Program, work planning week........................................................................................... 3
Priority setting and scaling innovations for IITA research-for-development
impacts. Manyong ....................................................................................................... 8
Ecofriendly integrated pest management: concept and implementation
at IITA. Neuenschwander ............................................................................................ 9
Plant genetic resources and biotechnology for germplasm enhancement of crops
grown by African farmers. Asiedu ............................................................................... 10
Crop improvement and new tools for managing genotype-by-environment interactions,
parental selection, and participatory breeding in Africa. Dixon .................................. 11
Integrated natural resources management–where we stand at IITA?................................. 13
Project A highlights. Ingelbrecht......................................................................................... 14
Cocoa genetics–the first step to understanding chocolate quality. Kolesnikova-Allen ........ 18
What cowpea genetics tell about germplasm improvement? Singh ................................... 19
Managing a puzzle through banana/plantain functional genomics. Moonan.................... 20
Project B highlights. Tamò ................................................................................................ 22
African root and tuber scale–a new threat for cassava in Africa. Hanna............................ 25
Biological control of the banana weevil in Africa. Nankinga ............................................. 26
Flying together–germiniviruses and whitefly. James Legg................................................... 27
Project C highlights. Gockowski......................................................................................... 28
Market-driven agriculture and commercialization in Africa. Abele.................................... 32
Rural livelihood and poverty mapping: contribution to R4D priority setting. Kormawa..... 33
Globalization, African agriculture, and the rural poor. Ferris ............................................ 34
Project D highlights. Whyte............................................................................................... 35
IPM on East African banana–coffee systems. Okech ......................................................... 38
Status of host plant resistance breeding to nematodes in Musa gerplasm. Dochez............ 39
Multiplication and distribution of superior planting materials–postharvest
intervention activities. Andrade................................................................................... 40
Marketing cost of cassava and sweetpotato in Southern Africa: the case of Malawi,
Tanzania, and Zambia. Mahungu ............................................................................... 43
Project E highlights. Tenkouano......................................................................................... 45
Legumes in the cropping systems of the humid forest margins. Nolte............................... 51
Improving yam planting materials and crop management. Shiwachi................................ 52
Managing resources in the Congo Basin. Robiglio............................................................. 53
Project F highlights. Singh................................................................................................. 54
Integrated control of Imperata and other weeds. Chikoye .................................................. 55
Managing Striga on cowpea and maize cropping systems. Emechebe ................................ 56
Matching crops and soils using integrated natural resources management
in the dry and moist savannas. Diels ........................................................................... 57
The functions of the contracts and grants office in IITA. Schöning .................................. 58
IITA Work Planning Week
4–10 Dec. 2003
Open Plenary Day 1: Thursday 4 December 2003
Morning Session Chairman: RDC Chairman Ortiz
8:30 am: Welcome by IITA Director General Hartmann
8:45 am: Greetings from Stakeholders, Partners, and Investors
9:15 am: RDC Councilor Manyong Priority Setting and Scaling Innovations for IITA
9:45 am: RDC Councilor Neuenschwander Ecofriendly IPM Management: Concept
and Implementation at IITA
10:15 am: Coffee Break
10:45 am: RDC Councilor Asiedu Plant Genetic Resources and Biotechnology for
Germplasm Enhancement of Crops Grown by African Farmers
11:15 am: RDC Councilor Dixon Crop Improvement and New Tools for Managing
Genotype-by-Environment Interactions, Parental Selection, and Participatory
Breeding in Africa
11:45 am: Working Group Convener Integrated Natural Resources Management–Where
We Stand at IITA
12:15 pm: General Discussion for morning session of first open plenary day
12:45 pm: Buffet Lunch
Afternoon Session Chairman: IITA Director General Hartmann
2:00 pm: Coordinator Ingelbrecht 2003 Highlights of Project A: Preserving and
Enhancing Germplasm and AgroBiodiversity with Conventional and
2:30 pm: Assoc. Scientist Kolesnikova-Allen Cocoa Genetics–The First Step to
Understanding Chocolate Quality
3:00 pm: Scientist Singh What Cowpea Genetics Tell about Germplasm Improvement
3:30 pm: Coffee Break
4:00 pm: Assoc. Scientist Moonan Managing A Puzzle Through Banana/Plantain
4:30 pm: General Discussion for Project A
5:00 pm: Adjourn
7:00 pm: Welcoming Cocktail at IITA Cappa Bar
Open Plenary Day 2: Friday 5 December 2003
Morning Session Chairman: RDC Councilor Designee Hughes
8:30 am: Coordinator Tamò 2003 Highlights of Project B: Developing Biologically-
based Pest, Disease and Weed Management Options, and Conserving
Biodiversity for Sustainable Agriculture
9:00 am: Scientist Hanna African Root and Tuber Scale–A New Threat for Cassava in
9:30 am: Visiting Scientist Nankinga Current Status of Biological Control of The
Elusive Banana Weevil in Africa
10:00 am: Scientist James Legg Flying Together?–Geminiviruses and Whitefly
10:30 am: Coffee Break
11:00 am: General Discussion for Project B
11:30 am: Coordinator Gockowski 2003 Highlights of Project C: Assessing Impact,
Formulating Policy Options, and System Analysis
12 noon: Postdoctoral Fellow Abele Market-Driven Agriculture and
Commercialization in Africa
12:30 pm: Buffet Lunch
Afternoon Session Chairman: RDC Councilor Manyong
1:45 pm: Scientist Kormawa Rural Livelihood and Poverty Mapping: Contribution
to R4D Priority Setting
2:15 pm: FOODNET Coordinator Ferris Globalization, African Agriculture, and the
2:45: pm: General Discussion for Project C
3:15 pm: Coffee Break
3:30 pm: Coordinator Whyte 2003 Highlights of Project D: Promoting Food
Security and Income Generation Through Sustainable Production and
Commercialization of Starchy and Grain Staples in Eastern and Southern Africa
3:55 pm: Visiting Scientist Okech IPM on East African Banana–Coffee Systems
4:20 pm: VVOB Scientist Dochez Status of Host Plant Resistance Breeding to
Nematodes in Musa Germplasm
4:45 pm: Scientist Andrade Multiplication and Distribution of Superior Planting
Materials–Postharvest Intervention Activities
5:10 pm: SARRNET Coordinator Mahungu Marketing Cost of Cassava and Sweetpotato
in South Africa: The Case Study of Malawi, Tanzania, and Zambia
5:30 pm: General Discussion for Project D
6:00 pm: Adjourn
7:00 pm: Pizza Night at I-House terrace and swimming pool
Open Plenary Day 3: Saturday 6 December 2003
Morning Session Chairman: RDC Councilor Neuenschwander
8:15 am: Coordinator Tenkouano 2003 Highlights of Project E: A Future Through
Farming–Enhancing Livelihoods, Improving The Resource Base and Protecting
The Environment Through Starchy Staple, Peri-Urban and Tree Crop Systems
of The Humid and Subhumid Zones of West and Central Africa
8:45 am: Scientist Nolte Legumes in The Cropping Systems of The Humid Forest
9:15 am: Assoc. Scientist Shiwachi Improving Yam Planting Materials and Crop
9:45 am: Junior Prof. Robiglio Managing Resources in The Congo Basin
10:15 am: Coffee Break
10:30 am: General Discussion for Project E
11:00 am: Coordinator Singh 2003 Highlights of Project F: Improving and Intensifying
Cereal-Legume Systems in The Moist and Dry Savannas of West and Central
11:30 am: Scientist Chikoye Integrated Control of Imperata and Other Weeds
12 noon: Scientist Emechebe Managing Striga on Cowpea and Maize Cropping
12:30 pm: Scientist Diels Matching Crops and Soils Using Integrated Natural Resources
Management in The Dry and Moist Savannas
1:00 pm: General Discussion for Project F
1:30 pm: Buffet Lunch
7:00 pm: Annual WPW Party
Sports Day: Sunday 7 December 2003
Tournaments for Badminton, Cross-Country, Golf, Squash, Tennis, and others to be
announced by organizers
Project Planning Day 1 (Closed to Project Members): Monday 8 December 2003
8:00 am: Project A – Building 400 Meeting Room
Project B – Auditorium
Project C – Building 401 Meeting Room
(10:15 am: Coffee Break in meeting venues)
12:30 pm: Buffet Lunch
1:45 pm: Project D – Building 400 Meeting Room
Project E – Building 401 Meeting Room
Project F – Auditorium
(3:30 pm: Coffee Break in meeting venues)
5:30 pm: Adjourn
7:00 pm: Quiz Night at I-House Executive Dinning Room
Project Planning Day 2 (Closed to Project Members): Tuesday 9 December 2003
8:00 am: Project D – Building 400 Meeting Room
Project E – Building 401 Meeting Room
Project F – Auditorium
(10:15 am: Coffee Break in meeting venues)
12:30 pm: Buffet Lunch
1:45 pm: Project A – Building 400 Meeting Room
Project B – Auditorium
Project C – Building 401 Meeting Room
(3:30 pm: Coffee Break in meeting venues)
5:30 pm: Adjourn
Restricted Plenary Day (Only for IITA): Wednesday 1 December 2003
Morning Session Chairman: RDC Councilor Dixon
8:30 am: Coordinator Ingelbrecht – Report from Project A
9:00 am: Coordinator Tamo – Report from Project B
9:30 am: Coordinator Gockowski – Report from Project C
10:00 am: Coffee Break
10:30 am: Coordinator Whyte – Report from Project D
11:00 am: Coordinator Tenkouano – Report from Project E
11:30 am: Coordinator Singh – Report from Project F
12 noon: General Discussion for last day morning session
12:45 pm: Buffet Lunch
Afternoon Session Chairman: RDC Councilor Asiedu
2:00 pm: CFO Estoque Numbers at IITA Budget: Looking at 2003 Backwards
and 2004 Outlook
2:20 pm: CIS Head Mowbray Updates in the Research to Nourish Africa
2:40 pm: CS Head Osotimehin Servicing Needs to Assist IITA Research-for-
Development Beyond Headquarters
3:20 pm: ITC Head Scott E-Information & Communication Technology @ IITA
3:40 pm: Coffee Break
4:00 pm: C&GO Schöning The Functions of the Contracts and Grants Office
4:30 pm: Closing WPW Remarks – Principal Scientist Neuenschwander, RDC
Chairman Ortiz, IITA Director General Hartmann
5:00 pm: Adjourn
6:30 pm: Suya evening at Cappa Bar
Priority Setting and Scaling Innovations for IITA Research-for-
Victor M. Manyong
Diminishing contributions (to agricultural research) from the international community and
a search for greater efficiency require that scarce resources be allocated selectively to programs
and projects within a research institution such as IITA. While resources are dwindling, the
demand is increasing for impact from basic and applied research to reverse the negative trend
in poverty and food insecurity in sub-Saharan Africa in a sustainable manner. Therefore,
there is the need to develop and apply sound approaches to set priorities and successfully
extrapolate research findings from local to regional, national, and continental levels.
At IITA, such strategies for the setting of priorities and extrapolation of innovations
are undertaken within the framework of the IITA MTP Project entitled Impact Assessment,
Formulating Policy Options, and Systems Analysis. We consider that priority setting is an inte-
gral part of an iterative research process that includes elements such as the problem census,
ex-ante impact assessment of alternative options, impact generation, adoption studies, and
ex-post impact assessment. Scaling of innovations contributes to this process in two comple-
mentary ways: geographic and social. The geographic scaling up refers to a spatial targeting
of innovations while the second way refers to social processes involved in the adoption and
adaptation of innovations. Social scaling further makes a distinction between the horizontal
dimension (or scaling out), the vertical ascendant dimension (or institutional scaling up),
and the vertical descendant dimension (policy scaling or scaling down).
The implementation of strategies for both priority setting and scaling of innovations
requires the combined use of soft, qualitative, and participatory techniques on the one side
and of hard and quantitative methods on the other in order to conduct rigorous and authori-
tative analyses. The importance of the role of stakeholders in the above processes has always
been emphasized. A successful priority setting exercise must be based on the needs of, and
conducted in collaboration with major clients such as SROs, NARES, the private sector, and
other end-users (farmers and consumers). Such an exercise must also take into consideration
the comparative advantage of IITA. Similarly, stakeholders play a critical role. For example,
farmers and research institutions are the key to the success of the horizontal scaling out of
innovations; local institutions and NGOs contribute more to the vertical ascendant (scal-
ing up) while the private sector and policymakers are important catalysts for scaling down.
Examples drawn from recent IITA experiences indicate that one single approach is
not powerful enough to address all the issues related to priority setting and extrapolation
of technologies. Therefore, we advocate flexibility and pragmatism in dealing with the
Ecofriendly Integrated Pest Management: Concept and Imple-
mentation at IITA
Integrated Pest Management (IPM) has its origin as a strategy to avoid the misuse of pesti-
cides. It dates from the late 1950s, when cheap organo-chlorides, which accumulate in the
soil and food-chain, led to major ecological disasters. While the most persistent products were
banned in the 1990s, the concept was extended to other products such as the highly poison-
ous organo-phosphates and later, a series of less disruptive, but still rather wide-spectrum
insecticides and acaricides. Today, the mantra of practitioners as well as the chemical industry
proclaims the minimum, so-called “judicious”, use of insecticides in combination with all
other techniques, such as cultural control methods, resistant varieties, and biological control,
both manipulated (“inundative”) and naturally occurring. While this concept could be a
good practical guide, it is very often abused and serves as a cover for unnecessary insecticide
use. FAO is therefore promoting the notion that the IPM label cannot be applied when the
most hazardous chemicals (organo-phosphates and others) are used and USAID bans their
use in its projects. Also the eco-friendliness of all interventions needs testing, which itself
requires a clear idea of the goals. This text discusses the following issues:
• The situation in Africa: self-sufficiency and the social costs of insecticide-free
• By what means is sustainable food production to be achieved?
• Which ecosystem is it that we want to preserve or rehabilitate?
• What are the envisaged time horizons and when and where does one start?
• How has IITA approached the conflicting goals inherent in IPM?
• What methodologies are best used to move in the right direction?
• The vision: Do we have to repeat USA and European history or can we find a path to
sustainable production in the developing world?
Many answers to these questions exist, but might not be popular and acceptable;
many require a rethinking of our priorities. Others need urgent research. The importance of
biological control as the centerpiece of all IPM is stressed. While ecofriendly IPM is a highly
popular notion, it is not an easy concept.
Genetic Resources and Biotechnology
The genebank of IITA conserves accessions of the Institute’s mandate crops, multipurpose
trees, and other indigenous African species such as Bambara nut as seed, in the field, and/or in
vitro. The accessions have been subjected to various levels of characterization and evaluation
and have been distributed upon request, especially to NARS partners. Further improvements
in characterization and evaluation are planned, based on strategies such as using descriptors
less influenced by environmental conditions; using standard check accessions to compare data
across seasons; rationalizing the collection for the evaluation of the core collection, regional
collection, and working collection; and using standard protocols and scoring systems.
These and other aspects of the genebank’s operations could benefit from developments in
molecular biology. Molecular markers are very useful in the identification of duplicates,
diversity analysis to identify needs or gaps in the collections, and the estimation of genetic
relationships. They can also facilitate the utilization of wild species through wide crossing
as well as the general exploitation of useful diversity in unadapted germplasm. Molecular
diagnostics can be very effective and efficient in the detection and elimination of seed-
borne pathogens for the purposes of storage and to meet quarantine requirements in dis-
tribution. The strategy to enhance the utilization of accessions in the genebank hinges on
further characterization, evaluation, and documentation; improved pathogen diagnosis;
development of core collections and trait specific genepools; and establishment of regional
More recent discoveries in molecular biology could be further applied to the wealth of
available genetic resources in order to gain a better understanding of the genetic structure of
the collections and to derive maximum benefit for the ultimate beneficiaries of IITA’s work.
Structural and functional characterization of available germplasm (including wild relatives,
landraces, breeding lines, cultivars, mapping populations, and genetic stocks) will help in
identifying new alleles, genes, and pathways that can be linked to functions and traits. The
most useful alleles and genes would be made available to breeding programs after validation.
The approaches for this will include selection of suitable genetic resources for diversity analy-
ses, selection and use of appropriate marker systems for structural and functional diversity
assays combined with high-throughput genotyping, phenotypic analyses, identification of
novel variants (e.g., through association genetics and allele mining) and subsequently com-
parative genetics across crop species.
The foregoing will require strong links with the private sector and attention to the man-
agement of intellectual property in line with the Institute’s policy for ensuring that products
remain in the public domain. In this context, the potential implications of the International
Treaty on Plant Genetic Resources (IT-PGR) on the operations of the genebank deserve
consideration. Facilities in the genebank and biotechnology laboratories, including those for
information management may require some upgrading. It is also important that links with
breeders are maintained to ensure that products feed efficiently into populations from which
improved varieties will be selected for the ultimate beneficiaries from the work of IITA.
Crop Improvement and New Tools For Managing Genotype-
by-Environment Interactions, Parental Selection, and
Participatory Breeding in Africa
Agricultural production may be increased through improved efficiency in the utilization of
resources such as increased productivity per unit of land and of money, and through a better
understanding and utilization of the genotype-by-environment interaction (GEI). Constant
and sustained efforts are made in the judicious choice of parents and their subsequent use in
crosses in order to increase the efficiency of the hybridization programs. In addition, the pref-
erences and desires of consumers/endusers (families, women, children–rural and urban) for
crop products should be considered in the development of improved germplasm. Suboptimal
resource use by farmers and inadequate agricultural extension in developing countries also
strongly favor the use of alternative strategies for crop improvement. Innovative strategies/
tools used to increase the efficiency in utilization of resources in crop improvement include
genotype and genotype by environment (GGE) biplot methodology, geographic informa-
tion system (GIS); participatory plant breeding approaches (PPB); biotechnology (tools of
modern molecular biology), cutting edge research technologies and/or analytical tools; and
Internet-based networking, databases, and information exchange.
Crop performance (observed phenotype) is a function of genotype (variety or cultivar),
environment and GEI (a major concern among breeders, geneticists, production economists
and farmers because of its universal presence and consequences). GEI is said to occur when
different cultivars or genotypes respond differently to diverse environments (different geno-
types are superior in different environments). This has necessitated multienvironment trials
(MET) and has resulted in the development and use of numerous concepts and measures of
stability in its understanding and management. Selection only for stability is inconsequential
if the production level is ignored, and GEI and stability of crop performance across environ-
ments are expected to become more relevant issues in the 21st century as greater emphasis
is placed on sustainable agricultural systems.
As “one picture is worth ten thousand words”, the GGE biplot methodology is by far the
best approach for the visual analysis of large two-way and multivariate datasets, particularly
from breeding and genetics research. The GGE biplot methodology helps plant breeders to
understand and explore GEI, and requires that G and GEI be regarded as integral parts in
cultivar evaluation and plant breeding. Among its many functions in a user-friendly software
package, GGE biplot displays the “which-won-where” pattern of a multi-environment trial
dataset and addresses the issue of mega-environment differentiation. It displays both mean
performance and stability of tested varieties, and ranks them on integrated standards; displays
both discriminating ability and representativeness of the test environments and ranks them
on integrated standards; displays the relation among the test environments; displays inter-
relations among various breeding objectives (traits) based on genetic values, environmental
values, or phenotypic value; and helps the breeder to achieve a systems understanding of his
plant to identify appropriate breeding strategies, to identify superior varieties (as packages of
traits), superior parents (good in a particular trait), and appropriate traits for indirect selec-
tion for a target trait. More recently, the GGE biplot is used in identifying genetic regions
associated with a particular trait [quantitative trait loci (QTL) mapping] and in displaying
QTL by environment interactions (called QQE biplots), which has long been a challenge
GIS (an organized collection of computer hardware, software, geographic data, and
personnel) is designed to efficiently capture, store, update, manipulate, analyze, and display
geographically referenced information. In agricultural and natural resource management, GIS
is considered as a valuable tool in the studies related to research planning, better targeting
of research products, and assessing impacts of research. Some applications of GIS in crop
improvement include fitting varieties to environments; developing a resource inventory
showing the distributions of crops, climate and soils resources and biotic and abiotic stresses
of crops; relating the biophysical variables and the adoption rates of improved varieties for a
better understanding of technology diffusion/adoption; the estimation of spillover impact of
crop germplasm; the delineation of adoption and adaptation zones for crops for the region-
alization of technology development, testing, and application. It guides the search for new
samples of the genetic diversity of cultivated and wild crop species; and relates disease inci-
dence with the climate variables for better understanding of the occurrence of the disease.
Several approaches have been adopted in selecting parents and the planning and
evaluation of crosses in order to produce superior elite genotypes. These include historical
selection records, inherent parental characteristics and breeding performance. The develop-
ment of approaches based on relational databases has greatly contributed in improving the
efficiency in the planning of crosses. Emphasis is being placed on the use of cross prediction
as a new tool in increasing the efficiency of the breeding program, and molecular markers
are a valuable complement to field trials for identifying heterotic groups and introgressing
exotic germplasm systematically. Further progress is expected to result from the application
of molecular techniques in the early screening of potential parents with the ultimate aim of
increasing the probability of selecting superior elite genotypes that meet the objectives of
the crop breeding programs.
In addition, PPB that involves close client/farmer-researcher collaboration to bring
about plant genetic improvement (cultivar selection or breeding and for agronomic
manipulation) within a species increases food security and improves the livelihoods of poor
people in developing countries, and differs from conventional crop breeding by target-
ing specific niches rather than relying upon a uniform package of practices. Participatory
trials are usually kept simple with few treatments, but these trials need not suffer from the
restriction on the number of treatments. With fast speed computers, designs [augmented
block designs (ABD)] useful for large-scale trials with far from a few treatments and with
as many farmers, are available. While the design concepts are not at variance with classi-
cal and commonly known ones, effective analysis of ABDs such as “mother–baby” trials,
requires the use of MIXED modeling procedure (partitioning into fixed and random effects).
The modeling and fitting procedures enable effective recovery of both inter-block and
intra-block variation, and inter-treatment information. Farm and/or farmer heterogeneity
needs to be watched carefully and incorporated in the design as the primary goal is to ensure
wide coverage of the application of treatments or conditions and consequently enhanced
probability of adoption and impact. Examples of these strategies/approaches and tools
will be presented.
Integrated Natural Resources Management—Where We Stand
Integrated Natural Resource Management (INRM) involves multiple stakeholders and links
interventions in production systems (cropping, livestock, and forestry) with all aspects of
natural resource management (water, nutrients, biodiversity, crop improvement, integrated
pest management, carbon storage, etc.), markets and policies.
Research for development (R4D) that aims to reduce poverty and increase food security
without degrading the environment must be undertaken in the context of sustainable INRM.
This approach creates more impact through synergies between individual interventions, such
as soil fertility and crop improvement, and through the cooperation of multiple stakeholders.
Stakeholder participation at different levels of institutions lays the basis for successful scaling
up and out, and should result in greater impact.
At IITA, there are three disciplinary projects (A—Preserving and enhancing germplasm
and agrobiodiversity; B—Developing biological control options; and C—Impact, Policy
and Systems Analysis). These feed research results to three systems projects (D—Starchy
and grain staples in eastern and southern Africa; E—Starchy staples, peri-urban, and tree
crops of the humid and subhumid zones of West and Central Africa; and F—Intensified
cereal–legume–livestock systems in the moist and dry savanna of West Africa). Assessment
of the various activities in the systems projects indicates that there are nominal INRM out-
puts. However, the integration of individual activities that would lead to greater impact is
often weak. Within the institute, however, there are some special projects applying INRM
approaches (e.g., STCP, PROSAB, RUSEP, crop–livestock integration, Dfid-weeds).
The key to operationalizing INRM within the R4D context is not to have an INRM
working group as presently constituted, but to formalize INRM issues within the institute.
For example, each of the projects could have INRM outputs as INRM issues cut across
projects. This will show a stronger institutional commitment, and also show an integrated
approach in addressing INRM within the institute. Some threats to INRM implementation
would include difficulties in assembling all necessary stakeholders, facilitating the process of
resource mobilization, and managing the multidisciplinary team.
Project A: Preserving and Enhancing Germplasm and
• First report of production of yam microtubers from single nodal cuttings of screen
house grown plants for D. rotundata; the frequency of microtuberization from screen
house grown material was considerably higher when compared to microtuberization
from in vitro grown plantlets (over 30% versus less than 5%), offering new perspec-
tives for distribution of yam propagules
• Eighteen improved cassava varieties were analyzed for their amino acid profile in
the leaves to determine protein quality. On average, the amino acids glutamic acid
and leucine were highest with values above 4g/100g protein followed by aspartic
acid, arginine, and alanine with values above 3g/100g protein. The sulphur amino
acids cysteine and methionine had the lowest values of less than 0.5g/100g protein.
Among the varieties, TME279 had the highest concentration of the essential amino
acid lysine (3.7g/100g).
• Iron bioavailability of 20 elite and adapted late maturing maize varieties was assessed
using the Caco-2 cell model. Significant differences in bio-available iron were
observed among varieties. Mean bio-available iron ranged from 14% below to 43%
above the reference variety, TZB-SR.
• The sugar, starch and dry matter content as well as pasting properties of 49 yam
varieties were determined at the advanced yield trial stage. Significant differences
were observed among the varieties for each characteristic: dry matter content ranged
from 19 to 37%; sugar from 2.4 to 11%, and starch from 34 to 65%. The pasting
temperature ranged from 64 to 84°C.
• Transgenic shoots of plantain have been generated that contain a resistance gene
derived from Banana Streak Virus (BSV) for further testing of BSV resistance and
production of BSV resistant plantains.
• An efficient and reproducible shoot regeneration system was established for cowpea
(Vigna unguiculata L Walp.) using embryonic axes as explants. Conditions for genetic
transformation with Agrobacterium tumefaciens and selection using the kanamycin
resistance gene have been optimized.
• Molecular diversity studies were conducted on wild cowpea (48 accessions of ssp.
dekindtiana, ovata, mensensis, rhomboidea, grandiflora, congolensis, protracta and
pubescens); water yam (53 accessions of Dioscorea alata L. from West Africa and
Puerto Rico); cassava (96 cultivars from Sierra Leone); cocoa (over 500 accessions
from Nigeria) using SSR and/or AFLP markers.
• Heterotic groups of the new mid-altitude maize inbred lines were established using
yield-based combining ability and molecular markers. Considering the diversity of
the genetic backgrounds of the inbred lines, the marker-based grouping may serve
as the basis to design and carry out combining ability studies in the field to establish
clearly defined heterotic groups with greater genetic similarity within groups.
• Three AFLP markers identified in maize that detected differences between bulks
for numbers of emerged Striga plants and one AFLP marker that separated
the two bulks for Striga damage symptom rating were confirmed in a second
• About 26 cassava tetraploid clones (2n = 4x =72) were produced following colchicine
treatment of buds from 60 improved and diploid cassava genotypes. Pollen stainabil-
ity of the tetraploids ranged between 12% and 78% with a mean of 50.9% while that
of their diploid counterparts ranged between 32% and 95%, with a mean of 70.5%.
The pollen size of tetraploids ranged between 80µ and 140µ, while that of their
diploid counterparts ranged from 70µ to 110µ. The stomata pore count for
tetraploids ranged from 42 to 106 per unit area while that of their diploid
counterparts ranged between 52 and 130 per unit area.
• A diagnostic survey was conducted in southern Nigeria to monitor changes and
spread of the Cassava Mosaic Disease (CMD). This study revealed that the Ugandan
strain of EACMV, i.e., the causative agent of the CMD epidemic in Uganda, is not
yet present in Nigeria. However, mixed infections of ACMV and EACMV which
gave rise to the recombinant Ugandan strain are now widespread in southern
Nigeria and virulent strains of ACMV and EACMV inducing very severe
symptoms are already present in the survey area.
• New sources of resistance to CMD were identified in cassava landraces from Ghana.
• Hybridization between several African landraces and improved cultivars of cassava
and castorbean (Ricinus communis L.), both members of the family Euphorbiaceae,
was achieved. Plantlets were recovered after embryo rescue and multiplied for
morphological and molecular analysis. All plants are morphologically similar to
cassava. Preliminary molecular analysis indicates that true hybrids have been
• Two hundred local landraces of cassava have been collected from 7 out of 11
provinces in the DR Congo and maintained at Mvuazi Research Station for
subsequent duplication at the IITA genebank at Nigeria.
• Over 20 000 in vitro plantlets of 10 improved and multiple pest and disease-
resistant cassava clones have been produced for further introduction into
DR Congo. About 1500 in vitro plantlets have been distributed to DR Congo
to combat the CMD epidemic. Also, the tissue culture laboratory at the Mvuazi
Research Station in DR Congo is being upgraded with a capacity to produce 2000
pathogen-tested in vitro plantlets per month.
• Thirty-six newly selected improved cassava genotypes incorporating multiple pest
and disease resistance, including CMD resistance, early bulking storage roots with
high dry matter, low cyanide, good cooking quality, ease of peeling, good root shape,
and appropriate plant architecture have been developed for a range of agroecologies
and are being disseminated to national programs.
• Forty-two high-yielding cassava genotypes with beta-carotene enriched storage roots
have been selected and multiplied for participatory selection with farmers in various
• Forty-six new and diverse CMD-resistant varieties were nominated and a total
of 251 486 plants established in 17 ha of land; three improved cassava varieties
popularly grown by farmers varieties were multiplied in five agroecologies of
Nigeria to combat the imminent threat of CMD.
• New and diverse CMD-resistant cassava varieties have been planted in 11 States
of southern Nigeria in a preemptive CMD management program.
• Three improved and multiple pest and disease-resistant cassava varieties
originating from IITA were officially released by the Government of Ghana
for the Guinea savanna agroecologies of Northern Ghana.
• Upgrading of the IITA genebank was initiated with information of germplasm
being curated and made available on the intranet; rejuvenation of the Bambara
groundnut collection (1400 accessions) was completed.
• Three Striga-resistant and high-yielding maize varieties have been identified in
the Regional Early Striga Variety Trial and recommended to WECAMAN
member countries for on-farm evaluation.
• Preliminary results indicated that the field resistance of the IITA Striga-
resistant maize inbred lines does not rely on low stimulant production to
Striga seed germination but rather on post-attachment resistance mechanisms.
• A herbicide resistance gene (imizapur resistance gene) that inhibits acetolactate
synthase activity and growth of Striga was introgressed into tropical maize adapted
to the savannas to allow effective control of Striga by treatment of maize seed with
low doses of imizapur.
• With backstopping from IITA, a Musa breeding program was established at the
Centre National de Recherche Agronomique of Côte d’Ivoire—the first NARS in
West and Central Africa to initiate a plantain breeding program.
• Genetically segregating populations of bananas were produced by selfing of Musa
balbisiana, and by interspecific crossing of Musa balbisiana and Musa acuminata,
which will allow the genetic analysis of genes contributing to nematode resistance,
earliness, plant height, and water use efficiency in diploid banana.
• The first scientifically verified apomixis (i.e., the production of seed in the absence
of fertilization), has been genetically and phenotypically characterized in banana,
paving the way for counterselection against this trait in breeding programs.
• Sources of embryo lethal genes, useful for the production of seedless bananas and
plantains, were identified in IITA improved bananas and plantains and have been
genetically and phenotypically characterized.
• A dwarf and early-maturing secondary triploid plantain hybrid was produced with
resistance to black Sigatoka and derived from high-yielding PITA17 and nematode-
resistant Moron princesa.
• Three technicians from the National Root Crop Research Institute, Umudike,
Nigeria, were trained at IITA in cassava production and rapid multiplication,
breeding and postharvest utilization. In addition, two technicians from DR Congo
were trained at IITA in cassava breeding and postharvest development.
• About 410 yam plantlets, 11 425 yam minitubers, 103 Musa plantlets, and 2 241
cassava plantlets have been distributed to various partners in sub-Saharan Africa
and the Fiji islands.
• The third Annual Conference on USAID-African Partnerships in Biotechnology
co-organized by USAID, ABSP II and IITA was held in Ibadan, Nigeria, back to
back with the Stakeholders Workshop of the Nigerian Agricultural Biotechnology
Program launched in 2003.
• Three visiting fellows from 2 Nigerian NARS, one technician from IITA-HFC
and two students from the University of Ibadan were trained in micropropagation
of cassava and yam.
A large number of improved cowpea breeding lines combining resistance to Striga and
drought tolerance were developed. Genetic studies on plant, flower, and pod pigmentation
in cowpea was completed. A total of 50 selected cowpea varieties were analyzed for protein
and micronutrient contents and great deal of variability was observed.
Cocoa Genetics–The First Step to Understanding Chocolate
Quality: Assessment of Genetic Diversity in West African
Cocoa Collections Using Molecular Markers
M. Kolesnikova-Allen, P.O. Aikpokpodion, K. Badaru, R. Bhattacharjee, and
Cocoa powder, used in the manufacture of chocolate, is obtained from beans of the
cacao tree, Theobroma cacao L. (2n = 2x = 20), with more than 70% of the total world’s
production (2.9 million tonnes) coming from West Africa. Cocoa cultivation is mainly a
smallholder enterprise in this region with farm sizes often less then 2.0 hectares. However,
it is not only indispensable to the economy of this region as an important source of for-
eign exchange revenue but also critical to the profitability of the chocolate industry in the
Since its first introduction to West Africa by the Portuguese and Spaniards in 1722, sev-
eral cocoa germplasm pools belonging to Lower and Upper Amazon Forastero, Trinitario, and
Criollo populations, as well as their hybrids, have entered farmers’ cultivation. Consequently,
in both NARS’ field genebanks and farmers’ collections of cocoa, a wide range of genetic
variability is now present which could be further exploited for improving yield, quality of
products, and resistance to biotic and abiotic stresses. However, little documentation exists
in West Africa as well as in individual countries within the region on the extent of cocoa
genetic variability and the impact of traditional farming practices on its structure. Therefore,
the use of DNA-based molecular markers (SSR), developed by CIRAD and USDA-ARS
Miami, will provide an efficient and quicker means of assessing the genetic variability pres-
ent in these populations.
Among various biotic constraints in cocoa production in this region, those that cause
most concern are the black pod disease, caused by Phytophthora megakarya and P. palmivora,
leading, when uncontrolled, to yield losses from up to 80% to 100% (total yield loss) and
swollen shoot disease, caused by the swollen shoot virus. Therefore, the challenge ahead for
the sustainability of cocoa production is to provide improved germplasm to farmers with
combined high productivity and disease resistance. The major objectives of the present
study, therefore, are to determine the range of genetic diversity present in West African cocoa
germplasm, produce fingerprints of selected accessions used in NARS’ breeding programs,
and identify sources of resistance to diseases in available cocoa germplasm. The study will
be carried out at IITA, Ibadan, Nigeria, in collaboration with the USDA-ARS Subtropical
Horticulture Research Station in Miami, USA, and NARS partners in West Africa—the
Cocoa Research Institute of Nigeria (CRIN), Nigeria, the Cocoa Research Institute of Ghana
(CRIG), Ghana, Institut de Recherche Agricole pour le Développement (IRAD), Cameroon,
and the Centre National de Recherche Agronomique (CNRA), Côte d’Ivoire with whom
the memoranda of understanding and project agreements were signed. This project is a part
of the internationally coordinated genetic-marker oriented cacao research program involv-
ing Central and South America with a global initiative to identify germplasm as sources of
resistance to major diseases and abiotic stresses.
Presently, the germplasm collections are underway in Nigeria, Ghana, and Cameroon. A
farmer participatory approach is being used in collecting germplasm, during which farmers
are requested to indicate the “best” and “worst” performing trees with respect of yield and
the incidence of black pod disease. All collected accessions are accompanied with GPS and
morphological data. Beans are collected to conduct butterfat content. Budwood has been
taken from all collected accessions to establish nurseries at NARS stations. DNA maxi-prep
extractions have been performed in IITA from the Nigerian collection (400 accessions). In
Ghana, DNA extractions are carried out by CRIG team from their collection and will be
passed later to IITA for the following marker analysis. DNA extraction protocol for high
throughput application is being optimized in IITA, allowing the extraction of up to 200
samples of DNA/day. PCR conditions for running coca SSR markers are optimized and ABI
310 Semi-Automated Sequencer run conditions are in the process of fine tuning.
This study will further provide the basis for exploration of heterosis in improved cocoa
cultivars; introduction of cocoa germplasm and its utilization; choice of clones and accessions
in creating uniform populations or hybrid progenies with higher levels of production, bean
quality, and resistance to biotic and abiotic stresses.
What Cowpea Genetics Tell About Germplasm Improvement
Cowpea is one of the most important food legumes in the drier regions of the tropics
and subtropics covering over 60 countries but it is especially important in sub-Saharan
Africa, where it originated and is widely grown and consumed in many forms. Under the
Consultative Group on International Agricultural Research (CGIAR), the International
Institute of Tropical Agriculture (IITA) has a global mandate for the cowpea research and
development program. It has a world collection of about 16 000 cowpea germplasm lines
which are used as a source for genetic studies and breeding programs by cowpea researchers
around the world.
Among the cultivated crops, cowpea is one of the most variable species and genetic
variability is the basis of genetic enhancement. Extreme cowpea genotypes have
been observed with respect to many traits and genetic studies have identified over 207 genes
which control plant pigmentation, plant type, plant height, leaf type, growth habit,
photosensitivity and maturity, nitrogen fixation, fodder quality, heat and drought toler-
ances, root architecture, resistance to major bacterial, fungal and viral diseases, resistance to
root-knot nematodes, resistance to aphid, bruchid and thrips, and resistance to para-
sitic weeds such as Striga gesnerioides and Alectra vogelii, pod traits, seed traits, and grain
quality. Limited studies have also been conducted on genetic maps including classical as
well as DNA markers. Quantitative genetic studies on the heritability of yield and yield
components and protein content, etc., and heterosis for important traits and improved
breeding methods have facilitated the selection of parents and increased the efficiency in
Using the vast genetic pool and useful genes already identified, great progress has been
made through conventional methods in breeding a range of high yielding cowpea varieties
with combined resistance to major diseases, insect pests, Striga and Alectra, and drought
tolerance. For example, combining erect plant type with early maturity and resistance to
major pests, new extra-early cowpea varieties have been developed which yield up to 2.5 t/ha
within 60–65 days compared to less than 1 t/ha from the local varieties which mature in
100 to 140 days. Efforts are now underway to exploit biotechnological tools to complement
conventional methods for improving insect resistance and quality traits in cowpea.
The large number of useful genes in cowpea are presently being used to improve cowpea
productivity but with emerging advances in biotechnological tools and genomics, several of
the desirable genes from cowpea can be identified, isolated, and used to enhance germplasm
in other crops as well. Some of these include genes for growth habit, early maturity, photo-
insensitivity, resistance to several viral, bacterial and fungal diseases, nematodes, Striga, Alec-
tra, aphid, bruchid and drought tolerance, salt tolerance, acid tolerance, and other adaptive
traits for the dry lands and the Sahelian region. This may be possible because most of these
traits are simply inherited and a DNA marker-based map for cowpea is available. Cowpea
can also be used as an alternative experimental crop for biotechnological studies in addition
to Arabidopsis since the earliest cowpea varieties reach physiological maturity in 50 days
permitting the planting of at least 5 generations each year.
Managing A Puzzle Through Banana/Plantain Functional
One primary focus within Project A is to develop the genetic tools for functional genomics
applications that may assist in a cost-effective fashion in the Musa breeding program. One
focus of our integrative approach is to develop germplasm, and genetic and genomics tools to
be used in a breeding process, for more cost-effective selection for a trait of seedlessness. The
primary breakthroughs in the Musa Genetics and Functional Genomics program in the past
year have been in the elucidation of the genetic “puzzle” of the trait of asexual seed production
as it relates to a trait of parthenocarpy (fruit development in the absence of fertilization), and
to the trait of seedlessness by embryo lethality. Fertile Musa comprises hard and stony seeds
that reduce the edible pulp of the fruit and pose a threat to the dental health of consumers.
The genetic basis of seedlessness may be produced by: (1) a combination of coexpression of
traits of female infertility and parthenocarpy; or (2) fertilization and subsequent abortion of
embryo or seed development, with continued fruit development. In a typical Musa breeding
screen, up to 90% of all plants must be discarded after an investment of up to 2 years of care,
with land area costs based on each plant requiring a 6-square meter planting space, because
they produce seed. If, for example, the proportion of seedless Musa is increased such that
50% of progeny are seedless, then effectively the equivalent of 10 years of breeding may be
performed in 2 years, or the effective breeding cost will be reduced by 80%.
Embryo lethal genes in IITA improved tetraploid plantains and IITA improved diploid
bananas have now been genetically characterized. New tetraploid plantain breeding lines
have been established (e.g., IBD 2003-90), and are even now being established containing
early embryo lethal genes from PITA14, an IITA-registered tetraploid plantain of high
adoption in West and Central Africa. Such breeding lines that comprise different plantain
maternal backgrounds when outcrossed, should maximize hybridity and genetic diversity
in the progeny, while at the same time increasing the proportion of seedless progeny, via the
expression of early embryo lethality.
One other breakthrough has been the first genetically and phenotypically verified discov-
ery of apomixis in bananas. Apomixis is defined as a trait of seed development in the absence
of fertilization; it is typically heavily dependent on genotype × environment interactions,
and genetically is expressed via a maternal effect. The banana Borneo has been identified as
containing a trait of apomixis, as has at least one of the IITA improved breeding lines (e.g.,
Tmbx 8084-1). In a cross (28383) of Borneo (nonparthenocarpic) × SF247 (parthenocarpic),
only two classes of progeny are identified: (1) apomictic and nonparthenocarpic; and (2)
nonapomictic and nonparthenocarpic. Analysis of duplicate populations indicate a ratio of
ca. 1:3 (58:185) of these phenotypic classes. The expectation, is that the first phenotypic class
might logically comprise apomictic clones of the Borneo maternal parent, as well as sexually
produced plants resulting from this dihybrid cross, so this ratio is unlikely to be indicative
of the segregation in the progeny of parents comprising single heterozygous recessive alleles
for apomixis, as might be predicted offhand, by the raw data. Using molecular markers,
the apomicts can be identified in the population, providing a means for the identification
of apomictic alleles by genetic segregation analysis, after the removal of the apomicts from
the population structure. Musa breeders have long been puzzled, for example, by G × E
interactions that appear to affect seed production in a particular cultivar. It would thus be
useful to unravel the complexities of this “puzzle”, to determine whether apomixis plays a
role in this phenomenon, and perhaps to be able to counterselect against the genetic basis
of this undesirable trait.
Project B: Developing Biologically-Based Pests, Disease, and
Weed Management Options, and Conserving Biodiversity for
The transmission efficiency of Cucumber mosaic virus (CMV) by a single aphid was found
to be between 19 and 27% indicating that low vector populations are capable of high rates
of spread. The virus can be transmitted from Musa sp. to V. unguiculata. The probability
for spread within a mixed farming system is high, especially as CMV also occurs in weed
species. Losses due to CMV can be high where there is super-infection by other viruses (and
BSV is endemic) or where there is poor management. Since the virus can, to a large extent,
be identified visually, roguing of infected plants becomes an important control option for
reducing inoculum pressure.
The mango mealybug was for the first time observed in Burkina Faso during a survey
conducted in October 2002. The presence of both parasitoids Gyranusoidea tebygi and
Anagyrus mangicola was confirmed, with results showing that the parasitoids are beginning
to have impact on mango mealybug populations.
In West Africa, the two parasitoids Encarsia haitiensis and E. guadeloupae have always
followed their host, the spiralling whitefly, since its accidental introduction in 1992. In
Cape Verde they had been absent until they were taken from our laboratory in Cotonou
and released in the field in 2002. This is therefore the first record of deliberate release and
establishment of these two parasitoids.
The surface coverage index (1 to 20 scale) by water hyacinth in Bénin has declined from
a mean of 12.75 in 1991/2 to 3.29 in 2002 (the last year with complete data), indicating
a substantial general reduction on eight of the nine sites monitored. However, seasonal
fluctuations can still be observed.
Children who were fully weaned on maize-based porridge had higher aflatoxin blood
levels than those still partially breast-fed. The highest quartile of aflatoxin blood levels was
associated with a mean 1.67 cm reduction in growth over 8 months compared to the lowest
Adoption of improved clay stores for the storage of maize grains was found to be
negatively correlated to the proximity to a market, and positively correlated to the years
of farming experience, access to extension service, the extent of maize production, and the
possibility to reduce maize losses.
Banana weevils may be aggregated at or near pheromone lures where they may be infected
by Beauveria bassiana. The weevils remain longer at such lures than conventional psuedostem
traps, thereby facilitating adherence of B. bassiana spores to the insects. Infected banana
weevils remain active in the field and can infect other weevils.
Laboratory studies on antibiosis against banana weevil showed that larvae had
longer development periods on resistant clones, but that survivorship and pupal weight
could not be related to the level of banana susceptibility to this pest. This means that under
current rearing methods, laboratory studies cannot replace field evaluations in screening
germplasm. Larval developmental rate, survivorship, and size were all lower on pseudostems
than on corms.
A survey in Bénin revealed high prevalence of the entomopathogenic fungus Neozygites
fresenii with up to 96% infection of cowpea aphids in the Ouémé valley with aphid
infestations below 10 aphids plant-1 in most fields. Similar trends, although less pronounced,
were observed near the valley. However, in the west and center parts of Bénin, low prevalence
of N. fresenii was recorded and aphid infestations were very high beyond 200 aphids plant-1.
In the north, no aphid infected by N. fresenii was recorded.
In collaboration with Cornell University, USA, an isolate-specific molecular diagnostic
tool was developed for distinguishing African and Brazilian isolates of Neozygites tanajoa,
a fungal pathogen of cassava green mite (CGM). Brazilian strains of the fungus are under
evaluation as microbial control agents of CGM to complement biocontrol of this pest with
A biochemical tool was developed for monitoring maize pollen consumption by
phytoseiid predatory mites. Maize pollen plays a very important role in the biology of
phytoseiid predators—it enhances their persistence and abundance and hence their ability
to suppress pest mite densities.
Six studies on agronomic impact of CGM biocontrol with the neotropical phytoseiid
predatory mite Typhlodromalus aripo in eastern and southern Africa were concluded in
2003. Cassava root yield gain from CGM biocontrol depended on agroecology and variety.
Protected plants produced 20 to 84% higher yields than plants lacking the predators. This
yield gain is likely to translate into substantial financial and economic benefits for food
security and poverty reduction for the region.
Key factors affecting farmer’s choices of cassava varieties and sustainability of biological
control of CGM in Bénin include high-yielding cultivars, access to planting materials,
storability, and access to markets. The same survey also indicated that there is a need to
include women’s perceptions in the technology development to cater for better processing
and consumer’s demand.
A survey to assess the perception of farmers, rural development and social services agents
on the risks linked to the misuse of chemical pesticides on cowpea and cotton in Bénin
indicated that misuse of pesticides is a common practice. Farmers need more information
and awareness about the health hazards linked to pesticide use, and also about alternative pest
control techniques such as the use of plant extracts and other integrated pest management
On-farm field trials of Plutella xylostella granulovirus against the diamondback moth
in peri-urban vegetable growing sites in Bénin (over 50 farmers in Lokossa, Parakou, and
Cotonou) were an outstanding success. Results showed a net improvement in economic
yield and cabbage weight through the use of PxGV over traditional farmer practices,
and farmers were very impressed with the virus and have renewed optimism for cabbage
ELISA was used to test over 1400 Maruca vitrata samples collected from Vigna
unguiculata, Pterocarpus sp. and Pueraria sp. from both Nigeria and the Republic of Bénin.
Incidence of infection of M. vitrata cypovirus (MvCPV) in different batches ranged from
< 10% to 100%, while about 6% of the M. vitrata larvae were very severely infected with a
very high level of antigen detected in the larvae. Ultimately, we aim to understand the role
of MvCPV in wild populations in order to evaluate the likely impact of redistributing the
virus to areas of low incidence.
A survey for natural enemies of the pod borer M. vitrata in Taiwan confirmed previously
observed high parasitism rates by the braconid Apanteles taragamae on green manure crops
of Sesbania cannabina. Import permits have been obtained to test this promising natural
enemy in our laboratories in Cotonou.
Plantation longevity of plantain cv. Agbagba was increased, crop yield improved and
nematode damage suppressed when organic mulch from wooden chips was applied during
the first cycle. Similarly, early vegetative growth was improved with Tithonia diversifolia
mulch: as little as 2 t/ha mulch doubled plantain fresh weight over a 6-month period in
drums infested with nematodes.
Inoculation studies in Uganda confirmed for the first time that yam tuber
cracking, retarded root growth, and reduced tuber yield are caused by lesion nematodes
Pratylenchus sudanensis. Differences in the susceptibility of yam cultivars to the nematode
were evident in both local landraces (Dioscorea cayenensis) and improved IITA cultivars
Maize growth in the presence of lesion nematodes (Pratylenchus spp.) and soybean
growth in the presence of root-knot nematode (Meloidogyne spp.) were both substantially
improved by the application of microbial antagonists or root symbionts (Mycorrhiza).
Damage to cassava by root-knot nematodes (Meloidogyne spp.) and root rot fungus
(Botryodiplodia theobromae) at 4 months after planting was greatly increased when both
nematodes and the fungus were present.
More than 400 plant protection officers, village brigade members, and farmers
were trained in integrated grasshopper control in Burkina Faso, Cape Verde, Niger, and
About 4500 accessions of the IITA mandate crops excluding 7000 rice varieties
for WARDA were field inspected and seed health tested and certified for international
African Root and Tuber Scale, An Emerging Threat to Cassava
in Central Africa
Rachid Hanna, Maurice Tindo, Georg Goergen, and Leonoor Wijnans
In the Congo Basin, the African root and tuber scale (ARTS) Stictococcus vayssierei (Richard)
has increasingly become a major pest of cassava since it was first identified and described in
the early 1970s. Yield loss trials from the Bas-Fleuve district of the Democratic Republic of
Congo showed that high densities of scale could lead to losses of over 60% of cassava root
yield. The rise in the pest status of S. vayssierei presents a very intriguing case study on how
a native insect (S. vayssierei is restricted to the Congo Basin, and the entire family Stictococ-
cidae is Afrotropical) has evolved into a major problem on an exotic crop plant (cassava is
native to South America). A major effort (funded by IFAD, Austria, and the Netherlands)
is presently underway to identify and characterize biotic, agronomic, and environmental
factors that affect scale abundance, and to develop sustainable management strategies. The
priority is protecting cassava, but later this could be extended to other food crops affected
Research initiated in the last few years by IITA (supported by special project funds from
UNDP, Danida, Austria, and IFAD) in collaboration with national programs from Cameroon
and Democratic Republic of Congo has shed some light on some of the factors that may have
led to the increase in abundance and severity of the scale. Present evidence indicates that S.
vayssierei abundance is affected substantially by land-use patterns prevalent in the forest zone
of Central Africa. Scale densities are higher in cassava fields planted after short fallow than in
fields planted after long fallow or after secondary forest. Host plants such as Dioscorea spp.
(Dioscoreaceae), Aframomun daniellii (Zingiberaceae), Costus afer (Costaceae), Haummania
danckelmanniana (Zingiberaceae), and particularly volunteer cassava were more common
in short fallow vegetation compared with long fallow and forest vegetation, and apparently
served as a reservoir for S. vayssierei infesting cassava fields planted after short fallow. More-
over, scale abundance in cassava fields was positively related to the degree of disturbed forest
cover, and to the abundance of a closely associated ant, Anoplolepis tenella (Santchi). This ant
is vital for scale survival and dispersal; it removes scale secretions (honeydew) and thus saves
the scale from drowning in its own secretions, probably protects the scale from its natural
enemies, and carries the mobile stage of the scale to new plants.
Several ongoing and planned studies are designed to develop a fundamental understand-
ing of ARTS and A. tenella ecology and to develop sustainable tactics for reducing scale
infestations on cassava and other economically important host plants. The studies include
(1) the role of A. tenella in the survival and dispersal of the scale, (2) cast structure, nest and
colony size, diet breadth, and habitat requirements for A. tenella, (3) ARTS response to vari-
ous environmental regimes, (4) biodiversity (molecular and morphological) of ARTS and A.
tenella, (5) identification and characterization of endosymbionts associated with ARTS and
A. tenella and their effects on ant–scale interactions, (6) effect of scale infestations on cas-
sava growth and its root yield, (7) identification of scale-resistant cassava germplasm and its
deployment in scale management, (8) identification and characterization of natural enemies
associated with the scale under different vegetation management systems, and (9) farmer
participatory evaluation and implementation of promising scale control tactics. Results of
some of the ongoing studies will be highlighted.
Biological Control of The Banana Weevil in Africa
Caroline Nankinga, Clifford S. Gold, and Bjoern Niere
Development of biological control of the banana weevil in Africa has depended mainly
on microbial control and arthropod natural enemies. Potential microbial control strate-
gies include the use of the entomopathogen Beauveria bassiana, endophytes, and Bacillus
thuringensis. Research on B. bassiana has involved isolation and characterization, screening
and pathogenicity testing, evaluation of mass production and delivery systems, and testing
of different delivery systems under a range of agroecological conditions. Various strains of B.
bassiana have been isolated from soil and insects hosts in Uganda, Kenya, South Africa, and
Cameroon. Many of these can cause 40–100% mortality in two weeks. In Uganda, a number
of candidate B. bassiana isolates have shown good growth and spore production on locally
available substrates such as rice, cracked maize, and maize bran. Field evaluation of possible
delivery systems of B. bassiana were conducted in Uganda and Ghana and showed that applica-
tion of the entomopathogenic fungi with planting material, pseudostem traps, or soil around
the banana plants can be used to infect banana weevils in the field and reduce damage to the
plant. These studies have demonstrated that good potential exists for the use of B. bassiana
as a microbial control agent and that it would fit well with the broad IPM context being
developed for the banana weevil. Further research is being undertaken to integrate B. bassiana
with other banana weevil IPM options, such as use of semiochemical-based traps and also
the development of economically viable delivery systems that will overcome the problems
associated with field fungal efficacy, persistence, and disease transmission. Current efforts
are also involving the use of endophytic fungi.
Biological control of the banana weevil with arthropod natural enemies may also be
possible. Searches for parasitoids within the weevil’s area of origin in Indonesia were unsuc-
cessful, although the predatory histerid Plaesisus javanus may offer some possibilities. Earlier
studies in Kenya showed that the potential for controlling banana weevil using coleopteran
and dermapteran predators was limited. The control potential of myrmicine ants is currently
under study in Uganda.
Flying Together: Geminiviruses and The Whitefly
Cassava mosaic virus disease (CMD) has been known in Africa for more than a century,
and the whitefly, Bemisia tabaci, has been recognized as the vector of the cassava mosaic
geminiviruses (CMGs) causing this disease for almost as long. CMD occurs throughout
cassava growing areas of Africa, affects roughly half of the continent’s cassava plants, and
causes production losses in excess of US$1200 million annually. The 1990s, however, saw a
dramatic change in the aggressiveness and impact of the disease in East Africa. First reports
of this change came from north central Uganda, where the effects were so devastating that
many farmers abandoned the crop altogether. During the decade, the “CMD pandemic” was
recorded across a large swathe of East and Central Africa, including western Kenya, south-
ern Sudan, northwestern Tanzania, Rwanda, northern and western Democratic Republic of
Congo, and Congo Brazzaville. In each case, there was a rapid spread of unusually severe
CMD, propagated by superabundant populations of B. tabaci. Associated with the severe
CMD was a novel recombinant CMG, East Africa cassava mosaic virus-Uganda (EACMV-
UG), and the severest symptoms occurred where this was present in mixed infection with the
previously occurring African cassava mosaic virus (ACMV). The pandemic continues to spread
up to the present day, and most recently affected areas include Burundi and eastern Gabon.
In view of the apparent westward spread of the pandemic through Central Africa, there is
considerable concern about its possible spread into West Africa. Most significantly, Nigeria,
largest producer of cassava in Africa and the world, appears to be under imminent threat.
Already, mixed EACMV+ACMV infections have been shown to occur commonly throughout
West Africa, and evidence from Nigeria suggests that they are increasing in frequency.
In this paper, an assessment is made of the key parameters that determine the epidemi-
ology of CMD. These include: incidence and severity of CMD, balance between cutting
and whitefly-borne infection, virus species present, and whitefly abundance. CMD survey
data have been analyzed for 16 recently surveyed countries which together account for over
90% of the continent’s cassava production. GIS analysis of the epidemiological parameters
listed has been used to develop an “epidemic index” for each of the regions surveyed. Index
values are developed on a scale of 5 (lowest) to 15 (highest) and provide a measure of the
degree of the CMD epidemic from benign to acute. Regions with an index of 11 or above
are considered to be acute epidemic zones and regions neighboring acute epidemic zones are
identified as threatened zones. This analysis provides a means of making an overall assess-
ment of the threat posed by CMD in different parts of the cassava growing belt of Africa.
The preliminary conclusion is that while the primary CMD “hot zone” lies in the Great
Lakes region of East/Central Africa, other areas where epidemics are likely to occur include
western Central Africa (including eastern Gabon, southern Cameroon, northern Angola,
and southern Central African Republic), coastal East Africa, and southern Mozambique.
The corollary of these findings is that these zones should be a priority when resources are
allocated for CMD control and cassava germplasm distribution and development. The
proximity of southern Cameroon to Nigeria also means that a preemptive approach to
CMD management in southeastern Nigeria is appropriate, given the scale and continental
significance of Nigeria’s cassava crop.
Project C: Assessing Impact, Formulating Policy Options, and
The aim of Project C is the generation and application of knowledge to improve the efficiency,
equity, and sustainability of food production and marketing systems. This project applies
the analytical skills of IITA economists, sociologists, information specialists, GIS analysts,
and anthropologists in collaborative experiential learning processes with other agricultural
scientists from national social and economic research institutes, agricultural extension services
and NGOs. It is focused on the following outputs:
1. Identification and prioritization in close association with farmers’ livelihood strategies,
of the crop breeding, socioeconomic, and crop and resource management requirements
for enhancing productivity and sustainability at the field, farm, and landscape levels.
2. Analysis of socioeconomic policies, social organizations, and market institutions affect-
ing the functioning of crop and crop–livestock systems and input–output markets.
3. Agricultural strategies and innovations for improving health, nutrition and gender
outcomes within rural households.
4. Support systems and market innovations for the enhanced and equitable commercial-
ization of African agriculture.
5. Methodologies and strategies for scaling up and scaling out of “best-bet” technologies.
6. Documentation of the impact on rural and urban poverty and the environment of
research for development by IITA and its partners.
• Development of Strategies to Promote Farmer Utilization of Herbaceous Legumes for
Natural Resource Management. A constraint assessment and farmer evaluation of
herbaceous legume options for crop-livestock integration in the moist savanna of
southern Bénin and the dry northern Guinea savanna (NGS) of Nigeria were
completed in eight villages characterized by differing levels of land endowments
and market access. Overall, farmers in both sites were most enthusiastic about
high-yielding (grain and fodder) groundnut varieties while dual-purpose soybean
was most adopted in NGS villages with good market access. Dual-purpose cowpea was
widely used in all NGS villages but farmers in Bénin were not familiar with this crop
and were not in general enthusiastic about growing it. The fallow cover crop Mucuna
sp. was appreciated in Bénin especially for its soil restorative capacities and to a lesser
degree, its ability to suppress Imperata grass. Livestock forage crops were most accepted
in NGS villages where land endowments still permitted fallowing. Where fallow land
was not available, farmers showed no interest in forage legumes by the end of the proj-
ect. Other constraints affecting the uptake of these systems include gandu practices
in NGS which culturally obliges married sons to work on their father’s land, limiting
their opportunities to adopt. A wealth ranking of participating farmers by members
of the community revealed that the majority were richer than the median village
• Resource-Use Efficiency Among Smallholders in Southwestern Nigeria. The efficiency of
resource use among farmers in two communities located in the forest and savanna
zones of southwest Nigeria was evaluated using a stochastic production function
approach. The mean technical efficiency was 75.5% in the forest and 77% in the
savanna. Therefore, there are opportunities for improvement by rearranging input
combinations in the current system even before any technical change is introduced.
• Rural Household Demand for Roots and Tubers in Southwestern Nigeria: an Almost
Ideal Demand System Analysis. Data on household income and expenditure were
collected over two weeks in each quarter of the year and analyzed using the Almost
Ideal Demand System (AIDS) model. Farm production was the main source of
household income (> 60% in both ecologies) and was below the World Bank
poverty line. Food expenditures accounted for 21.5 of total household expenditures
for the forest and 15.5% for the savanna despite a major share of harvest being
used for home consumption. Major root and tuber-based products consumed
include: gari/eba, cassava flour, fufu, amala (yam), cooked yam, pounded yam,
• Economic Gains from Maize Research in West and Central Africa: An Overview. Agricul-
tural research by national and international institutes has contributed to the increase
in maize production and productivity in West and Central Africa over the last three
decades. Yields in the subregion improved by 41% from an average of 858 kg ha-1 in
1970 to about 1207 kg ha-1 in 2000. During the period under review, a large number
of disease-resistant varieties were released; methods for more effective control of pests
and diseases were developed; and institutional capacity and capability of NARS were
greatly strengthened. While producers benefited from higher productivity, agro-
industry and urban consumers in West and Central Africa benefited from lower maize
• The Transect Walk Characterization Method for the Adoption Dynamics of Modern
Varieties. Household-based methods of measuring adoption are very expensive because
of the need to visit many farmers’ fields and record areas, crop occurrence and plant
densities. A transect walk characterization method allowed the estimation of the
acreage planted to IITA cowpea, maize, and soybean in a survey area of more than
40 000 km2 for a survey cost of US$5000. In addition to adoption studies, the
transect walk characterization approach is also useful for benchmarking areas prior
to development interventions, something that is essential for plausible impact
assessment, but rarely done.
• A Participatory Research and Extension (PR&E) Approach to Integrated Striga
hermonthica Control (ISC) in Northern Nigeria. An evaluation found that the
PR&E approach successfully led to improved farmer knowledge of Striga control
options, changes in farmer perceptions, adoption, and adaptation of aspects of the
ISC options, and farmer-to-farmer diffusion. Adoption of an average of 3.5 ISC
options jumped from 19 farmers in three villages to 271 farmers in 16 villages and
hamlets in three seasons. Farmer field school (FSS) type training played a crucial
role in the adoption and diffusion of management practices, while improved germ-
plasm gave the quick benefits necessary to maintain farmer interest and participation.
A DFID-funded project is now building on the work of this project to develop a
PR&A with government-run extension services in Kaduna State in Northern
• Socioeconomic Analysis of Promising Balanced Nutrient Management Systems in
Northern Nigeria. In the northern Guinea savanna, the economic performance of
three improved maize-based cropping systems were evaluated. The first system is
maize + high fertilizer rate, the second is maize + reduced fertilizer rate + animal
manure, and the third is a soybean, maize + fertilizer rotation. Analysis indicated
clearly the importance of the manure cost to profitability. Because there is no
clear-cut choice for any of the improved systems, it is suggested that they should be
promoted as a basket of best-bet options whose use depends on the farmer’s resources
and market prices. Farmers indicated their preferences for treatments with reduced
fertilizer rates as their major constraints are cost of fertilizer, cost of manure, and
tedious planting of soybean.
• Factors Affecting Farm-Specific Production Efficiency in the Savanna Zones of West Africa.
Five hundred and fifty-nine farm households from the Sudan savanna (SS) and north-
ern Guinea savanna (NGS) agroecological zones were studied to examine the factors
affecting production efficiency. Estimation of stochastic frontier production functions
indicated the importance of including ecological and socioeconomic variables in the
model. The overall average efficiency was 76%: 68% in the SS and 86% in the
• The Adoption of Intensive Monocrop Horticulture in Southern Cameroon. Results from
a survey of 208 households in the humid forest zone of southern Cameroon indi-
cate that the average expenditure on agrochemicals by horticultural producers using
intensive monocrop production systems was US$190/ha. A logit model of intensive
monocrop adoption suggests that policymakers interested in intensifying agriculture
should promote horticultural development in areas of higher population density
while increasing investment in rural roads. Cocoa producers were more likely to
have adopted intensive horticulture, suggesting that export crop promotion
indirectly facilitated diversification. Women’s participation was limited to
traditional leafy vegetables and efforts to promote their greater involvement are
• African Traditional Leafy Vegetables (TLVs) and the Urban and Peri-urban Poor.
African leafy vegetables such as Solanum scabrum, Amaranthus spp., and Corchorus
olitorius were found to be vitally important to the rural, urban, and periurban poor
in Central Africa both as a commercial crop and more importantly as a low cost
affordable source of micronutrients in the diet. Consumption studies indicate that
policymakers interested in increasing nutritional outcomes of the poor would do
well to actively promote the greater consumption of TLVs.
• Labor and Land in the Cocoa Sector of West Africa. The chief factors of cocoa produc-
tion are land, labor, and (to a more limited extent) purchased inputs. The largest
source of labor supply for the 1.7 million family-operated cocoa enterprises of West
Africa is the household’s own internal supply of labor. However, as the size of the
cocoa enterprise increases, more contractual labor is employed, either under leasehold
sharecropping tenure arrangements or through the engagement of hired workers
employed either on a task basis or as full time labor engaged for the cocoa production
season. From 1980 to 2000, cocoa production (and labor demand) more than dou-
bled, stimulated by trade liberalization, exchange rate devaluations, and a surplus of
cheap migrant labor from the savanna regions. This rapid increase in labor demand,
particularly in Côte d’Ivoire, has placed pressure on existing labor institutions and led
to instances of abusive child labor practices. Given the pervasiveness of the child labor
issue across all economic sectors, enhancing state institutional capacity for effective
interdiction and intervention of child traffickers should be an immediate concern in
the effort to achieve a long-term solution.
• WARM-NET – West African Regional Market Network Project C in conjunction with
private sector partners from the Sustainable Tree Crops Program submitted a pro-
posal to the USAID West African Regional Program for enhanced food security in
the ECOWAS region. This is to be achieved through greater intraregional agricultural
trade which will be stimulated by trade intelligence services involving the develop-
ment of a regional network of existing market information systems, capacity building
and strengthening of trader associations and producer marketing cooperatives, and
enhanced supply chain management of the cotton and cocoa sectors. The proposal was
one of two selected for the competitive design phase of the project, which is expected to
cost from US$13 m to $20 m and to last from April 2004 to December 2008.
• Market Research for the Development of Commercialized Agriculture in sub-Saharan
Africa. A symposium on strategies for increasing agricultural trade, food security
and rural income through improved access to local, regional, and global markets was
hosted by Project C at the 25th triennal meeting of the International Association of
Agricultural Economists in Durban, South Africa.
Market-Driven Agriculture and Commercialization in Africa
Sub-Saharan Africa has the world’s weakest agricultural performance, including lowest per
capita calorie supply, and lowest trade participation. Future prospects on world markets are
bleak, as the 2002 US farm bill and the 2003 EU CAP reform are unlikely to reduce surplus
pressure and thus will continue to hamper African agricultural exports and finally the com-
mercialization of Africa’s agriculture.
But problems are not only external in origin. Efficiency in African agriculture is low,
processing is poor, and trade is hampered by poorly functioning institutions. Studies have
proved that the removal of collusion, corruption, and poor infrastructure are more effective
in stimulating agricultural trade than lowering tariffs. Public investments in infrastructure
and market information systems are required. Competition must be fostered and institutional
failures rectified. Promising new agrobusinesses are often hampered by poor access to credit
and finance, due to poorly developed capital markets. Increasing rural investment by
combining public and private finance schemes could help foster competition by assisting
new competitors through their “infant years”.
For primary commodity production, structural transformation will be inevitable, as
larger farms can better adopt new technologies and react to market signals. As this structural
transformation proceeds, smaller, less efficient farmers will be unable to compete and will
enter the job market. As part of the structural transformation however, more agroprocessing
jobs have to be created to absorb in part some of the unemployed. Finally: What type of
production can face the future challenges? For farmers in favorable areas, quality and product
innovations are options to be followed. For farmers in risky environments, new technologies
have to aim at sustainable stabilization. Studies in semiarid areas show that input/output
price relations play a lesser role in limiting production, than risk aversion, which keeps
farmers from adopting new technologies. Research has to focus on low-input techniques and
management, rather than call for notoriously inefficient subsidies and regulation.
Rural Livelihood and Poverty Mapping: Contribution to R4D
P. Kormawa, C. Legg, R. Okechukwu, and R. Alabi
Research within the CGIAR centers has been acclaimed to be pro-poor and contributing
to poverty alleviation. However, donors and development investment partners of these
centers, as well as public-sector policies have recently attached greater weight to poverty
alleviation programs supported in developing countries. In consequence, the International
Research Centers have a major objective to contribute to poverty reduction. Because the
poor spend much of their incomes on food and tend to reside in the rural areas, there is an
inverse relationship between the level of investments in agriculture and poverty. However,
because poverty is a complex and multifactorial concept reflecting a low level of well-
being of people, its measurement remains an important technical concern to social
In contributing to poverty measurement and pursuant of setting priority needs for IITA’s
research for development, this study was designed to integrate socioeconomic, biophysical,
and climatic factors and policies with output maps of vulnerability. It also characterizes the
poor; match their livelihood strategies to vulnerable areas. Results are based on a nation-
ally representative survey of over 3200 households in seven States in Nigeria (Kano, Kebbi,
Borno, Kwara, Osun, Akwa Ibom, and Kaduna) and the FCT-Abuja. A multistage sampling
procedure was adopted to select approximately 400 households/state. The survey question-
naire covered questions on household characteristics and employment, food and non-food
expenditure, purchase of items of wealth, labor use, crop production (annuals and perennials),
institutional variables, farm inputs used, and expenditure.
The States were grouped into five development zones (Northwest, Northeast, North-
central, Southwest, South-south). A consumption and expenditure-based welfare indica-
tor (CEI) (total daily per capita consumption and expenditure) was developed for each
household. Using the estimated CEI, households were ranked into quintile and a broad
range of household and employment characteristics. In addition, a basic needs indicator
(BNI) based on nutritional calorie requirement (per capita), and some village-level variables
was estimated. Using the BNI, the rural households are classified into poor and non-poor
by development zone. The households were further disaggregated by livelihood tactics
(agricultural production) to identify who the poor are, where they live, which crops they
produce, and the commodities they consume. Various maps are produced showing village,
household, production, consumption, input, and resource-use patterns and presented by
poverty class and development zone. Major trends from the maps show distinct interactions
between location and welfare of the household. These results suggest that poverty among
rural households is location and agricultural activity-related, thus research for development
and poverty alleviation strategies need to be designed accordingly.
Globalization, African Agriculture, and The Poor
Globalization, the term used to describe the integration of world markets, is having an
increasingly important impact on the livelihood options of the rich and poor across the
world. In terms of growth, the evidence suggests that countries with open, liberal economies
are benefiting most. Highest rates of growth are correlated with new types of “21st century
products” and services, whereas the link between growth and sales of primary agricultural
goods is less impressive. Unfortunately, in this scenario, it is almost inevitable that the rich
become richer and the poor are increasingly marginalized.
Rather than benefiting from the new trading environment, African countries have gen-
erally suffered from falling terms of trade, loss of market share, and increasing reliance on
more costly imports. Political will has been unable to find common strategies to address the
new trade environment and consequently, African countries are not competitive on world
markets, are uncompetitive in regional trade, and are weak domestically. The international
community has recognized some of these difficulties and has developed two trade initia-
tives, AGOA (African Growth and Opportunities Act [United States Government] and
EBA (Everything But Arms agreement [European Union], to assist developing countries in
Africa to overcome them. While these are encouraging, they are not sufficiently utilized or
lucrative to make any differences.
According to recent studies by IFPRI, prospects for growth in Africa that depend
on traditional and nontraditional agricultural sectors are significantly less than those required
to make gains on population growth. Faced with this bleak reality, several Governments in
Africa have outlined a series of arguments at the WTO that aim to provide a higher degree
of protection for developing country markets and at the same time increase access for their
goods into OECD markets, as proposed in the “Development Box”, or “Food Security
Box”. However, the complexity of the arguments and different levels of trading weight,
have made it difficult for countries in Africa to develop a common proposal that is more
than emotionally attractive to OECD countries. Hence, a general frustration about world
trading rules remains.
The effect of globalization on the poor in Africa, combined with other negative fac-
tors such as political fluidity, poor infrastructure, and HIV, is manifest in dimensions of
scale, location, and prospects. Falling terms of trade and lack of market access has reduced
agricultural incomes and contributed significantly to the loss of the middle class; overall
numbers of the poor are increasing. Urban migration has shifted the location of the poor
into urban centers. Prospects for the urban poor are reliant on diminishing public sector
resources and for many, the most attractive options are to trade in imported goods or enter
service industries. Prospects for the rural poor are increasingly dependent upon their ability
to be competitive in local, national, regional, and international markets.
IITA is working with partners to develop strategies for improving the lot of the poor
through better policies, linked to gains in productivity, value addition, and marketing effi-
ciency. This paper seeks to outline the critical problems faced by the African agricultural
sector, the new types of client that are emerging, and the strategies and technologies that
IITA is developing to address the challenges of these target groups. The focus of this paper
will be on understanding the markets, delivering market signals, and becoming sufficiently
organized to respond.
Project D: Promoting Food Security and Income Generation
Through Sustainable Production and Commercialization of
Starchy and Grain Staples in Eastern and Southern Africa
• A rapid rural appraisal was carried out to determine possible interactions between
banana and coffee production and the potentials and constraints of the system.
Results show that marketing constraints impose a constraint to farmers’ revenues in
both banana and coffee systems. The lack of financial and other resources impedes
management of the two crops.
• Market opportunities for Southern Sudan were evaluated. Results show that the most
severe constraint to marketing is the high transport costs that arise from insecurity and
poor infrastructure. Once this constraint is removed, Southern Sudan will have com-
parative advantages in trade for timber, livestock, groundnut, sesame, and Arabic gum.
• The need for rapid dewatering is the second major problem in the production of
High Quality unfermented Cassava Flour (HQCF). A cassava processing equipment
fabricator (Intermech Engineering Ltd) is being technically backstopped to fabricate
a combined grater-press, to perform grating and dewatering operations in a single,
rapid and continuous operation, thereby leading to reduction in labor, time, man-
hour-energy and handling requirements for HQCF production. The output of the
process will contain less moisture than products made by manual pressing, thereby
giving additional advantages in terms of reduction in drying time and total produc-
• An Open Quarantine Facility (OQF) has been established at ARI Kibaha, Tanzania,
into which 430 genotypes with a high potential tolerance to cassava brown streak
disease (CBSD) were introduced from KARI Mtwapa. In a similar unit established
at Nampula, Mozambique, 125 genotypes were introduced. Preliminary observation
indicates that more than 75% show tolerance to the high CBSD pressure in the two
• Twenty-five improved clones selected within the IITA/KARI/EARRNET breed-
ing program at Mtwapa, Kenya, are being evaluated on-farm in the CBSD-affected
coastal lowlands of Kenya. The same clones are undergoing multiplication in Tan-
zania (25) and Mozambique (18) for rapid on-farm farmer participatory evaluation.
In addition, more than 500 highly promising new genotypes selected at ARI Kibaha
are undergoing evaluation at three sites in Tanzania. Crossing blocks have been
established at ARI Kibaha (Tanzania) and ARI Nampula, (Mozambique) to generate
new genotypes that combine resistance/tolerance to CBSD with farmer/consumer
preferred traits, and decipher the genetics of CBSD resistance.
• One hundred yellow-fleshed cassava genotypes that combine disease resistance, good
agronomic characteristics and cooking qualities are being characterized for micro-
nutrient qualities in collaboration with the Jomo Kenyatta University of Agricultural
• The augmented design is increasingly being applied in farmer participatory research
on-farm evaluation of improved cassava germplasm by many national collaborators
in the region. A total of 14, 12, and 8 improved clones have been selected for release
in 2004 by the Kenya, Uganda and Rwanda national programs, respectively. In the
Republic of Congo, 97 out of a total of 117 genotypes introduced were selected and
cloned at Odziba research station for further evaluation. Genotypes 92/277, 92/167,
and 92/ 269 were ranked as good performers in a multilocational trial.
• Eleven secondary triploids with good bunch characteristics and black sigatoka resis-
tance are being multiplied for testing in farmers fields. Six genotypes including Pisang
lilin, SH3217, SH3142, SH3362, Yangambi Km5, and Kikundi are demonstrating
field resistance to Fusarium. Morphological and cytological characterization of new
germplasm from Papua New Guinea has been completed.
• Banana weevils may be aggregated at or near pheromone lures where they may be
infected by Beauveria bassiana. The weevils remain longer at such lures than conven-
tional pseudostem traps, thereby facilitating adherence of B. bassiana spores to the
insects. Infected banana weevils remain active in the field and can infect other weevils.
• Laboratory studies on antibiosis against banana weevil showed that larvae had longer
development periods on resistant clones, but that survivorship and pupal weight
could not be related to the level of banana susceptibility to this pest. This means that
under current rearing methods, laboratory studies cannot substitute for field evalua-
tions in screening germplasm. Larval developmental rate, survivorship, and size were
all lower on pseudostems than on corms.
• Chopping and removal of crop residues in established farmers’ fields lowered banana
weevil populations and damage. However, effects are not necessarily realized imme-
diately. In small plots, for example, removal of residues initially increased damage to
growing plants and reduced the numbers of banana weevil natural enemies. Covering
harvested corms with soil reduced damage in the wet but not in the dry season.
• Studies conducted on reproductive fitness and pathogenicity on Musa germplasm
of four Radopholus similis populations from four locations (Namulonge, Mbarara,
Ikulwe, and Mukono) in Uganda showed that the population from Mbarara had a
higher reproductive and pathogenic potential compared to the other populations.
This population also managed to break the resistance of Pisang Jari Buaya, world-
wide known to be resistant against R. similis. The IITA hybrid, TMB2x 9128-3,
showed resistance against the four populations. Two secondary triploids derived
from East African highland banana have been identified with resistance against
Radopholus similis using the individual root inoculation method. Histochemical
experiments carried out to study mechanisms of resistance to nematodes in Musa
showed resistant cultivars had an increased number in phenolic cells after
• A diagnostic survey conducted in February 2003 provided a comprehensive and
detailed assessment of the status of cassava mosaic virus disease (CMD) in the
Republic of Congo. CMD incidence was generally high, averaging 86.2% compared
to 80.3% for 2002. The greatest disease severity was observed in Niari Region in the
south and Cuvette Ouest Region in the north. EACMV-UG2 was shown to occur
virtually throughout the country, commonly in dual infections with ACMV. The
high incidence of cutting-infected plants (81.7%), relatively low incidence of white-
fly-borne infection and wide distribution of EACMV-UgV or ACMV alone or in
combination suggest that the CMD pandemic affected the country some years
back, and that the areas sampled are currently in a stable postepidemic phase.
• Highly accurate soil sampling procedures designed to detect changes in soil
properties were promoted in training courses held at the Yaoundé, Kano, and
Ibadan stations, and implemented at research sites in Tanzania, Mozambique,
Uganda, and Kenya.
• A soil spreadsheet to perform the complex calculations associated with the sampling
procedures to detect soil changes has been developed and distributed.
• Soil analytical laboratory facilities have fully implemented advanced quality control
procedures that eliminate systematic error and greatly reduce random error.
• Three on-station cassava soil fertility trials were installed in Namulonge, Uganda,
and Alupe, Kenya. Preliminary results showed that improved cassava varieties did
not compete more efficiently than local varieties in intercropping systems with beans
and that fertilizer use did not significantly increase plant height of five local and six
improved varieties during the first six months of the growing cycle.
• National Stakeholders’ meetings were held in each of the 5 participating countries
(Madagascar, Mozambique, Tanzania, Uganda and Zambia) for the CFC-funded
small-scale cassava processing and vertical integration of the cassava subsector in
Southern and Eastern Africa. A consolidated work plan and budgets for Year 1 have
• Four scientists from the Republic of Congo were trained in monitoring, sampling
techniques, and virus diagnostic at ESARC. An in-country training course on root
crops production and CMD management was organized in Brazzaville for 30 techni-
cians, while 500 farmers were trained in CMD management in four regions. A SAS/
GIS course for 25 participants was organized at IITA/ESARC from 15 September to
1 October 2003.
• The project on accelerated multiplication and distribution of healthy planting materi-
als of the best high-yielding varieties of cassava and sweetpotato in Mozambique has
assembled 124 partners to mitigate the adverse effects of the floods and drought on
food crop production. The project has established 51 ha of sweetpotato, 253 ha of
cassava, and distributed planting material to about 434 000 families. It promoted
the utilization and agroprocessing of both crops using improved tools and machines.
This resulted in the cultivation of orange-fleshed sweet potato as a means to reduce
the risk of vitamin A deficiency countrywide. Several training workshops have been
conducted on production, agroprocessing and the development of collaboration with
private and public agencies.
IPM on East African Banana–Coffee Systems
S. Okech, C. Gold, C. Nankinga, S. Abele, P.M. Wetala, and A. Nambuye
Banana and coffee form the economic base for a large population of Eastern Africa. A partici-
patory rural appraisal (PRA) conducted at seven sites in western and central Uganda showed
that the two crops are grown in various cropping patterns ranging from complete mixtures
to intercrops dominated by one crop to adjacent monocultures. In some cases, banana may
be phased out as a coffee crop matures. East African Highland cooking banana (AAA-EA)
which covers the largest area (about 70%), doubles as a major food at all sites and also as the
leading daily cash income crop at five sites. Other banana types used for brewing (AAA-EA
and ABB) and as dessert (AB and AAA) formed 10 to 20%. Coffee is regarded as providing
a long-term seasonal cash boom.
The yield trends of the two crops over the last 20 years suggest that the systems are
declining. The major production constraints are land scarcity, pests and diseases, declining
soil fertility, and socioeconomic factors (poor marketing options and liquidity to hire labor
and other inputs). Key pests affecting banana include banana weevil (recognized by farmers
at all sites), nematodes (noted by scientists at all sites but recognized by farmers at two sites
only), Fusarium wilt in the exotic dessert type (AAA, AB) and brewing types (ABB). Key
coffee pests and diseases included coffee wilt, coffee mealy bug, scales, coffee berry borer,
and coffee stem borer (reported at one site only). Robusta coffee is the predominant coffee
cultivar at all sites and is very susceptible to coffee wilt. Arabica coffee (resistant to coffee
wilt) was grown at one site only in Mbarara district.
Currently, cultural control is the main IPM option adopted for all the above pest
constraints. These include (i) crop sanitation and clean planting material for banana weevil
and nematodes and (ii) roguing for Fusarium wilt and coffee wilt. There are no clearly defined
management options for other pests.
Banana and coffee mutually benefit each other but also compete with each other for
resources. Banana provides shade and mulch for young coffee (moisture, nutrients) while
coffee provides husks for banana (nutrients) at sites closer to the coffee factories. Farmers
using coffee husks also reported low incidence of banana weevil in their plantations and
hence an additional option for weevil management.
The effect of coffee intercrops on pests and disease incidence in banana was not clearly
understood. Farmers at four sites (central Uganda) reported low weevil incidence in banana-
coffee intercrop while farmers at other sites in Masaka and Mbarara did not notice any
difference. Future studies to understand the effects of a coffee intercrop and use of coffee
husks on banana weevil incidence and management have been planned. The antagonistic
aspects of the system are that: coffee depletes soils while banana throws shade on older coffee
plants. This is currently overcome by adjusting spacing.
Both the economic and agronomic potential, especially of intercropping systems, is not
yet fully exploited. Whether they are grown intercropped with each other or cultivated on
pure stands, banana and coffee have many economic and agronomic relationships, both
positive and negative. These relationships have to be further developed and improved. With
regard to the economics of the system and its relationship to IPM, it was noted that liquidity
and food security play an important role in economic decision-making. Lack of liquidity
among farmers leads to poor crop management, including pest management. More attention
was given to banana because of food security.
Status of Host Plant Resistance Breeding to Nematodes in
Carine Dochez, Jim Whyte, Michael Pillay, and Abdou Tenkouano
The East African Highland banana (EAHB) is the most important staple crop in the East
African Great Lakes Region. However, nematodes are a serious constraint to sustainable Musa
production. Radopholus similis is commonly known as the most damaging nematode species,
causing severe yield losses. The use of host plant resistance provides promising prospects as
a basis towards nematode management and improved banana production.
All five clone sets covering the East African Highland bananas, including cooking and
beer types, are susceptible to R. similis. Crosses between EAHB and Calcutta 4, a diploid
wild banana with (partial) resistance against R. similis, have earlier resulted in resistant
tetraploid hybrids. This year, the first secondary triploids with resistance against R. similis
have been identified.
Different pathotypes might exist within a nematode species, and the resistance might
be effective only against some pathotypes, but not all. If the target nematode species has a
high level of genetic variability, the durability of the resistance might be affected. There-
fore, populations of different locations within Uganda (Namulonge, Mbarara, Ikulwe, and
Mukono) were collected and cultured monoxenically on carrot discs. Reproductive fitness
on carrot discs and pathogenic potential on host plants have been compared. The popula-
tion from Mbarara showed a higher reproductive and pathogenic potential compared to the
other populations. This population also managed to break through the resistance of Pisang
Jari Buaya, known worldwide to be resistant against R. similis. The diploid hybrid TMB2x
9128-3 and Yangambi Km5 showed resistance against the four populations.
Studies on the mechanisms of resistance will help the breeding program to select for a
desired feature. Histochemical experiments were carried out to detect differences in lignin
and phenolic compounds between susceptible and resistant cultivars. Lignin might form a
physical barrier for nematode penetration, i.e., pre-infectional resistance. Formation of phe-
nolic compounds might refer to induced resistance as a response to nematode penetration.
At different times after the inoculation of resistant and susceptible cultivars, root sections
were taken from near the corm, in the middle of the root, and at the root tip. Detection of
lignin was done using safranine with counter stain fast green. Phenolic cells were detected
using ferric chloride. An increased number of phenolic cells were observed after nema-
tode inoculation in resistant cultivars. The highest number of phenolic compounds was
observed in the resistant diploid hybrid TMB2x 9128-3 and Yangambi Km5, both showing
resistance against the four R. similis populations.
Multiplication and Distribution of Superior Planting Materials
and Postharvest Intervention Activities for Cassava and Sweet-
potato in Mozambique: A Food Security Enhancement Activity
Maria Isabel Andrade
This project was initiated with a specific aim of mitigating the adverse effects of the
floods/drought on food crop production in various districts of the country. Its objective
was to increase food supplies through farmer production of superior varieties of cassava
and sweetpotato. This would be through using rapidly multiplied and distributed healthy
planting materials of the best-bet varieties.
The project targets 500 000 farming households, each to receive 200 plantable vines
of sweetpotato and 100 plantable stems of cassava. Some 93 selected districts of the
141 districts of the country in 9 of the 10 provinces are the operational areas to benefit
directly from this project, as regards the multiplication and distribution of healthy improved
planting materials of both crops.
For two years (March 2001–March 2003), USAID supported Mozambique through
this IITA/SARRNET executed project with 84.4% of the total of US$2 252 400. In-kind
contributions from Mozambique, IITA, and CIP were 4.6, 8.3, and 2.7% of US$2 252 400,
respectively. From April 2003 to March 2004, the Government of Mozambique is support-
ing the program with US$1 000 000.
There are several significant achievements that are already visible to indicate
ongoing progress in the different aspects of the project. The project has made impressive
progress and has provoked awareness on the use of cassava and sweetpotato to meet the
hope of producing more food with little farmer input. Over two years, it has been possible
to recruit staff and motivate them through training. The 12 project staff member were then
equipped to engage in widespread partnerships with over 120 institutions and agencies as well
as NGOs. Together, they planned and executed operations in the nursery, kitchen/laboratory,
field, schools, churches, and at the farm-level towards the multiplication and distribution of
the best-bet clones of cassava and sweetpotato planting materials for onward use by farmers.
In addition, much information on postharvest issues has been accumulated.
In summary, the project has, among other things:
• set-up a functioning office and food laboratory/kitchen at INIA, Maputo.
• assembled some 124 partners who understand their role in the objective of the
An accelerated multiplication and distribution of healthy planting
materials of the best high yielding varieties of cassava and sweetpo-
tato in Mozambique as a drought and flood mitigation activity
The development of a network of a host of knowledgeable partners has been achieved.
These championed the distribution to farmers of materials that had been produced from
the various multiplication plots after harvest.
• established a well-coordinated network of fields of the Project and Partners
now covering 51.4 ha of conventional multiplication plots of sweetpotato
and 253 ha of multiplication plots of cassava in different districts across the
• distributed sweetpotato and cassava planting materials to 433 735 families
across the country.
• widely and successfully promoted the utilization and agroprocessing of both
crops by demonstrating the use of improved tools and machines in workshops
and field days.
• widely and successfully promoted the cultivation and use of orange-fleshed
sweetpotato as means to reduce the risk of vitamin A deficiency countrywide.
• successfully promoted the utilization of orange-fleshed sweetpotato and
the nutritional concept to students of primary level school in Marracuene,
• conducted several training workshops on production, agroprocessing, market
products development in concert with private and public agencies. Group-
training courses, attachments, promotional activities, development of training
materials, and personnel development on cassava and sweetpotato were
undertaken at different sites. These were done with project partners on
themes related to the multiplication and distribution of planting materials, as
well as processing and utilization of cassava and sweetpotato. These activities
have exposed participants to new knowledge resulting in better management
of activities for the production and utilization of both crops.
• used student in project research to achieve project goals and also benefited
the students as trainees. During the two years (2001–2003), seven students
completed their project research. These were students of Universidade Eduardo
Mondlane, Maputo, Mozambique, in different sessions.
• established a series of cassava and sweetpotato variety trials at several locations
in the major agroecological zones with the aim of selecting the best adapted
Also, to encourage a more commercialized approach to the utilization of these crops and to
record the current status of the production, processing and marketing of cassava and sweetpotato
in Mozambique, a nation-wide collection of cassava and sweetpotato baseline data to examine
patterns of preference and practices has been carried out and the report has been written. The
survey team comprised SARRNET staff as well as 65 partners. The survey collected data and
information on selected aspects of production, agroprocessing, utilization and marketing themes
for cassava and sweetpotato. Between 200 and 400 completed questionnaires were received
for each of these three aspects from all the 43 districts in five provinces out of the 141 districts
of the 10 provinces of Mozambique. A total of 1476 people were interviewed. The major
findings are presented below:
• Cassava is the second most important crop of Mozambique after maize
generally but first in some districts. Its leaves are consumed nation-wide
and are on sale in most markets.
• Sweetpotato is the third most important crop in Mozambique after maize
and cassava and is found in most districts as a crop for carbohydrate and
vitamin rich roots and mineral-rich leaves.
• Both crops are important for food to many people in the five provinces
and also in other provinces that are neighbors to the one surveyed.
• Both crops are important for generating household income.
• The crops are consumed frequently in the household food or diet schedules each
week so that they are good commodities for alleviating hunger in cultivating,
processing, and marketing households.
• Inadequate farm tools and lack of knowledge about the varieties, and/or
techniques for processing and conservation hinder the full realization of the
potential of these crops in Mozambique.
• The marketing of both crops and their varied products is very common but
that no packaging for appeal or longer storage and conservation is being
practiced. The need to process, package, and make products apart form
the basic and traditional forms of use should be given more priority in
research and development.
• As the statistics on the production of both crops are not reflective of the
changes happening, there is need to refine the data collection and measure-
ment systems for these crops. A nationwide survey was carried out to
estimate the yield of cassava and sweetpotato and the impact of orange-
fleshed sweetpotato and improved cassava clones distributed.
The search for clones tolerant/resistant to cassava brown streak disease is an
ongoing activity. There is need to refine the data collection on various pests and disease
of cassava and sweetpotato; therefore, two nationwide surveys were carried out to record
the various pests and disease problems for these two crops and to estimate the yield loss
Marketing Cost of Cassava and Sweetpotato in Southern
Africa: The Case of Malawi, Tanzania, and Zambia
M.A.R. Phiri, A.E. Temu, D.A. Nyange, F. Mashamba, S. Tembo, P. Ewell,
S. Kolijn, S. Jumbo, and N.M. Mahungu
Subsector analysis studies were conducted in Malawi, Tanzania, and Zambia to under-
stand the structure and performance of cassava and sweetpotato markets in these countries
and draw inferences for Southern Africa. The surveys were carried out in major cassava
and sweetpotato production, consumption, and marketing areas between 2000
and 2002. Data were collected at the level of farm, rural market, wholesalers, transporters,
retailers, and industrial processors, covering all marketing aspects including marketing
opportunities for processed products. The surveys comprised three phases: literature review,
qualitative assessments, and quantitative studies. A total of 730 producers, 544 traders,
and 790 consumers were interviewed using structured questionnaires and participatory
The studies showed that there had been significant increases in production and
consumption of cassava and sweetpotato in the region in the recent years with production
expanding even in nontraditional growing areas where 90% of the farmers sold their
cassava, implying that cassava had become an important cash crop in the region. For more
than 70% of the farmers, food and cash were the major reasons for growing cassava and
Consumption of cassava/sweetpotato is expanding mainly as a substitute for products
taken during breakfast. The major form of consumption reported was fresh boiled roots.
Preferred varieties are those with that had a good (sweet) taste, were fast cooking and had
high dry matter content, all related to consumption of the fresh product.
Players in the cassava/sweetpotato marketing chain: producers, traders (middlemen/
wholesalers, retailers), transporters and consumers mainly rely on “social networks” and
personal observations for marketing information. Pricing of cassava/sweetpotato is subjective
with a certain level of bargaining for both quantities and price; however, traders, especially
middlemen have an upper hand in price determination. No clear standards are set but
root size, grade, farm gate-price, and to a lesser extent, variety, freshness, and color play
important roles in pricing, especially at retail markets. Transport costs constitute the major
costs incurred by traders.
There are a number of industries using cassava products as raw materials; however, little
cassava penetrates the industries despite the fact that demand for industrial use has been
increasing. Producers and traders mainly target the fresh cassava/sweetpotato market rather
than the processing industries. It was found out that the fresh market is more lucrative than
industry. In addition, the linkage between industrial processors and producers is very weak
and in most areas, it is nonexistent. Little processing of cassava was reported among players
with most of it being done to change the form in which the product is consumed and to
increase shelf life. Processing was mostly reported in areas where cassava is grown as a staple
food. Processing methods reported were mainly rudimentary involving peeling, fermenting,
Fostering technological advances in domestic processing and strong linkages between
producers and the industry would enhance the consumption and utilization of cassava/
sweetpotato products. The supply of timely and reliable market information as well as
establishing grades and standards would facilitate the marketing process.
Project E—A Future Through Farming—Enhancing Livelihoods,
Improving The Resource-Base and Protecting The Environ-
ment Through Starchy Staples, Peri-Urban and Tree Crop
Systems of The Humid and Subhumid Zones of WCA Africa
Project E staff force increased with several new appointments in Cameroon (5), Côte d’Ivoire
(1), the Democratic Republic of Congo (2), Ghana (1), and Nigeria (2) with projected arrival
of at least 4 more people (essentially in Nigeria). Further infrastructure development has
taken place in Cameroon to support seed multiplication and plant health investigations.
Also, project structure has been revised with the number of outputs reduced from seven to
Output 1–Productive Plantain Systems
Boiling water treatment of planting materials and fertilizer application jointly reduce
nematode infestation, hasten plant growth, and improve the yield of plantain in Cameroon.
First bunches were harvested as early as 11 months after planting (MAP) from boiling water
treated and fertilized plots which indeed bore more flowered plants at 18 MAP and fewer
uprooted plants than plots not subjected to both treatments. Thus, treatment interacted
with fertilizer application such that the boiling water treatment combined with fertilizer
produced nearly three times more yield than the fertilized option without the boiling
Leguminous cover crops reduce nematode population densities in the soil. Planting
Pueraria phaseoloides or Flemingia macrophylla reduced nematode population densities in
the soil within one year after planting compared to a hot pepper crop and a control left to
volunteer regrowth. This suggests that leguminous species can provide a sustainable means
of controlling nematodes in farmers’ fields.
Improved hybrids raise farmers’ income and boost the yield of landraces in varietal mix-
tures in Nigeria. Higher harvest frequency and bunch yields for the hybrids (18.0 kg) relative
to the landraces (7.4 kg), were recorded with corresponding cash income of N10 000 for
hybrids and N7000 for landraces. The average bunch weight of landraces increased from 6.1
kg when planted sole to 8.4 kg when planted in mixture with hybrids. Adoption prospects
of the new varieties is very high as the yields of contact farmers increased by an average 50%
on land cropped with hybrids and each distributed suckers to 18 new farmers.
Output 2–Intensified Cassava Systems
IITA launches several integrated projects to pre-empt virulent forms of the cassava mosaic
virus while fostering cassava-based agroenterprise development in West and Central Africa.
An unusually severe CMD outbreak, caused by a recombinant hybrid of the East African
cassava mosaic virus (EACMV) and African cassava mosaic virus (ACMV), designated as the
Ugandan variant (EACMV-Ug), has been spreading from Uganda, through East Africa and
westwards into Central Africa. Pre-emptive action is being taken to deploy cassava cultivars
with durable resistance to this new threat in order to prevent a repetition of the devastation
that occurred in Uganda in the 1990s. Multidonor-sponsored interventions implemented
via public–private partnerships have been launched in the Democratic Republic of Congo
and Nigeria, based on an integrated cassava commodity chain approach linking production
to markets for increased food security and income generation.
Output 3–Sustainable Yam Systems
Ethephone breaks dormancy and induces germination of yam tubers, opening prospects
for off-season yam cultivation. Ethephone was applied to induce the sprouting of dormant
tubers of white Guinea yam (D. rotundata var TDr 93-31) and water yam (D. alata var
TDa 95/00328). Dormancy-released tubers of both varieties obtained in January 2003 were
planted in farmers’ fields (Bida, Niger State, Nigeria), producing new mature tubers that were
harvested in early September 2003. This provides opportunities for developing off-season
yam production systems.
Visual symptoms of nutrient deficiency established to facilitate field diagnosis. Symptoms
related to deficiencies in the nutrition of D. alata and D. rotundata were studied in a screen
house using water culture. The symptoms of deficiency of major elements were visible on
plants of both species. The omission of minor elements Fe, B, and Mo produced characteristic
symptoms on the leaves of D. rotundata, but D. alata showed symptoms only in response
to Fe deficiency. The nutrient levels in the leaves of the deficient yam plants compared to
the control support the diagnostic value of the visual symptoms. These would be useful for
diagnosis in the field.
End-use qualities and food value attributes determine yam price. A study of the implicit
market values for yam tuber attributes in two consumption centers in Togo shows that prices
were differentiated across yam species and varieties within species, reflecting different end-use
qualities and food value attributes. Producers and retailers can derive a price premium of
4 to 23 CFA francs/kg of fresh tuber by storing yam instead of selling it at harvest. Carot-
enoids that are source of the yellow coloring in tuber flesh and precursors of vitamin A are
valued by 11 francs/kg over the white color which is more common in the markets. There
are premiums for short growth cycle and tuber size, reflecting the possibility that farmers
could tap into high price markets by growing early-maturing varieties and managing crop
production toward harvesting big tubers.
Modified rapid yam propagation techniques subtend commercial seed production in
Nigeria. An analysis of the seed yam sector in Nigeria showed the presence of localized hubs
of farmers specializing in commercial seed production. In some areas, the small-scale farmers
have been able to expand seed yam production from 0.1 ha to 0.25 ha while a few progres-
sive farmers planted up to 2 ha using modified rapid yam propagation techniques. Thus,
there is a potential for promoting small private seed yam businesses within communities to
assure the multiplication and distribution of newly released yam varieties, instead of relying
solely on public/national services.
Output 4–Multi-Product Tree Crop Systems
Dacryodes edulis, Ricinodendron heudelotii and Terminalia ivorensis grow best in combination
with plantain, the “least-shade treatment”, in a multistrata agroforest established on short
fallow land. The survival of D. edulis was highest under Inga (66%) and plantain (54%).
Survival of T. ivorensis was enhanced by cooking banana (74%), plantain (71%), and Inga
(69%). By June 2003, T. ivorensis was significantly taller, with greatest mean diameter (61 mm
compared with 46, mm in Inga, 45 mm in cooking banana, and 42 mm in bush treatments,
and higher canopy cover and branching level in the plantain shade treatment than in the
other treatments. D. edulis was tallest (2.76 m) in the plantain treatment, compared with
1.97 m, 2.02 m, and 2.06 m in inga, cooking banana, and bush treatments. Corresponding
stem diameters were 50 mm in plantain compared with 32 mm in Inga, 33 mm in cooking
banana, and 31 in bush treatments. R. heudelotii had the greatest stem diameter (67 mm)
in the plantain treatment compared with 44 mm in Inga, 40 mm in cooking banana, and
61 mm in bush treatments.
Sanitation may not replace fungicide application against blackpod disease to sustain
cocoa yields. From January to September 2003, the blackpod disease was shown to reduce
dry bean mass by 189 kg ha-1 in untreated plots, 71 kg ha-1 in plots subjected to low
fungicide application and 37 kg ha-1 in plots with high fungicide application. Indeed, without
spraying, yield losses to blackpod disease approach 100%, even with stringent phytosanitary
harvests and complete removal of infected material from the cocoa field (Fig.1). Furthermore,
removal of diseased pods is a significant nutrient export, which may have negative long-term
consequences on sustainability.
Output 5–Market-oriented Peri-Urban Crop and Livestock Systems
African traditional leafy vegetables (TLV) provide essential nutrients and cash income to
the urban and peri-urban poor. TLVs are normal goods that contribute a significant share
of essential nutrients for the urban poor in Cameroon. Field and market surveys estimated
that over 32 000 households were engaged in producing and marketing TLVs under
readily accessible entry conditions. Three production styles largely operated by women were
identified: an intensive system within the urban limits, a semi-intensive style in the urban
periphery and an extensive style also in the urban periphery. Successful in situ conservation
Dry bean yield kg ha–1
08-01 10-01 12-01 02-02 04-02 06-02 08-02 10-02 12-02 02-03 04-03 06-03 08-03 10-03 12-03
Figure 1. High or low intensity fungicide application against the blackpod disease
enhances cocoa yield over no application in Cameroon.
will require research to improve the productivity of TLV cropping systems and media efforts
to promote their use.
Leguminous species integrated into intensive peri-urban maize and cassava systems can
provide additional food and cash and serve for partial N-fertilizer substitution, but do not
enhance soil conservation. Yield effects of legumes on maize grain yields are mostly insig-
nificant after 1 or 2 years of cropping, but a yield-stabilizing trend of legume fallows occurs
after 4–5 years of continuous cropping. N-fertilizer replacement values of 0–148 kg N/ha
have been found for different legume species. This is less than the 187 kg N ha-1 required to
obtain maize yields of 4 t/ha-1, which only a few herbaceous legume species can achieve in
the forest margins as can natural fallows topped with 40–70 kg N ha-1 of urea.
Soil conservation of legume fallows has not been found so far. Grain legumes
have far lower potential for soil conservation and fertilizer substitution, but they may
offer better adoption prospects for farmers, with experimental land equivalent ratios
of 1.1–1.3 when intercropped with maize. With the exception of Flemingia macrophylla
alley-cropped with cassava, most leguminous species failed to have a positive impact on
cassava root yields.
Output 6–Integrated Farm and Landscape Management Options
Participatory research and extension approaches were implemented in the humid savanna
to promote improved Imperata management technologies and increase adoption prospects
by small-scale farmers. Sixty extension agents were trained in general agronomy, Imperata
biology and management, sprayer calibration and safe herbicide application, and participa-
tory extension methods. Around 1000 farmers affected by speargrass in yam, cassava, and
maize production systems were also mobilized. Labor was identified as the major hindrance
for improving farmers’ production systems in speargrass-dominated sites since tripling labor
price reduced treatment benefits by 38% in contrast to only 3% benefit reduction associated
with tripling the price of glyphosate.
Output 7–Strengthening Institutions and Outreach
Côte d’Ivoire starts its own Musa breeding program with backstopping from IITA.
The Centre National de Recherche Agronomique (CNRA) of Côte d’Ivoire becomes
the first NARS in WCA to initiate a plantain breeding program. The first hybrid
Musa plants derived from crosses involving parental lines from IITA were regenerated
using a seed germination protocol developed by IITA and field established at Abbe
(Azaguié) station in Côte d’Ivoire. Ghana establishes a delivery system for healthy
improved Musa germplasm with field tolerance to Banana streak virus and resistance
to black sigatoka disease. This project began in 1999 and was concluded in 2003
with the establishment of a decentralized system of nurseries for both improved hybrids
and preferred local landraces across Ghana. Monthly farmer field schools are
now routinely carried out with farmer groups established around secondary nurseries.
Thus, 500 farmers have been exposed to new technologies for rapid multiplication and
effective management of banana/plantain while 300 farmers are now involved with newly
introduced Musa hybrids.
Parents Seed set Seed germination (%)
Long Tavoy PITA 2 36 11.1
PITA 14 21 9.5
Other 83 0.0
Selangor CRBP 100 916 3.5
Lacknau 217 11.5
PITA 8 622 14.0
PITA 17 201 15.9
Other 327 0.0
Yangambi Km 5 CRBP 100 34 35.3
Other 135 0.0
Total 2,592 7.5
Nigeria releases four improved yam varieties from IITA while Ghana moves to the
final stages for release of three other varieties. Four improved yam varieties were released
for cultivation in Nigeria following conclusive tests in partnership with the National Root
Crops Research Institute. The released varieties include TDr 89/01213, TDr 89/02665,
TDr 89/01438, and TDr 95/01924. Meanwhile, the Crops Research Institute in Ghana has
planted three IITA-derived clones (TDr 89/02665, TDr 89/02660, and TDr 98/02977) for
inspection by the National Varietal Release Committee.
Region Mother nursery Secondary nursery Satellite nursery
Ashanti Fumesua Kyekyebiasi 9 farmers
Brong Ahafo Goaso –
Central Assin Fosu Assin Bungalow 6 farmers
Eastern Kade Asamankese 10 farmers
Volta Kpandu –
Jasikan 15 farmers
Western Juaboso 10 farmers
The STCP Action Plan founded on a long-term private–public partnership to ensure
a sustainable production and stable supply of quality tree crop products moved into full
implementation of its 3-year program, focusing initially on cocoa and cashew systems. Pilot
projects have now been set up in five countries (Cameroon, Côte d’Ivoire, Ghana, Guinea,
Nigeria) in which farmers are being trained in improved production technologies, farmer
organizations are being strengthened to provide efficient key services to their members, mar-
keting and information systems are being tested for their ability to increase farmer income,
and rural communities are being sensitized on important social issues such as the use of child
labor, HIV/AIDS, and farm safety. A farmer field school curriculum on cocoa (FFS-CC)
has been developed, including integrated pest management strategies, rehabilitation of old
cocoa farms, and postharvest quality management, as well as child labor issues potentially
associated with cocoa production. About 90 facilitators selected from farmer organizations
and 40 from public extension services have been trained in four countries for implement-
ing the FFS-CC. Over 160 schools have been established through which more than 4000
farmers are being trained. The level of enthusiasm and demand for FFSs is extremely high
among the rural community as well as local authorities. Collective sales attracted 5 to
10 % additional revenue for farmers in Cameroon and Nigeria, and 2–10% in Côte d’Ivoire,
depending on the sales strategy, i.e., timing of sale, volume of sale, and the shortening of the
supply chain by selling directly to exporters.
Legumes in The Cropping Systems of The Humid Forest Margins
At present legumes are not well integrated into annual cropping systems in the humid forest
margins of West and Central Africa. These systems are dominated by starchy crops, such
as cassava, cocoyam, and yam as well as by cereals such as maize and rice. The only widely
grown legume is groundnut, which is a component of many subsistence mixed food crop
systems. Its grain and biomass yields on farmers’ fields are generally low.
Objectives of integrating legumes into these systems are: (i) N-fertilizer substitution; (ii)
soil conservation and weed suppression; (iii) food production and cash.
N-fertilizer substitution of legumes has been tested with N-demanding maize in intensive
no-input sequential cropping systems without fallow. Maize is the ideal test crop, because
of the close relationship between total N-uptake and grain yield. Yield effects of legumes
on maize grain yields are scanty and mostly insignificant after 1 or 2 years of cropping.
Longer-term (> 5 years) experiments can show significant differences between short herba-
ceous legume fallows and natural fallows, although not always, highlighting the resilience
of the natural fallow system. However, there is always a yield-stabilizing trend discernible
in favor of legume fallows after 4–5 years of continuous cropping. N-fertilizer replacement
values of 0–148 kg N/ha have been found for different legume species. A yield target of 4
Mg ha-1 of maize grain requires N-accumulation in legume fallows of at least 187 kg N ha-1,
which can be achieved only by a limited number of herbaceous legume species in the forest
margins. However, that yield level can at present also be attained after natural fallows and
40–70 kg N ha-1 of urea.
Legumes as fertilizer substitutes in cassava systems have mostly failed to show significant
effects on crop yield. Herbaceous legumes seem to be unsuited for intercropping with cassava.
Among trees and shrubs, only Flemingia macrophylla, alley-cropped with cassava, showed
positive effects on root yields.
The interest of farmers in benchmark villages to replace natural fallows with leguminous
fallows for green maize production is so far limited, but better targeting of land-constrained
farmers in peri-urban areas should be tested.
Soil conservation of legume fallows has not been found so far. A long-term experiment
showed a trend of considerable loss in nutrient stocks, notably N, regardless of fallow type.
The carbon stock remained unchanged, indicating that leaching was the major reason for
the N-stock decline. Soil-covering spreading legumes apparently cannot prevent leaching.
Grain legumes have far lower potential for soil conservation and fertilizer substitution,
but they are more interesting to farmers. However, the farmers’ lack of familiarity with legume
cropping and food preparation must be addressed in order to increase adoption.
Several grain legume species have been tested. Experiments show that without chemi-
cal fertilizer and pesticides grain yield levels of 0.5–1.5 Mg ha-1 can be achieved with sole
cropped soybean and cowpea, and 0.5–0.6 Mg ha-1 with pigeonpea, and phaseolus beans.
P-fertilizer addition increases soybean grain yields on a range of soils and cowpea grain yields
on P-deficient soils. Nodulation and thus N-fixation of tested soybean cultivars on more
acid soils is a problem.
Testing the integration of these legumes into maize cropping systems has started and
land-equivalent ratios of between 1.1 and 1.3 have been found.
Only legumes with growing periods of ≤ 90 days, such as groundnut, cowpea, and
phaseolus beans are suitable for cassava-based intercropping. Legumes with longer growth
periods, such as soybean and pigeonpea are better sole cropped in sequential systems, because
competition with cassava suppresses both components. However, there is need to further test
cassava cultivars with short growth habits and a high harvest index for such systems.
The effects of these intercropping systems on soil fertility in the region are not yet
Improving Yam Planting Materials and Crop Management
H. Shiwachi, K. Amegbeto, D. Coyne, and R. Asiedu
Cultivation of yam (Dioscorea spp.) provides food and income to over 60 million people in
the tropics, especially in West Africa. Planting material (seed tubers or seed yam) for produc-
tion of ware yam tubers are derived from approximately 25% of the previous year’s harvest
accounting for about 50% of total production cost. The quality of planting material signifi-
cantly influences production, particularly if this is contaminated with pests or pathogens.
Poor quality seed leads to poor germination and consequently patchy growth within the
field. Hence, better awareness and adoption of practices to improve seed health is required.
Apart from the high expense of transporting seed yam, the multiplication ratio for planting
material in the field is low (about 1 : 10) compared, for instance, to some cereals (1 : 300).
Whole seed tubers or tuber sections weighing about 200 g to > 1.0 kg are used for planting
in various cropping systems, but the agroecology and the target market influence the choice
of size of planting material. Additionally, factors such as staking, spacing, planting date, the
size, and type of seed exerts significant influence on crop performance. Planting healthy,
whole seed tubers leads to uniform shoot emergence and crop establishment. Many farmers
obtain seed tubers annually for use as planting material for the subsequent season’s crop,
either from early-maturing varieties of D. rotundata through the “double harvest system”, by
planting small seed setts or by collecting from other farmers. The technique of rapid multi-
plication using small tuber pieces (25 g referred to as minisetts) in field nurseries has been
developed for acceleration of yam propagation. The minisett technique offers opportunities
for producing large quantities of seed yam in relatively small areas. However, constraints to
wide adoption of the technique include unavailability of appropriate fungicides, difficulties
in handling small setts, output of small-sized seed yam, which leads to smaller than pre-
ferred ware tubers, high labor requirement, and limitations in response of some traditional
varieties to the technique. In reality, the minisett technique has been inadequately exploited
and requires greater promotion in a more effective and targeted manner. The technique is
well suited to improving seed health maintenance procedures, especially in areas where yam
cultivation is expanding, where late-maturing varieties dominate, and/or where new variet-
ies have been introduced. Tissue culture offers excellent opportunities for mass production
of healthy yam propagules, through the production of in vitro plantlets and microtubers
in vitro or minitubers in nurseries from certified plantlets. Alternative means of producing
seed tubers include the propagation of yam vine pieces and detached slips. Improvements in
protocols for using such alternative plant parts for propagation could improve viable com-
mercial options for the production of seed tubers. Additional studies on the circumstances
(technology, institutional arrangements, demand, policy) that will enhance the viability of
seed yam production enterprises will greatly complement these efforts.
Managing Resources in The Congo Basin
Valentina Robiglio and Christopher Legg
How can GIS contribute to the development of options and preferences
for the implementation of regional and local strategies? Some examples
for the Congo Basin based on our experience in Cameroon
IITA’s strategy for scaling-up of research outputs from benchmark areas to the Congo Basin
uses Geographic Information Systems (GIS) and is based on the identification of different
levels of biophysical and socioeconomic aggregation. The level of geographical accuracy that
we can target strictly depends on the accessibility and quality of existing datasets and on the
uses for which the information is required.
Generally, for the whole Congo Basin area, IITA maintains a comprehensive spatial
database, including vegetation cover, climate surfaces, hydrography, and satellite imagery.
This spatial data, together with information on population, soils, and transport networks,
can be used at the regional scale (1:2,000,000 to 1:5.000.000) to initially identify broad
intervention domains. Examples are given for the identification of ecozones in the Congo
Basin, and to show that the Humid Forest Benchmark in southern Cameroon is representa-
tive in most respects of the Congo Basin as a whole.
At a finer level, the identification of target areas is an analytical process that requires
information, especially on socioeconomic and infrastructural factors such as the quality of
transport networks that can serve as indicators for the constraints to income generation and
for the access to economic opportunities. Pilot studies in poverty mapping carried out in
Nigeria by IITA serve as examples of what is required in the Congo Basin. Examples are
given for the spatialization of cassava flows in the area of Yaoundé (Cameroon) and for a
market access model in the forest area of the south of Cameroon. Furthermore, zooming into
a finer scale, additional factors can become relevant, e.g., the spatial domain of a resource
management system and the presence of extension services in the area. Examples are given
for three study sites in the forest area of the south of Cameroon.
To ensure that within a project framework, the right technologies are introduced in the
right place and in a way that suits the purpose and the sociological, economic, and extension
environment of the targeted area, all the levels need to be included in the analysis, knowing
that the number of key factors and the degree of accuracy with which they can be expressed
constitute one of the principal restrictions to the accuracy with which a GIS-based strategy
can be effective. The establishment of partnership with local institutions and civil society
groups can allow a preliminary diagnostic selection of the key driving forces in order to better
focus the data collection and GIS management activity. An example is given of the ongoing
spatial inventory of NGOs in Cameroon.
Project F: Improving and Intensifying Cereal-Legume Systems
in The Moist and Dry Savannas of West and Central Africa
The rapid increase in population and consequent pressure for food are driving agriculture
towards greater intensification in West and Central Africa. The long fallow periods have not
only diminished but agriculture has now been pushed on to marginal lands leaving little
or no scope for further expansion in the cultivated area. The bulk of the agriculture in this
region is still based on traditional intercropping systems with low density and little or no
application of fertlizers and chemicals. This leads to a negative balance of nutrients in the
soil and a continuous decline in crop yields which in turn leads to low per capita availability
of food resulting in widespread malnutrition and hunger. This is more pronounced in the
savannas of West and Central Africa where rainfall is low and erratic and soils are predomi-
nantly sandy with low levels of organic matter and phosphorus. The major challenge of this
project is to reverse this trend and to ensure food security, improve nutrition, and create
opportunities for generating additional income while maintaining the natural resource base
and protecting the environment. Working in a team, the project scientists are developing a
deeper understanding of soil, nutrients and weed processes, developing improved component
technologies involving cereals, legumes, and livestock, packaging them into best-bet options
and testing and validating them in relevant agroecologies.
A great deal of progress was made during the year although all the results are not in yet.
Several experiments on weed, Striga, and balanced nutrient management strategies were
conducted. Improved high yielding N-efficient maize varieties, and P-efficient cowpea and
soybean varieties with high biological N-fixation were developed with grain yields over
20% higher and fodder yields over 15% higher than the local varieties. Beneficial effects of
cereal–legume rotation and relay cropping were established and quantified. Best-bet options
involving “cereal–legumes” and “cereal-legumes–livestock” and “cotton–cowpea” combining
integrated pest management were developed and tested on farmers fields with significant
superiority and higher benefit : cost ratio over farmers’ practices. The success of these best-bet
options has attracted several donors including USAID, DFID, DANIDA, GATSBY, IFAD,
CIDA Belgium, Japan, etc., who are funding about 15 special projects to test, validate, and
disseminate these options. In the 2003 crop season, over 900 farmers participated in on-farm
evaluation of best-bets involving sorghum–cowpea in the Sudan savanna and “maize–double
cowpea” in the northern Guinea savanna and obtained 100 to 300% increase in productivity.
The farmer-to-farmer diffusion of an improved cowpea variety covered over 27 000 farmers
in Kano State of Nigeria and this appeared to be a very powerful model for technology dis-
semination. A systematic transect survey revealed high rates of adoption of IITA’s improved
maize, cowpea, and soybean varieties in northern Nigeria. NARES capacity to generate and
transfer technologies including postharvest technologies was enhanced through degree and
non-degree related training, technical backstopping, monitoring tours, workshops, field
days, extension materials, and networks such as WASNET, PRONAF, and WECAMAN.
A centrally commissioned external review (CCER) of this project was conducted and the
project scientists were congratulated for the good progress made and team work in develop-
ing a well integrated and functioning project.
Promoting Integrated Control of Imperata and Other Weeds
in The Savannas of Nigeria
D. Chikoye, O. Nielsen, P. Kormawa, G. Tarawali, and partners from national
Weeds are one of the major constraints preventing higher crop productivity in Africa. Weeds
reduce crop yields and farm size, and increase drudgery and the cost of crop production. Hand
hoeing is the predominant method of weed management in most small-scale farms. Adop-
tion of improved weed management technologies is low because of poor linkages between
researchers, extension agencies, and farmers. Participatory research and extension approaches
(PREA) were implemented in the savanna to help improve the effectiveness of improved
Imperata management technologies and increase the likelihood of adoption by small-scale
farmers. The technology development process consisted of community mobilization, prob-
lem diagnosis, action planning, experimentation, monitoring, and evaluation. Dissemina-
tion of results was through the mother–baby approach and field days. The “mother trials”
were researcher-designed and managed demonstration on-farm trials consisting of a wide
range of weed control options. These afforded farmers and extension staff an opportunity
to observe and compare different Imperata management options. Farmers selected one or
two technologies from the mother trials, which they tested under their farming conditions.
The farmer-managed subsets of technologies under evaluation in mother trials are called
“daughter trials”. IITA researchers teamed with partners with comparative advantage in
technology transfer (Federal, State, local governments, and community-based institutions)
to create effective linkages between research results and farmers.
Managing Striga on Cowpea and Maize Cropping Systems
A.M. Emechebe, B.B. Singh, A. Menkir, G. Tarawali, and B. James
The parasitic angiosperm, Striga is an obligate root parasite, which infects cereal and legume
crops in sub-Saharan Africa (SSA). S. hermonthica, endemic and most widespread in Africa,
constitutes the most important biological constraint to cereal production in SSA while S.
gesnerioides, together with a related parasitic flowering plant (Alectra vogelii), is second only to
all insect pests as the most important constraint to cowpea production. Between 21 and 50
million ha of agricultural land in SSA is severely infested by Striga spp. causing annual crop
losses valued variously at between US$500 and US$3 billion. For the control of S. gesneri-
oides, IITA, in collaboration with other research institutes, has developed several technology
options such as: (i) growing resistant varieties, (ii) planting cowpea seeds not contaminated by
S. gesnerioides seeds, (iii) hoe-weeding and hand-pulling emerged Striga plants before seed
maturity, and (iv) seed treatment with imazaquin. Similarly, (i) use of resistant/tolerant
cultivars, (ii) planting Striga-free seeds, (iii) hoe weeding, earthing-up and hand-pulling,
(iv) rotation with trap crop cultivars selected for enhanced capacity to induce suicidal ger-
mination of S. hermonthica seeds, (v) seed treatment with ALS-inhibiting herbicides, and
(vi) application of high doses of N fertilizers have been considered as options for control-
ling S. hermonthica. However, these options need to be used in an integrated manner to
control Striga under farmers’ conditions. Although farmers have a good perception of the
magnitude of the Striga problem, they lack the necessary knowledge of certain aspects of
its epidemiology that make its control difficult. To overcome this constraint, IITA has used
special project funds to train farmers and village-level extension agents to empower them to
participate effectively in technology identification, development, testing, adaptation, and
adoption, thereby enhancing farmer ownership and up-take of Striga management options.
Several other technologies that are receiving research attention on-station at IITA are also
Matching Crops and Soils Using INRM in The Dry and Moist
J. Diels, A.Y. Kamara, R. Abaidoo, L. Franke, D. Chikoye, G. Dercon, and
N. de Haan
Savanna soils are inherently low in nitrogen, plant-available P, and are known to develop
deficiencies of K, Ca, Mg, Zn, and/or S depending on precipitation, parent material, and
the level of intensification and nutrient management. Drought stress during the cropping
season often acerbates such constraints, in particular towards both the drier and the wetter
limit of the savanna (transition zone from bimodal to monomodal rainfall). The simultane-
ous occurrence of several soil constraints, often in combination with poor weed and pest
management, and an imbalanced supply of soil nutrients by the farmers, leads to low nutri-
ent use efficiencies.
Several complementary strategies can be followed to improve resource use efficiency. First
we can match crops to the soil conditions by improving the resource use efficiency through
breeding. A second strategy consists of balancing the supply of the different nutrients,
which improves resource capture and utilization at the same time. Similarly, we can increase
the water use efficiency by improving nutrient supply to the crops, or vice-versa improve
nutrient use efficiency through better water availability. Better weed and pest control is
another important strategy.
The development of varieties with a higher resource use efficiency can be achieved
either by selecting for better resource capture (uptake of water and nutrients) and/or better
resource utilization (more grain produced per unit of water or nutrient taken up). The
present improvements in N-use efficiency of maize by the IITA maize improvement program
are largely due to a higher efficiency of N uptake due to the development of varieties that
have a more efficient root system, but also due to gains in N utilization efficiency. It was
moreover found that N uptake efficiency in maize is correlated with root-pulling resistance
and resistance to drought. Selection for better N uptake truly reduces N losses, whereas
selection for increased N utilization may lead to lower protein content in the grains and/or
the fodder, or a higher grain to fodder ratio. So there is a need to weigh carefully the gains
in terms of N utilization efficiency against possible disadvantages for consumers and
It is sometimes argued that varieties with higher uptake efficiency will further deplete the
soils. In case of nitrogen, that is not true. Mineral nitrogen is highly mobile, and most of the
nitrogen that is not be taken up by the crop will leach downward out of reach for the next
year’s crops. Phosphorus is not mobile, and a more efficient P uptake, either from soluble P
or from sparingly available P forms in the soils, will help to improve yields on the short term,
but also accelerate soil P depletion. However, a variety that shows an increased yield response
to soluble P fertilizer, and/or phosphate rock allows the farmers to have an earlier return on
their investment in P fertilizer or phosphate rock, and it may convince them of the need
to use adequate amounts of P fertilizer or phosphate rock. Current screening of legumes at
IITA indicates clear differences in P use efficiency in cowpea and soybean germplasm. But
there is a need to develop a reliable and sensitive field or greenhouse screening method to
identify P efficient genotypes.
It is well known that productivity gains achieved by introducing an improved variety
are greater under better soil and crop management. Also, the benefit of better soil/crop
management is more expressed with improved varieties. And according to Liebscher’s law, the
use efficiency of one resource (radiation, water, or a plant nutrient) is increased when other
limitations, including pests and weeds, are reduced. The implication of these interactions
is that constraints are best tackled simultaneously, and the benefits of technology compo-
nents are best realized by combining them in systems. That is the very essence of integrated
natural resource management (INRM), the idea of optimizing the use of all resources in an
It is often argued that farmers adopt only components, not complex systems. Yet, ongo-
ing work in the savanna project indicates that farmers can adopt complex systems when a
basket of components or options is offered to them, and such options are codeveloped and
assembled into systems in close interaction with them. Investment in the training of extension
agents, farmers, and other stakeholders is one of the keys to success. The major challenge
is to find the most cost-efficient way of disseminating complex technologies on a grander
scale. Different approaches are currently used in the savanna project. Properly documenting
and evaluating these efforts will provide most valuable insights.
Functions of The Contracts and Grants Office at IITA
In June 2003 a new “Contracts and Grants Office” (C&GO) was established at IITA. Cur-
rently it has three staff members: Alexander Schöning (Ibadan), Sharmini Blok (Singapore),
and Anthony Williams (Ibadan). The role of C&GO is to serve as the central link between
development investors, on the one hand, and IITA’s scientists and financial unit on the other.
All official correspondence to investors is now expected to go through C&GO in order to
have one single point of contact and to facilitate follow-up with both investors and IITA.
To make proposal writing at IITA more efficient and increase the probability of success,
C&GO will be responsible for the following key tasks:
1. Submission/follow-up of proposals and reports
2. Development and coordination of complex proposals (“mega-proposals”)
needing input from various sources
3. Review of all other proposals prior to submission
C&GO also handles contractual matters of the institute and helps in identifying new
funding opportunities in collaboration with IITA management and Communication and
Information Services (CIS).
For the purpose of maintaining records on all donor-related issues, different databases are
being developed by C&GO. The main database will contain information on development
investors and IITA projects. All official documents regarding donors, projects, funding and
reporting cycles will be electronically managed, while an automated system will take care of
timely reporting. It is planned to make this database available on the IITA-intranet during
2004. A second database is being developed to provide quickly the standard information
frequently required for proposals. It will contain information on IITA’s capabilities with
regard to different commodities and regions in sub-Saharan Africa. This database will also
include short resumés of IITA scientists. In addition, a roster of consultants will be built up
over the coming months. To ensure that the design and management of these databases will
be user-friendly and in keeping with the needs of the institute, C&GO counts on inputs
and feedback from IITA scientists.
In cooperation with Budget & Finance (B&F), C&GO reviews budget proposals for
new projects, keeps track of technical reporting, and monitors core budget centers on a
monthly basis. Further tasks of C&GO are the supervision of the Training Unit (capacity
building) which is now part of this office, and provision of administrative support to the
Research for Development Council (R4DC). C&GO reports to IITA’s Director of Research