabwe.
Mexico, DF (Mexico): CIMMYT. 18 p. Series: CIMMYT Economics
Working Paper. No. 99-13.
Bell6n, M.R.; Smale, M.; Aguirre, A.; Taba, S.; Arag6n, F.; Diaz, J.;
Castro Garcia, H. 2000. Identifying appropriate germplasm for
participatory breeding: An example from the Central Valleys of
Oaxaca, Mexico. Mexico, DF (Mexico): CIMMYT. v, 14 p. Series:
CIMMYT Economics Working Paper. No. 00 03.
Burgueflo, J.; Cadena, A.; Crossa, J.; Banziger, M.; Gilmour, A.R.;
Cullis, B. 2000. User's guide for spatial analysis of field variety
trials using ASREML. Mexico, DF (Mexico): CIMMYT. iv, 54 p.
Hartkamp, A.D.; White, J.W.; Rodriguez A.; Banziger, M.;
Srinivasan, G.; Granados, G.; Crossa, J. 2000. Maize Production
Environments Revisited: A GIS-based approach. Mexico, DF
(Mexico): CIMMYT. 33 p.
Heisey P.W.; Edmeades, G.O. 1999. CIMMYT 1997/98 world maize
facts and trends -Maize production in drought-stressed
environments: Technical options and research resource allocation.
Mexico, DF (Mexico): CIMMYT. 72 p. Series: CIMMYT World
Maize Facts and Trends.

Maize Program. 1999. CIMMYT International Maize Testing
Program: 1995 final report. Mexico, DF (Mexico): CIMMYT. 367 p.
Series: CIMMYT Maize International Testing Program.
Maize Program. 1999. CIMMYT International Maize Testing
Program: 1996 final report. Mexico, DF (Mexico): CIMMYT. 298 p.
Series: CIMMYT Maize International Testing Program.
Maize Program. 2000. CIMMYT International Maize Testing
Program -1996 special report: Drought and Low-Nitrogen
Tolerance Network Trials. Mexico, DF (Mexico): CIMMYT. 272 p.
Series: CIMMYT Maize International Testing Program.
Maize Program. 1999. CIMMYT International Maize Testing
Program: 1997 final report. Mexico, DF (Mexico): CIMMYT. 331 p.
Series: CIMMYT Maize International Testing Program.
Maize Program. 2000. CIMMYT International Maize Testing
Program: 1998 final report. Mexico, DF (Mexico): CIMMYT. 203 p.
Series: CIMMYT Maize International Testing Program.
Maize Program. 1999. A core subset of LAMP, from the Latin
American Maize Project, 1986-88. Mexico, DF (Mexico): CIMMYT.
1 CD-ROM.
Maize Program. 1999. Desarrollo, mantenimiento y multiplicaci6n
de semilla de variedades de polinizaci6n libre. Mexico, DF
(Mexico): CIMMYT. 11 p.
Maize Program. 1999. Managing trials and reporting data for
CIMMYT's International Maize Testing Program. Mexico, DF
(Mexico): CIMMYT. 20 p.
Maize Program. 1999. Manejo de los ensayos e informed de los datos
para el Programa de Ensayos Intemacionales de Maiz del
CIMMYT. Mexico, DF (Mexico): CIMMYT. 20 p.
Maize Program. 1999. Program de maiz del CIMMYT: Resefa de la
investigaci6n en 1997-98. Mexico, DF (Mexico): CIMMYT. 9 p.
Maize Program. 1999. Development, maintenance and seed
multiplication of open-pollinated maize varieties. Mexico, DF
(Mexico): CIMMYT. 11 p.
Morris, M.L.; Risopoulos, J.; Beck, D.L. 1999. Genetic change in
farmer-recycled maize seed: A review of the evidence. Mexico, DF
(Mexico): CIMMYT. 68 p. Series: CIMMYT Economics Working
Paper. No. 99 07.
Ngwira, P; Pixley K.V 2000. Eastern Africa regional maize nursery:
Project report for 1997 and 1998. Harare (Zimbabwe): CIMMYT.
45 p.
Pixley K.V, B.T. Zambezi, S.R. Waddington, H. Verkuijl, C.
Vaughan, S. Twumasi-Afriyie, W. Mwangi, J. De Meyer, M.
Mekuria, W. Legesse, D.C. Jewell, D. Friesen, A.O. Diallo and M.
Banziger, eds. 1999. Maize production technology for the future:
Challenges and opportunities. Proceedings of the Eastern and
Southern Africa Regional Maize Conference, 6; Addis Ababa
(Ethiopia); 21-25 Sep 1998. Addis Ababa (Ethiopia): CIMMYT /
EARO. xviii, 399 p.

46
Maize Research Highlights 19992000

Maize Program Publications

Taba, S. (ed.). 1999. Latin American maize germplasm
conservation: Core subset development and regeneration.
Proceedings of a Workshop; Mexico, DF (Mexico); 1-5 Jun 1998.
Mexico, DF (Mexico): CIMMYT. 62 p.
Waddington, S.R. 1999. Soil Fertility Network for Maize-Based
Cropping Systems in Malawi and Zimbabwe >:
Annual report for the Period 1 Oct 1998 to 30 Sep 1999. Harare
(Zimbabwe): CIMMYT. 23 p. Series: Soil Fertility Network for
Maize-Based Cropping Systems in Malawi and Zimbabwe.
Waddington, S.R.; Mekuria, M. 2000. Soil Fertility Network for
Maize-Based Farming Systems in Southern Africa >:
Annual report for the Period 1 Oct 1999 to 30 Sep 2000. Harare
(Zimbabwe): CIMMYT. 26 p. Series: Soil Fertility Management
and Policy Network for Maize-Based Farming Systems in
Southern Africa. Grant Number 1994-0020-0051.
Zambezi, B.T.; Mekuria, M.; Varughese, G.; Banziger, M.;
Manzvanzvike, TH. 1999. Maize and Wheat Improvement
Research Network for SADC (MWIRNET): 1998/99 annual
report. Harare (Zimbabwe): MWIRNET / CIMMYT. 58 p.

Journal articles, book chapters, and
presentations

Aragon, E; Taba, S.; Diaz, J.; Castro Garcia, H.; Hernandez Casillas, ].M.
2000. Mejoramiento participative del maiz Bolita de Oaxaca, Mexico.
In: Congreso Nacional de Fitogen6tica, 18. Memorias de las Notas
Cientificas; Irapuato, Guanajuato (Mexico); 15-20 Oct. 2000. Zavala
Garcia, R; Ortega Paczka, R.; Mejia Contreras, ].A.; Benitez Riquelme,
I.; Guill6n Andrade, H., (eds.). Montecillo, Tex. (Mexico); SOMEFI.
Aragon, E; Paredes Hernandez, E.; Ortega V, J.E; Taba, S.; Diaz, J.;
Castro Garcia, H.; Dillanes R., N. 2000. Diversidad gen6tica de la milpa
en la zona Mazateca, Cuicateca y Mixe de Oaxaca, Mexico. In:
Congress Nacional de Fitogen6tica, 18. Memorias de las Notas
Cientificas; Irapuato, Guanajuato (Mexico); 15-20 Oct 2000. Zavala
Garcia, R; Ortega Paczka, R.; Mejia Contreras, ].A.; Benitez Riquelme,
I.; Guill6n Andrade, H., (eds.). Montecillo, Tex. (Mexico); SOMEFI.
B&nziger, M.; Edmeades, G.O.; Lafitte, H.R. 1999. Selection for drought
tolerance increases maize yields across a range of nitrogen levels. Crop
Science 39 (4): 1035-1040.
B&nziger, M.; Damu, N.; Chisenga, M.; Mugabe, E 1999. Evaluating the
drought tolerance of some popular maize hybrids grown in Sub-Saharan
Africa. p. 61-63. In: Maize Production Technology for the Future:
Challenges and Opportunities. Proceedings of the Eastern and
Southern Africa Regional Maize Conference, 6; Addis Ababa
(Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis Ababa (Ethiopia);
CIMMYT/EARO.
Banziger, M.; Mugo, S.N.; Edmeades, G.O. 2000. Breeding for drought
tolerance in tropical maize: Conventional approaches and challenges to
molecular approaches. In: Molecular Approaches for the Genetic
Improvement of Cereals for Stable Production in Water-Limited
Environments. A Strategic Planning Workshop; El Batan, Texcoco
(Mexico); 21-25 Jun 1999. Ribaut, JM.; Poland, D. (eds.). Mexico,
DF (Mexico); CIMMYT.
Banziger, M. 2000. Recent progress on breeding for drought and low N
tolerance in maize for the SADC region. In: Program and Abstracts of
the Plant Breeding Symposium, 3; Harare, Zimbabwe; 13-16 Mar
2000.

B&nziger, M.; Long, ]. 2000. The potential for increasing the iron and zinc
density of maize through plant-breeding. Food and Nutrition Bulletin
21 (4) : 397 400.
Betran, F].; Beck, D.L.; Edmeades, G.O.; Ribaut, .M.; B&nziger, M.;
Sanchez, C. 1999. Genetic analysis of abiotic stress tolerance in tropical
maize hybrids. p. 69-71. In: Maize Production Technology for the
Future: Challenges and Opportunities. Proceedings of the Eastern
and Southern Africa Regional Maize Conference, 6; Addis Ababa
(Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis Ababa (Ethiopia);
CIMMYT/EARO.
Campo A., R.O.; araba N., ]. de D.; De Leon, C. 1999. Reconocimiento del
mildeo velloso del maiz en Tierralta, Cordoba, Colombia. ASCOLFI
Informa 25 (3) : 29-31.
Castarion, G.; offers, D.P; Hidalgo, H. 2000. Aptitud combinatoria de
lineas de maiz tropical con diferente capacidad para tolerar el
achaparramiento. Agronomia Mesoamericana 11 (1) : 77-81.
Cordova, H.S.; De Leon, C.; Srinivasan, G. 2000. Desarrollo y promocion
de nuevos hibridos de maiz de alta calidad de protein: Estrategias,
logros yperspectivas. In: Reuni6n Latinoamericana del Maiz, 18;
Memorias; Sete Lagoas, Minas Gerais, Brasil; 22-27 Ago 1999.
Brasilia (Brasil); EMBRAPA.
Crossa, J.; Vargas, M.; F .. -,. FA. van; iang, C.; Edmeades, G.O.;
Hoisington, D.A. 1999. Interpreting genotype X environment
interaction in tropical maize using linked molecular markers and
environmental covariables. Theoretical and Applied Genetics 99 (3
4) : 611-625.
De Leon, C. 2000. La mancha bandeada de la hoja de maiz (Rhizoctonia
solani Kunh) In: Curso Sobre Producci6n de Maiz, 6; Araure Edo.
Portuguesa, Venezuela; 2-13 Ago 1999. Portuguesa (Venezuela);
ASOPORTUGUESA /FONAIAP
De Leon, C.; Narro, L.; Ruiz, C.; Jeffers, D.P; Arias, M.P; Salazar, F 1999.
Avances en la seleccion de resistencia gen6tica al achaparramiento del
maiz. In: Memorias del Congreso Nacional de Fitopatologia 20;
Manizales, Colombia; 30 Jun -2 Jul 1999. Manizales, Colombia:;
ASCOLFI, Abstract only.
De Leon, C.; Narro, L.; Arias, M.P.; Salazar, F; Morales, F..; Geronimo, L.;
Machado, V; Parentoni, S.N.; Resende, I.; Reyes, S.; Galvez, M.;
Cabrera, S. 1999. Desarrollo de resistencia a plagas y enfermedades del
maiz en America del Sur -Un proyecto colaborativo. In: Reuni6n
Latinoamericana del Maiz, 18; Memorias; Sete Lagoas, Minas
Gerais, Brasil; 22-27 Ago 1999. Sete Lagoas (Brasil); CNPMS/
EMBRAPA.
De Leon, C.; Narro, L.; Ruiz, C.; Jeffers, D.P; Salazar, E; Arias, M.P 1999.
Avances en la seleccion de resistencia gen6tica al achaparramiento del
maiz. ASCOLFI Informa 25: 38-40.
Derera, J.; Pixley, K. V; Giga, D.P 1999. Inheritance of maize weevil
resistance in maize hybrids among maize lines from Southern Africa,
Mexico and CIMMYT Zimbabwe. In: Maize Production Technology
for the Future: Challenges and Opportunities. Proceedings of the
Eastern and Southern Africa Regional Maize Conference, 6; Addis
Ababa (Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis Ababa
(Ethiopia); CIMMYT/EARO.
Edmeades, G.O.; Bolanios, JA.; Elings, A.; Ribaut, .M.; Banziger, M.;
Westgate, M.E. 2000. The role and regulation of the anthesis-silking
interval in maize. In: Physiology and Modeling Kernel Set in
Maize. CSSA Special Publication No. 29. Madison, WI (USA);
CSSA.

47
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Edmeades, G.O.; Banziger, M.; Ribaut, J. M. 2000. Maize improvement for
drought limited environments. In: Physiological bases for maize
improvement., (Otegui, M. Slafer, G.A.). New York (USA); Food
Products Press.
Elings, A. 2000. Estimation of leaf area in tropical maize. Agronomy
Journal 92 (3) : 436-444.
Esilaba, A.O.; Reda, F; Ransom, J.K; Bayu, W; Woldewahid, G.;
Zemichael, B. 1999. Integrated nutrient management strategies for soil
fertility improvement and Striga control in Northern Ethiopia. p. 185
189. In: Maize Production Technology for the Future: Challenges
and Opportunities. Proceedings of the Eastern and Southern
Africa Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21
25 Sep 1998. CIMMYT EARO Addis Ababa (Ethiopia); CIMMYT/
EARO.
Esilaba, A.O.; Reda, F; Ransom, J.K; Bayu, W; Woldewahid, G.;
Zemichael, B. 2000. Integrated nutrient management strategies for soil
fertility improvement and Striga control on Northern Ethiopia. African
Crop Science Journal 8 (4) : 403-410. Internet address: http://
www.bdt.org.br/bioline/',l. r ...., ,,.', : ,,.. I'SN 1021-9730/
2000.
Esilaba, A.O.; Reda, F.; Ransom, J.K.; Woldewahid, G.; Bayu, W;
Zemichael, B. 1999. Potential for relay cropping and improved
fallows in soil fertility improvement and Striga control in
Northern Ethiopia. Soil Science Society of East Africa
Proceedings, 17; Uganda (Africa): SSSEA. 54-62. Kampala
(Uganda); SSSEA, 1999.
Feil, B.; Banziger, M. 1999. Beziehungen zwischen dem Kornertrag und
den Konzentrationen von Protein, Phosphor undKalium in den
Kornern von Sommerweizensorten. Pflanzenbauwissenschaften 3 (1)
: SI-18.
Figueroa Cardenas, JD.; Taba, S.; Diaz, J.; Santoyo, C.; Morales, S.E.
1999. Characterization of maize race bolita for tortilla yield and starch
properties. In: Latin American maize germplasm conservation:
Core subset development and regeneration. Taba, S., (ed.). Mexico,
DF (Mexico); CIMMYT.
Franco, J.; Crossa, J.; Villaseior, J.; Castillo, A.; Taba, S.; Eberhart, S.A.
1999. A two-stage, three-way method for classifying genetic resources in
multiple environments. Crop Science 39 (1) : 259-267.
Fritzsche Hoballah, M. E.; Turlings, T.; Bergvinson, D.J. 2000. Exploring
maize genotypes for chemical attributes that promote the effectiveness of
biological control agents. 1 p. In: Swiss Centre for International
Agriculture (ZIL): Annual Report 2000. Zurich (Switzerland);
Eidgenissische Technische Hochschule Ziirich, 2000.
Garcia Vazquez, M.A.; Marquez Sanchez, E; Ron Parra, J.; Beck, D.L.
2000. Correlacion de los parametros de estabilidad y la media de
rendimiento en hibridos de maiz resistentes a la sequoia. In: Congreso
Nacional de Fitogenetica, 18. Memorias de las Notas Cientificas;
Irapuato, Guanajuato (Mexico); 15-20 Oct 2000. Zavala Garcia, E;
Ortega Paczka, R.; Mejia Contreras, J.A.; Benitez Riquelme, I.; Guillen
Andrade, H (eds.). Montecillo, Tex. (Mexico); SOMEFI.
Giller, K.E.; Mpepereki, S.; Mapfumo, P; Kasasa, P.; Sakala, WD.;
Phombeya, H.; Itimu, O.A.; Cadisch, G.; Gilbert, R.A.; Waddington,
S.R. 2000. Putting legume N2-fixation to work in cropping systems of
Southern Africa. In: Nitrogen Fixation: From Molecules to Crop
Productivity. Pedrosa, F.O. et al.], (eds.). Dordrecht (Netherlands);
Kluwer Academic Publisher.

Gonzalez Ceniceros, F.; Vasal, S.K. 1999. Classes of seeds in hybrid
seed production. Paper presented at the Advanced Seed
Production Course in Maize; Hyderabad, India; 8-12 Mar 1999. 5
p.
Gonzalez Ceniceros, F.; Vasal, S.K. 1999. Some considerations in
seed production of conventional hybrids. Paper presented at the
Advanced Seed Production Course in Maize; Hyderabad, India;
8-12 Mar 1999. 4 p.
Granados, G. 2000. Maize insects. In: Tropical Maize Improvement
and Production. Paliwal, R.L.; Granados, G.; Lafitte, R.; Violic, A.D.;
Marathee, J.P Rome (Italy); FAO, Series: FAO Plant Production and
Protection Series. 28.
Granados, G.; Paliwal, R.L. 2000. Breeding for insect resistance. In:
Tropical Maize Improvement and Production. Paliwal, R.L.;
Granados, G.; Lafitte, R.; Violic, A.D.; Marathee, J.P Rome (Italy);
FAO, Series: FAO Plant Production and Protection Series. 28.
Granados, G. 2000. Integrated pest management. In: Tropical Maize
Improvement and Production. Paliwal, R.L.; Granados, G.; Lafitte,
R.; Violic, A.D.; Marathee, J.P Rome (Italy); FAO, Series: FAO Plant
Production and Protection Series. 28.
Granados, G. 2000. Post harvest management. In: Tropical Maize
Improvement and Production. Paliwal, R.L.; Granados, G.; Lafitte,
R.; Violic, A.D.; Marathee, J.P Rome (Italy); FAO, Series: FAO Plant
Production and Protection Series. 28.
Grimanelli, D.; Kanampiu, FK.; Odhiambo, G.D.; Okoth Mbogo, P.;
Hoisington, D.A. 2000. Identification of genes for tolerance to Striga in
maize using transposable elements. In: Breeding for Striga
Resistance in Cereals. Proceedings of a Workshop; Ibadan,
Nigeria; 18-20 Aug 1999. Haussmann, B.I.G.; Hess, D.E.; Koyama,
M.L.; Grivet, L.; Rattunde, H. W; Geiger, H.H. (eds.). Weikersheim
'i. .... "I1 Margraf Verlag, Abstract only.
Guta, A.; Wolde, L.; Keneni, G.; Abera, W; Tolessa, B.; Pixley, K. V;
Worku, M. 1999. Strategies for quality protein maize (QPM) breeding
and dissemination in Ethiopia. p. 42-46. In: Maize Production
Technology for the Future: Challenges and Opportunities.
Proceedings of the Eastern and Southern Africa Regional Maize
Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep 1998. CIMMYT;
EARO Addis Ababa (Ethiopia); CIMMYT/EARO.
Hodson, D.P; Rodriguez, A.; White, J.W; Corbett, J.D.; O'Brien, R.F;
Banziger, M. 1999. An African maize research atlas. p. 96-99. In:
Maize Production Technology for the Future: Challenges and
Opportunities. Proceedings of the Eastern and Southern Africa
Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep
1998. CIMMYT EARO Addis Ababa (Ethiopia); CIMMYT/EARO.
Jiang, C.; Edmeades, G.O.; Armstead, I.; Lafitte, H.R.; Hayward, M.;
Hoisington, D.A. 1999. Genetic analysis of adaptation differences
between highland and lowland tropical maize using molecular markers.
Theoretical and Applied Genetics 99 (7 8) : 1106-1119.
Kamau, G.M.; Ransom, J.K.; Saha, H.M. 1999. Maize-cowpea rotation for
weed management and improvement of soil fertility on a sandy soil in
coastal Kenya. p. 223-225. In: Maize Production Technology for the
Future: Challenges and Opportunities. Proceedings of the
Eastern and Southern Africa Regional Maize Conference, 6;
Addis Ababa (Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis
Ababa (Ethiopia); CIMMYT/EARO.

48
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Maize Program Publications

Kanampiu, EK.; Ransom, JK.; Gressel, J. 2000. Utilization of herbicide
resistance to combat Striga in maize. In: Breeding for Striga
Resistance in Cereals. Proceedings of a Workshop; Ibadan,
Nigeria; 18-20 Aug 1999. Haussmann, B.I.G.; Hess, D.E.; Koyama,
M.L.; Grivet, L.; Rattunde, H.W.; Geiger, H.H., (eds.). Weikersheim
I"-. ,1,,11 i' Margraf Verlag.
Kanampiu, FK.; Ransom, JK.; Gressel, J. 1999. Advantages of seed
primed imazapyr for Striga hermonthica control on maize bearing
target-site resistances, p. 172-179. In: Maize Production
Technology for the Future: Challenges and Opportunities.
Proceedings of the Eastern and Southern Africa Regional Maize
Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep 1998.
CIMMYT; EARO Addis Ababa (Ethiopia); CIMMYT/EARO.
Khairallah, MM.; Bergvinson, D.].; Bohn, M.; Groh, S.; Jewell, D.C.;
Jiang, C.; Melchinger, A.E.; Mihm, ].A.; Hoisington, D.A. 1999. QTL
mapping of insect resistance and associated traits in tropical maize. In:
Plant Genomics, Structural, Functional and Applied Aspects.
Gatersleben Research Conference, 4; Abstracts; Gatersleben
(Germany); 17-21 Jun 1999. Gatersleben i" .....,11 IPK
Gatersleben, Abstract only.
Kling, ].G.; Fajemisin, ].M.; Badu-Apraku, B.; Diallo, A.O.; Menkir, A.;
Melake-Berhan, A. 2000. Striga resistance breeding in maize. In:
Breeding for Striga Resistance in Cereals. Proceedings of a
Workshop; Ibadan, Nigeria; 18-20 Aug 1999. Haussmann, B.I.G.;
Hess, D.E.; Koyama, ML.; Grivet, L.; Rattunde, H.W.; Geiger, H.H. ,
(eds.). Weikersheim (Germany); Margraf Verlag.
Manda, TH.E.; Banziger M.; Stamp, P; Richter, W 2000. Relationship
between tolerance to drought, low soil nitrogen and soil acidity in
tropical maize genotypes. 1 p. In: Swiss Centre for International
Agriculture (ZIL): Annual Report 2000. Zurich (Switzerland);
Eidgenissische Technische Hochschule Zirich, 2000.
Mauricio S., R.A.; Figueroa Cardenas, ].D.; Mendoza, G.A.; Gaytan,
M.M.; Taba, S. 2000. Uso final de razas mexicanas de maiz, por medio
de sus propiedades fisicoquimicas, termicas y electricas. In: Congreso
Nacional de Fitogenetica, 18. Memorias de las Notas Cientificas;
Irapuato, Guanajuato (Mexico); 15-20 Oct. 2000. Zavala Garcia, E;
Ortega Paczka, R.; Mejia Contreras, J.A.; Benitez Riquelme, I;
Guillen Andrade, H., (eds.). Montecillo, Tex. (Mexico); SOMEFI.
Muasya, W.N.P; Diallo, A.O. 1999. Evaluation of maize hybrids and
inbred lines for resistance to Striga. p. 164-167. In: Maize
Production Technology for the Future: Challenges and
Opportunities. Proceedings of the Eastern and Southern Africa
Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21 25
Sep 1998. CIMMYT; EARO Addis Ababa (Ethiopia); CIMMYT/
EARO.
Mugo, S.N.; Binziger, M.; Edmeades, G.O. 2000. Prospects of using
ABA in selection for drought tolerance in cereal crops. In: Molecular
Approaches for the Genetic Improvement of Cereals for Stable
Production in Water-Limited Environments. A Strategic
Planning Workshop; El Batan, Texcoco (Mexico); 21-25 Jun 1999.
Ribaut, .M.; Poland, D., (eds.). Mexico, DF (Mexico); CIMMYT.
Murata, M.; Waddington, S.R.; Murwira, H.K. 2000. Rehabilitation of
degraded infertile sandy soils using annual green manures in
Zimbabwe. Target (21) : 45.

Mushayi, P.T.; Waddington, S.R.; Chiduza, C. 1999. Low efficiency of
nitrogen use by maize on smallholder farms in sub-humid
Zimbabwe. p. 278-281. In: Maize Production Technology for the
Future: Challenges and Opportunities. Proceedings of the Eastern
and Southern Africa Regional Maize Conference, 6; Addis Ababa
(Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis Ababa
(Ethiopia); CIMMYT / EARO.
Narro, L.; Pandey S.; Leon, L.A.; Perez, J.C.; Salazar, F. 1999.
Investigaci6n en variedades de maiz para suelos acidos. In:
Sistemas Agropastoriles en Sabanas Tropicales de America Latina.
Guimaraes, E.P (ed.). Cali (Colombia); CIAT.
Narro, L.; De Leon, C.; Salazar, F.; Arias, M.P 1999. Program de
Maiz del CIMMYT para tolerancia a suelos acidos. In: Reuni6n
Latinoamericana del Maiz, 18; Memorias; Sete Lagoas, Minas
Gerais, Brasil; 22-27 Ago 1999. Sete Lagoas (Brasil); CNPMS /
EMBRAPA.
Narro, L.A. 2000. Mejoramiento y selecci6n de tolerancia contra
factors abi6ticos. In: Curso Internacional sobre Desarrollo de
Hibridos y Producci6n de Semilla de Maiz, 1. Portuguesa
(Venezuela); ASOPORTUGUESA, Draft version.
Narro, L.A.; Perez, J.C.; Pandey S.; Crossa, J.; Salazar, F.; Arias, M.P.;
Franco, J. 2000. Diallel and triallel analysis in an acid soil tolerant
maize (Zea mays L.) population. Maydica 45 (4) : 301-308.
Ngwira, P.; Pixley K.V; De Vries, J.; Kanaventi, C.M. 1999. Major
maize disease problems and farmer's varietal preferences in
Malawi. p. 113-116. In: Maize Production Technology for the
Future: Challenges and Opportunities. Proceedings of the Eastern
and Southern Africa Regional Maize Conference, 6; Addis Ababa
(Ethiopia); 21-25 Sep 1998. CIMMYT; EARO Addis Ababa
(Ethiopia); CIMMYT / EARO.
Nourse, S.M.; Elings, A.; Brewbaker, J.L. 1999. Quantitative trait loci
associated with lime-induced chlorosis in recombinant inbred
lines of maize. Maydica 44 (4) : 293-299.
Odongo, O.M.; Ransom, J.K.; Devries, J. 2000. Screening of Teosinte
derived maize lines for resistance to Striga hermonthica in
Western Kenya. In: Breeding for Striga Resistance in Cereals.
Proceedings of a Workshop; Ibadan, Nigeria; 18-20 Aug 1999.
Haussmann, B.I.G.; Hess, D.E.; Koyama, M.L.; Grivet, L.;
Rattunde, H.W. Geiger, H.H., (eds.). Weikersheim (Germany);
Margraf Verlag.
Odongo, O.M.; Abayo, G.O.; Ransom, J.K.; Ojiem, J.; De Vries, J.;
Kling, J. 1999. Striga hermonthica control strategy through maize
variety resistance/tolerance in Western Kenya. p. 161-163. In:
Maize Production Technology for the Future: Challenges and
Opportunities. Proceedings of the Eastern and Southern Africa
Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep
1998. CIMMYT; EARO Addis Ababa (Ethiopia); CIMMYT /
EARO.
Ojiem, J.O.; Ransom, J.K.; Odongo, O.M.; Okwuosa, E.A. 1999.
Agronomic and chemical characterization of potential green
manure species in Western Kenya. p. 210-213. In: Maize
Production Technology for the Future: Challenges and
Opportunities. Proceedings of the Eastern and Southern Africa
Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep
1998. CIMMYT; EARO Addis Ababa (Ethiopia); CIMMYT /
EARO.

49
Maize Research Highlights 19992000

Oswald, A.; Ransom, J.K.; Abayo, G.O.; Kroschel, J.; Sauerborn, J.
1999. Intercropping: An option for Striga control. In: Advances in
Parasitic Weed Control at On-farm Level vol. 1. Joint Action to
Control Striga in Africa. Kroschel, J.; Mercer-Quarshie, H.;
Sauerborn, J. (eds.). Weikersheim (Germany); Margraf Verlag.
Oswald, A.; Ransom, J.K.; Kroschel, J.; Sauerborn, J. 1999.
Suppression of Striga on maize with intercrops. p. 168-171. In:
Maize Production Technology for the Future: Challenges and
Opportunities. Proceedings of the Eastern and Southern Africa
Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep
1998. CIMMYT; EARO Addis Ababa (Ethiopia); CIMMYT /
EARO.
Pardey PG.; Koo, B.; Wright, B.D.; Dusen, M.E. van; Skovmand, B.;
Taba, S. 1999. Costing the ex-situ conservation of genetic
resources: Maize and wheat at CIMMYT. Washington, DC (USA):
IFPRI / CIMMYT. iii, 103 p. Series: EPTD Discussion Paper. No.
52.
Perez Brito, D.; Jeffers, D.; Gonzalez de Leon, D.; Khairallah, M.;
Cortes C., M.; Velazquez C., G.; Azpiroz, S.; Srinivasan, G. 2001.
QTL Mapping of Fusarium moniliforme ear rot resistance in
highland maize, Mexico. Montecillo, Tex. (Mexico): CP p. 181-196.
Agrociencia 35 (2) : 181-196.
Pernet, A.; Hoisington, D.A.; Dintinger, J.; Jewell, D.C.; Jiang, C.;
Khairallah, M.M.; Letourmy P. Marchand, J.L.; Glaszmann, J.C.;
Gonzalez de Leon, D. 1999. Genetic mapping of maize streak
virus resistance from the Mascarene source. II: Resistance in line
CIRAD390 and stability across germplasm. Theoretical and
Applied Genetics 99 (3-4) : 540 533.
Pernet, A.; Hoisington, D.A.; Franco, J.; Isnard, M.; Jewell, D.C.;
Jiang, C.; Marchand, J.L.; Reynaud, B.; Glaszmann, J.C.; Gonzalez
de Leon, D. 1999. Genetic mapping of maize streak virus
resistance from the Mascarene source. I: Resistance in line D211
and stability against different virus clones. Theoretical and
Applied Genetics 99 (3-4) : 524-539.
Rajbhandari, N.P 2000. Declining soil fertility constrains maize
production in the hills -a review of recent surveys of farmers
practices, perceptions and conceptualizing a basis for proper
targeting of maize research in the hills. In: Improved soil fertility
management for sustainable maize production. Proceedings of a
Working Group Meeting of the Hill Maize Research Project;
Kathmandu (Nepal); 16-18 Aug. 2000. Kathmandu (Nepal);
NARC / CIMMYT.
Ramirez V, S.; Diaz S., E.; Diaz, J.; Taba, S. 2000. Colecci6n,
evaluaci6n y uso de maices criollos en los valles altos de
Chihuahua, Mexico. In: Congreso Nacional de Fitogenetica, 18.
Memorias de las Notas Cientificas; Irapuato, Guanajuato
(Mexico); 15-20 Oct 2000. Zavala Garcia, F.; Ortega Paczka, R.;
Mejia Contreras, J.A.; Benitez Riquelme, I.; Guillen Andrade, H. ,
(eds.). Montecillo, Tex. (Mexico); SOMEFI.
Ransom, J.K. 1999. The status quo of Striga control: Cultural,
chemical and integrated aspects. In: Advances in Parasitic Weed
Control at On-farm Level vol. 1. Joint Action to Control Striga in
Africa. Kroschel, J.; Mercer-Quarshie, H.; Sauerborn, J. (eds.).
Weikersheim (Germany); Margraf Verlag.
Ransom, J.K. 2000. Long-term approaches for the control of Striga in
cereals: field management options. Crop Protection 19 (8-10) : 759
763.

Ransom, J.K. 2000. Monitoring nutrient cycling can help identify
researchable soil fertility priorities. In: Improved soil fertility
management for sustainable maize production. Proceedings of a
Working Group Meeting of the Hill Maize Research Project;
Kathmandu (Nepal); 16-18 Aug. 2000. Kathmandu (Nepal);
NARC / CIMMYT.
Ribaut, J.M.; Edmeades, G.O.; Betran, EJ.; Jiang, C.; Banziger, M.
2000. Marker-assisted selection for improving drought tolerance
in tropical maize. In: Genetic Improvement of Rice for Water
Limited Environments. Ito, 0.; O'Toole, J.; Hardy B. (eds.).
Manila (Philippines); IRRI.
Ribaut, J.M.; Betran, F.J. 1999. Single large-scale marker-assisted
selection (SLS-MAS) Molecular Breeding 5 (6) : 531-541.
Ribaut, J.M.; Edmeades, G.O.; Hoisington, D.A. 2000. The genetic
basis of drought tolerance in maize and options for improvement
via marker-assisted selection. In: Plant Genetic Engineering:
Towards the Third Millennium: Where Chemistry Meets Ecology;
Jerusalem, Israel; 25-30 Jul 1999. Arencibia, A.D. (ed.). Elsevier.
Ribaut, J.M.; Edmeades, G.O.; Khairallah, M.M.; Hoisington, D.A.
2000. Mapping and marker-assisted selection for drought
tolerance in tropical maize. In: Memorias del Simposium
Intemacional >;
Monterrey (Mexico); 10 12 Ago 1999. Monterrey NL (Mexico);
INIFAP / MIAC / UANL.
Ribaut, J.M.; Edmeades, G.O.; Perotti, E.; Hoisington, D.A. 2000.
QTL analyses, MAS results, and perspectives for drought
tolerance improvement in tropical maize. In: Molecular
Approaches for the Genetic Improvement of Cereals for Stable
Production in Water-Limited Environments. A Strategic Planning
Workshop; El Batan, Texcoco (Mexico); 21-25 Jun 1999. Ribaut,
J.M.; Poland, D. (eds.). Mexico, DF (Mexico); CIMMYT.
Rodriguez Herrera, S.; Santana Rodriguez, J.; Cordova, H.S.; Vergara
A., N.; Lozano del Rio, A.J.; Mendoza Elos, M.; Bolanos Juarez,
J.G. 2000. Caracteres de importancia para el fitomejoramiento del
maiz para 1. i.1 In: Congreso Nacional de Fitogenetica, 18.
Memorias de las Notas Cientificas; Irapuato, Guanajuato
(Mexico); 15-20 Oct. 2000. Zavala Garcia, F; Ortega Paczka, R.;
Mejia Contreras, J.A.; Benitez Riquelme, I.; Guillen Andrade, H. ,
(eds.). Montecillo, Tex. (Mexico); SOMEFI.
San Vicente, FM.; Vasal, S.K.; McLean, S.D.; Ramanujam, S.K.;
Barandiaran, M. 1999. Comportamiento de lines tropicales
precoces de maiz en condiciones de sequia. Agronomia Tropical
49 (2) : 135-154.
Shamudzarira, Z.; Robertson, M.J.; Mushayi, P.T. Keating, B.;
Waddington, S.R.; Chiduza, C.; Grace, P. 1999. Simulating N
fertilizer response in low-input farming systems I. Fertiliser
recovery and crop response. In: Symposium on Cropping Systems>> Barcelona (Spain); European Society of
Agronomy
Sierra Macias, M.; Cano, 0.; Turrent Fernandez, A.; Cordova, H.S.;
Rodriguez Montalvo, F.A.; Sandoval Rinc6n, A.; Espinosa
Calderon, A.; Gonzalez Corona, M.; Aveldano Salazar, R. 2000.
Hibridos y variedades de maiz con alta calidad de protein para
el tr6pico mexicano. In: Reunion Latinoamericana del Maiz, 18;
Memorias; Sete Lagoas, Minas Gerais, Brasil; 22-27 Ago 1999.
Brasilia (Brasil); EMBRAPA.
Srinivasan, G.; Brewbaker, J.L. 1999. Genetic analysis of hybrids
between maize and perennial Teosinte. II: Ear traits. Maydica 44
(4): 371-384.

50
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Maize Program Publications

Srinivasan, G. 1999. James L. Brewbaker: A distinguished maize and
tree breeder and an inspiring teacher: An appreciation. Maydica
44 (4) : 263-270.
Srinivasan, G.; Brewbaker, J.L. 1999. Genetic analysis of hybrids
between maize and perennial Teosinte I: Morphological traits.
Maydica 44 (4) : 353-369.
Taba, S.; Eberhart, S.A.; Listman, G.M. 1999. Latin American maize
genetic resources: Conservation, regeneration, and forming core
subsets. Diversity 15 (2) : 16-17.
Taba, S.; Eberhart, S.A. 1999. The status of latin American maize
germplasm conservation. In: Latin American maize germplasm
conservation: Core subset development and regeneration. Taba, S.
(ed.). Mexico, DF (Mexico); CIMMYT.
Taba, S.; Diaz, J.; Franco, J.; Crossa, J.; Eberhart, S.A. 1999. A core
subset of LAMP. In: Latin American maize germplasm
conservation: Core subset development and regeneration. Taba, S.
(ed.). Mexico, DF (Mexico); CIMMYT.
Tadeo Robledo, M.; Espinosa Calderon, A.; Beck, D.L.; Torres, J.L.;
Hernandez, E. 2000. Rendimiento de semilla de cruzas simples de
maiz androesteriles y f6rtiles progenitoras de hibridos trilineales.
In: Congreso Nacional de Fitogenetica, 18. Memorias de las Notas
Cientificas; Irapuato, Guanajuato (Mexico); 15-20 Oct 2000. Zavala
Garcia, F.; Ortega Paczka, R.; Mejia Contreras, J.A.; Benitez
Riquelme, I.; Guillen Andrade, H. (eds.). Montecillo, Tex.
(Mexico): SOMEFI.
Tembo, E.; Pixley K.V. 1999. Heritability of resistance to grey leaf
spot in four maize populations. p. 37-41. In: Maize Production
Technology for the Future: Challenges and Opportunities.
Proceedings of the Eastern and Southern Africa Regional Maize
Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep 1998. CIMMYT;
EARO Addis Ababa (Ethiopia); CIMMYT / EARO.
Vasal, S.K.; Gonzalez Ceniceros, F. 1999. Maize reproductive system:
Exploiting, strengths and weaknesses in seed production
programs. Paper presented at the Advanced Seed Production
Course in Maize; Hyderabad, India; 8-12 Mar 1999. 5 p.
Vasal, S.K.; Gonzalez Ceniceros, F. 1999. Maize germplasm products
and their relevance. Paper presented at the Advanced Seed
Production Course in Maize; Hyderabad, India; 8-12 Mar 1999. 5
p.
Vasal, S.K.; Gonzalez Ceniceros, F. 1999. Non-conventional maize
hybrids and their seed production. Paper presented at the
Advanced Seed Production Course in Maize; Hyderabad, India;
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51
Maize Research Highlights 19992000

52
Maize Research Highlights 19992000

	Front Cover
	Table of Contents
	Foreword
	Stress-tolerant maize for farmers...
	Research on tropical highland...
	Increasing the productivity and...
	Quality protein maize : Improved...
	Storage pest resistance in...
	The CIMMYT maize program in...
	Maize program staff
	Maize program publications...

MILLISECOND	CLASS.METHOD	MESSAGE
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