2009-2011
Root and Tuber System
Centers/ProgramsIITA
Target RegionsSSA
Countries of Planned Research Potential Beneficiary Countries
 
Angola, Burundi, Benin, Central African Republic, Switzerland, Côte d'Ivoire, Cameroon, Congo, Dem. Rep., Ethiopia, Ghana, Kenya, Liberia, Madagascar, Mozambique, Malawi, Nigeria, Rwanda, Sierra Leone, Swaziland, Togo, Tanzania, Uganda, South Africa, Zambia, Zimbabwe
 
Angola, Burundi, Benin, Burkina Faso, Botswana, Central African Republic, Côte d'Ivoire, Cameroon, Congo, Dem. Rep., Congo, Rep., Comoros, Djibouti, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Gambia, Guinea-Bissau, Equatorial Guinea, Kenya, Liberia, Lesotho, Madagascar, Mali, Mozambique, Mauritania, Mauritius, Malawi, Namibia, Niger, Nigeria, Rwanda, Sudan, Senegal, Sierra Leone, Somalia, Sao Tome and Principe, Swaziland, Seychelles, Chad, Togo, Tanzania, Uganda, South Africa, Zambia, Zimbabwe
CGIAR Priorities
2A - Maintaining and enhancing yield potential of food staples
2B - Tolerance to selected abiotic stresses
3B - Income increases from livestock
4A - Integrated land, water and forest management and landscape level
4D - Sustainable agro-ecological intensification in low- and high-potential environments
5A - Science and technology policies and institutions
5B - Making international and domestic markets work for the poor
5C - Rural institutions and their governance
5D - Improving research and development options to reduce rural poverty and vulnerability
Development Activities - Development Activities
Financing Sources
Members: European Commission, FAO, France, Germany, IFAD, Japan, Kellogg Foundation, Netherlands, Nigeria, Rockefeller Foundation, Sweden, Switzerland, United States, World Bank

Non Members: AGIP, ASARECA, Bill and Melinda Gates Foundation, Catholic Relief Services, Common Fund for Commodities - CFC, CTA, Gatsby Foundation, Global Crop Diversity Trust (GCDT), Mozambique, National Space Dev. Japan, Ohio University, Plan International, Private Sector, Sasakawa Africa Association, SPDC/ Cassava Enterprise Dev't, University of Florida - UFL, University of Hohenheim, University of Nottingham, Unres+Other Sources, VirginiaTech
Project Overview and Rationale


Tropical root and tuber crops (cassava, yam and cocoyam) are major staples in large parts of humid and subhumid sub-Saharan Africa (SSA). For example, SSA produces over 50% of the cassava (Manihot esculenta Crantz) and over 90% of the yam (Dioscorea spp.) in the world. These crops are largely produced by smallholders who rely on traditional, labor-intensive, practices that do not allow for optimal exploitation of the crops’ productive potential. Although constraints differ with agroecology and specific crops, all the crops suffer severe yield losses due to a wide range of pests and diseases (fungal and bacterial root and tuber rots, viruses, insects, mites, nematodes and rodents), low nutrient availability, inappropriate germplasm and postharvest technologies. Production and postharvest practices still lack appropriate levels of mechanization to reduce the labor for land preparation, planting, weeding, harvesting, processing and storage. Innovations geared towards increased productivity in root and tuber systems are necessary.

Cassava provides affordable food for rapidly growing urban populations in addition to which new market opportunities in the starch and livestock feed industries are opening up. However, production costs are comparatively high in SSA. Yam is a traditional African crop of increasing importance. Due to consumer preference for yam over other roots and tubers there will be greater demand for it with increasing incomes in West and Central African (WCA) countries. However, the high labor and high soil fertility requirement of yam are threatening its future. Cocoyam and taro are important traditional crops, playing a vital role for women in family food supply and income generation. Similar to yam, these crops are preferred staples but they have not received sufficient research attention.

Expanding the scale of production, mainly of cassava, spurred by increasing demand and conducive policies, requires postharvest technologies capable of processing larger quantities into quality products. The entire sector then experiences a shift from small-scale household processing to large-scale agroenterprises. This requires good knowledge of the commodity chain and the technical equipment to move processing up to an industrial scale. New food and nonfood products are being developed to expand the market and create future income-generating opportunities. Significant germplasm improvements for greater yield and disease resistance have been made, and major breakthrough biological control measures have secured future production, especially of cassava. Root and tuber crops export substantial proportions of soil nutrients with the harvested products. Greater yield will thus lead to soil nutrient depletion if not accompanied by appropriate and sustainable soil nutrient management strategies. Poor crop husbandry in “no or low input” smallholder systems aggravates yield losses due to late or insufficient weeding, low planting densities, inappropriate intercrops, untimely planting and harvesting and poor processing techniques. The low yields, high production costs, and thus, low productivity of many root and tuber systems are in stark contrast with the economic opportunities.

A framework to guide the activities of the Root and Tuber Systems Program has been developed from meetings of members and selected partners of the Program in November 2006 and October and November 2007. The identification and prioritization of strategic and tactical objectives was based on such factors as past achievements, analysis of the opportunities and challenges in the target environment, and suggestions in the report of the recent EPMR. For instance, the EPMR panel rightly pointed out that “breeding programs for both crops (cassava and yam) appear ready to meet short-term challenges from pests and diseases. …However the programs appear less well prepared to meet the challenges of intensification that will surely occur in the next decade.” The report went on to state, “The Panel strongly suggests that breeding procedures be modified to ensure that fertilizer responsiveness is determined at the progeny level during selection by routine evaluation under at least two diverse fertility regimes, following an assessment of historic data for the presence of genotype × fertility level interactions.” In terms of program structure the Panel commented, ”While the new Project structure should work well for varietal improvement, it is less clear if this grouping will result in integrated sustainable farming systems in which both crops play important parts. This research is allocated to Output 4: integration of improved component technologies, where it attracts one activity. To the Panel, this appears to be an inadequate attempt to exploit the characteristics of improved germplasm through better crop management, and it strongly encourages further agronomic research on these two crops.”

The goal of the Root and Tuber Systems Program is that the contributions of the root and tuber crop subsector to AgGDP and GPD in SSA will double in the major root crop producing countries by 2018 compared with 2009 levels. In pursuance of this goal there are five objectives:
  • Increased productivity of root and tuber crops,
  • Value added to produce and expanded markets,
  • Reduced producer and consumer risks,
  • Advocacy and proposal of policy reforms,
  • Documentation of program impact.

    This prioritized set of objectives places better focus on two key challenges: raising and sustaining crop productivity in the face of a declining resource base, and expanding the market opportunities for value-added products. Addressing these challenges is crucial to the future role of tropical root and tuber crops in the economies of SSA. The development of the program framework has necessitated a revision of the outputs in this MTP.

    Project Outputs
    Output Title
    1: Productive and sustainable soil and crop management systems designed
    Output Description
    Cultivation of cassava and yams in SSA occurs at a low level of productivity that limits the profit margin and makes products uncompetitive. Productivity of yam cultivation is being limited by decreasing soil fertility associated with intensification of cultivation and the high costs of planting material and labor. Rapidly increasing areas and intensification of cassava production, for instance in parts of Nigeria, are clearly showing the need for urgent and serious attention on soil management issues if production and productivity are to be sustained. Activities under this output are targeted at significantly raising the productivity levels, through strategies and practices that are sustainable. Studies will be conducted on nutrient requirements, influences on nutrient uptake and use efficiency and the role of mycorrhiza in mineral nutrition. The role of cover crops in maintaining soil fertility, soil organic matter and the management of nematodes is being investigated, especially in yam systems in West Africa. There are complementary studies on the use of chemical and organic fertilizers. As these are vegetatively propagated crops, the planting material systems and the propagation ratios for the tropical root crops, especially yam, require improvement. Work will be conducted that will build on past progress to develop a robust and profitable system that will be adopted by the private sector.
    CGIAR Priorities
    2A, 2B, 4D
    Countries of Planned Research
    Benin, Switzerland, Côte d'Ivoire, Cameroon, Congo, Dem. Rep., Ghana, Kenya, Liberia, Madagascar, Mozambique, Malawi, Nigeria, Sierra Leone, Togo, Tanzania, Uganda, South Africa, Zambia, Zimbabwe
    Intended Users
    NARES, CGIAR, and ARI scientists; private sector
    Outcome
    Increased productivity and sustainability of root and tuber crop systems; reduced environmental degradation
    Impact
    Increased wealth from yam and cassava cultivation and improved natural resources"

    Output Target
    Year Target Type Target Description
    2009
    Other kinds of knowledge
    Effect of mycorrhiza on nutrient uptake and use efficiency by D. rotundata and D. alata
    2009
    Other kinds of knowledge
    Established relationship between nitrogen level and the accumulation and repartitioning of biomass in yam (Dioscorea rotundata)
    2009
    Other kinds of knowledge
    Factors influencing yield levels and fertilizer response of cassava varieties in the midaltitude zone
    2009
    Other kinds of knowledge
    Soil factors influencing the diversity of VAMF species that colonize roots of cassava genotypes
    2009
    Practices
    A leguminous cover crop system for weed control and soil fertility management in yam cultivation
    2010
    Other kinds of knowledge
    Diversity among cassava genotypes for colonization by mycorrhizal fungi (VAMF) and dependency on VAMF for P, K and N nutrition determined
    2010
    Other kinds of knowledge
    Mechanism for drought tolerance in cassava
    2010
    Other kinds of knowledge
    Variation in spore population structure of arbuscular mycorrhiza fungi in yam production systems
    2011
    Other kinds of knowledge
    Variation in competitive ability under intercropping of local and improved cassava varieties in the midaltitude zone

    Output Title
    2: Strategies to mitigate biological risks developed
    Output Description
    The significant progress made in addressing the challenges of pests and diseases of root crops has had major positive impact in SSA and beyond. However, the frequent occurrence of new pests and new strains of old pests especially of cassava necessitates vigilance and continued studies to ensure adequate protection of crops in the field and of produce in storage. The shortening of fallow periods in traditional yam-based systems is associated with increasing pressure from a range of insect pests (e.g., leaf and tuber beetles, mealybugs, scales), fungal (e.g., anthracnose, leaf spot, leaf blight, tuber rots) and viral diseases, as well as nematodes that contribute to suboptimal yields and the deterioration of tuber quality in storage. Studies will be conducted to generate knowledge on biological risks to root and tuber production and postharvest systems, and design of strategies to mitigate them. Emphasis for cassava is on brown streak disease, damage from apparent variants of the cassava mosaic virus, and whiteflies, especially in East and Southern Africa. In Central Africa there will be additional focus on managing the root and tuber scale including the search for and deployment of host plant resistance. In terms of yam diseases the focus remains on viruses (especially yam mosaic virus) and anthracnose. Research will also continue to address the pre- and postharvest damage from nematodes and the increasing threat of tuber mealybugs.
    CGIAR Priorities
    4D, 5B, 5C
    Countries of Planned Research
    Angola, Burundi, Benin, Central African Republic, Côte d'Ivoire, Cameroon, Congo, Dem. Rep., Ghana, Kenya, Mozambique, Malawi, Nigeria, Rwanda, Sierra Leone, Togo, Tanzania, Uganda, South Africa
    Intended Users
    NARES, CGIAR, and ARI scientists; private sector
    Outcome
    Reduced losses and increased stability in cassava and yam production and postharvest systems
    Impact
    Increased food security, and assurance of wealth and health"

    Output Target
    Year Target Type Target Description
    2009
    Other kinds of knowledge
    Distribution of at least one fungal or bacterial disease of cassava in the humid forest ecoregion
    2009
    Other kinds of knowledge
    Economics of impact of cassava brown streak disease in eastern Tanzania and Zanzibar
    2009
    Other kinds of knowledge
    Geographic and host-type diversity of African root and tuber scale (ARTS)
    2009
    Other kinds of knowledge
    Impact (ex-ante) of biotechnology research for control of cassava brown streak disease in eastern and southern Africa
    2009
    Other kinds of knowledge
    Parasitoids of Bemisia whiteflies established in at least one country in East Africa
    2009
    Other kinds of knowledge
    Reduction in yam storage rot through biological control
    2009
    Practices
    Cultivar mixtures for management of yam anthracnose disease
    2010
    Other kinds of knowledge
    Environmental factors affecting the proliferation of Anoplolepis tenella in Central Africa
    2010
    Other kinds of knowledge
    Identity and distribution of mealybug complex infesting field and stored yam
    2010
    Other kinds of knowledge
    Persistence and impact of parasitoids on spiraling whitefly abundance determined in at least one country in East Africa.
    2011
    Other kinds of knowledge
    Factors underlying persistent mealybug infestations in field and stored yams
    2011
    Other kinds of knowledge
    Impact of at least one virulent pathogen of ARTS and its associated ants in field
    2011
    Practices
    Effectiveness of fallow management for control of the African root and tuber scale in two countries in the Congo Basin

    Output Title
    3: Pest-resistant, and water- and nutrient use-efficient germplasm
    Output Description
    The emerging challenges in terms of climate change, increasing pest pressures, cultivation of root and tuber crops on marginal land, and rapidly declining soil fertility call for specific response in terms of better suited varieties. Work in outputs 1 and 2 will contribute component technologies for addressing these challenges. The development and delivery to partners of varieties that are pest resistant and efficient in the use of water and nutrients are essential components that will enable an integrated and sustainable approach towards increased productivity and production. Conventional approaches have been successful in the past but the availability of molecular tools provides opportunities to raise the efficiency of finding and using sources of the relevant traits. We have established partnerships with ARIs (e.g., Danforth Center, USA; Copenhagen University, Denmark; Ohio State University, USA) to facilitate this. Our partnership with CIAT, Colombia also guarantees access to a broad range of germplasm as sources of desired traits.
    CGIAR Priorities
    2A, 2B, 4D
    Countries of Planned Research
    Angola, Benin, Côte d'Ivoire, Cameroon, Congo, Dem. Rep., Ethiopia, Ghana, Liberia, Mozambique, Malawi, Nigeria, Sierra Leone, Swaziland, Togo, Tanzania, Uganda, South Africa, Zambia, Zimbabwe
    Intended Users
    NARES, CGIAR, and ARI scientists 
    Outcome
    More productive and resilient cassava and yam varieties released by NARS; Increased production of roots and tuber; better use of natural resources
    Impact
    Increases in income and food security from cassava and yams are more stable and wide spread in SSA"

    Output Target
    Year Target Type Target Description
    2009
    Materials
    Cassava germplasm with multiple genes for CMD resistance
    2009
    Materials
    Transgenic cassava of African origin resistant to CMD and/or CBSD
    2009
    Practices
    Robust tools for cassava abiotic stress screening in the field and glasshouse
    2010
    Materials
    Inter-generic hybrids of cassava × castor
    2010
    Materials
    Molecular markers linked to cassava root rot resistance
    2010
    Other kinds of knowledge
    Fifty SNP markers on a genetic linkage map of cassava
    2010
    Other kinds of knowledge
    New sources of drought tolerance in cassava
    2011
    Materials
    Molecular-assisted breeding used for tolerance to CBSD
    2011
    Materials
    Sources germplasm with resistance to the African root and tuber scale

    Output Title
    4: Safe and competitive value-added products
    Output Description
    Demand for yam is subject to volatility because of the limited number of its processed forms, poor market linkages and inconsistent policies affecting prices of other cheap energy sources. Expanded opportunities for using the produce through processing into various products and improvements in marketing channels will also boost efforts at increased productivity and bring the benefits from the crop to a broader range of consumers. Both the storage roots and leaves of cassava are used as food. About 70% of the storage root production is processed into a variety of pastes, flours, etc., serving both rural and urban populations as a basic daily source of dietary energy. Roots are also consumed freshly boiled or raw as a snack. The leaves are eaten as a vegetable, providing a cheap and rich source of protein, minerals, and vitamins. The market opportunities for root and tuber products would be expanded through value addition to the produce but also through analysis of global commercial cassava systems. The research and development of safe and competitive products of cassava and yams with partners, determination of safety thresholds in food and feed products, and the design of guidelines for compliance with trade and quarantine obligations will be a research focus and will be crucial to ensure international competitiveness, access to and stability of, the markets. Breeding objectives would also take into account the preferred end use characteristics which will be known as a result of the research with processors and others in the private sector.
    CGIAR Priorities
    2A, 5A, 5B, 5C
    Countries of Planned Research
    Burundi, Benin, Cameroon, Congo, Dem. Rep., Ghana, Kenya, Liberia, Madagascar, Mozambique, Malawi, Nigeria, Sierra Leone, Swaziland, Togo, Tanzania, Uganda, South Africa
    Intended Users
    NARES, CGIAR, ARI, private sector 
    Outcome
    Broader and more reliable range of markets for cassava and yam products; increased income from root and tuber production and processing
    Impact
    Increased contribution of cassava and yams to AgGDP in SSA "

    Output Target
    Year Target Type Target Description
    2009
    Other kinds of knowledge
    Bioavailability of provitamin A (Caco- 2 cell model) in at least 2 yellow- fleshed cassava and 8 yellow-fleshed yam varieties
    2009
    Other kinds of knowledge
    Cost benefit analysis of integrated cassava production and processing systems in Tanzania and Zanzibar
    2010
    Other kinds of knowledge
    Consumer acceptability of gari produced from yellow-fleshed cassava roots
    2010
    Other kinds of knowledge
    Extent of contamination by toxigenic Aspergillus species and aflatoxins in cassava chips
    2010
    Other kinds of knowledge
    Functional, physical and chemical characteristics of yam required by different industries
    2010
    Unassigned
    Competitiveness of cassava or yam under different fertilizer policy regimes and land intensification pathways documented in at least one major producing country
    2011
    Capacity
    Functional market chain linkages for cassava chips in East and Central Africa
    2011
    Other kinds of knowledge
    Microorganisms associated with food losses in edible roots and leaves of CBSD-infected cassava plants
    2011
    Other kinds of knowledge
    The effect of climate change on cyanide potential and other quality characteristics of cassava
    2011
    Practices
    Cassava starch modification to suit different industrial needs

    Output Title
    5: Policy reforms proposed and advocated 
    Output Description
    There are policy constraints to the development of the root and tuber crops subsector in several countries in Africa, including the major producing countries. Studies would be conducted on such constraints and any opportunities and results would form the basis for advocacy at high levels of government. Analysis of the influence of constraints, such as the lack of protocols for release of new varieties and seed regulations of root and tuber crops by national programs, should offer sufficient data to address the current restrictions. The competitiveness of root and tuber crops under different fertilizer policy regimes and land intensification pathways will also be modeled to provide information to policymakers.
    CGIAR Priorities
    5A, 5B, 5C
    Countries of Planned Research
    Benin, Cameroon, Congo, Dem. Rep., Ghana, Kenya, Madagascar, Mozambique, Malawi, Nigeria, Sierra Leone, Togo, Tanzania, Uganda, Zambia
    Intended Users
    National Policymakers, NARES, CGIAR, private sector, regional research and trade organizations, NEPAD, FARA, AU
    Outcome
    More effective policies in the root and tuber crop sector; Increased profitability for farmers, processors, and traders; Better managed natural resources; more efficient and effective research
    Impact
    Better science based development"

    Output Target
    Year Target Type Target Description
    2009
    Other kinds of knowledge
    Inventory of policies and other economic factors that influence development of root and tuber sector
    2010
    Other kinds of knowledge
    Competitiveness of cassava or yam under different fertilizer policy regimes and land intensification pathways in at least one major producing country
    2011
    Other kinds of knowledge
    Harmonized variety release protocols and seed regulations for vegetatively propagated crops in Southern Africa

    Allocation of Member, Non-Member Grants and other sources to projects, 2007-2009
    in $millions

    Project Member Actual
    2007
    Estimated
    2008
    Proposal
    2009
    Project Total
    14.176
    14.058
    13.295
    Root and Tuber SystemsMemberEuropean Commission
    1.990
    0.798
    0.848
    FAO
    0.093
    0.397
    0.431
    France
    0.087
    0.088
    0.088
    Germany
    0.006
    0.051
    0.037
    IFAD
    0.647
    0.641
    0.605
    Japan
    0.204
    0.218
    0.215
    Kellogg Foundation
    0.136
    0.298
    0.298
    Netherlands
    0.293
    0.320
    0.320
    Nigeria
    0.052
    1.120
    0.000
    Rockefeller Foundation
    0.420
    0.292
    0.181
    Sweden
    0.018
    0.000
    0.000
    Switzerland
    0.035
    0.052
    0.043
    United States
    4.702
    5.061
    3.921
    World Bank
    0.000
    0.100
    0.000
    Non MemberAGIP
    0.007
    0.036
    0.036
    ASARECA
    0.000
    0.052
    0.052
    Bill and Melinda Gates Foundation
    0.000
    0.000
    1.513
    Catholic Relief Services
    0.316
    0.000
    0.000
    Common Fund for Commodities - CFC
    0.126
    0.449
    0.547
    CTA
    0.000
    0.001
    0.000
    Gatsby Foundation
    0.008
    0.010
    0.000
    Global Crop Diversity Trust (GCDT)
    0.000
    0.300
    0.300
    Mozambique
    0.012
    0.000
    0.126
    National Space Dev. Japan
    0.015
    0.038
    0.038
    Ohio University
    0.002
    0.002
    0.002
    Plan International
    0.000
    0.092
    0.092
    Private Sector
    0.615
    0.153
    0.098
    Sasakawa Africa Association
    0.055
    0.000
    0.000
    SPDC/ Cassava Enterprise Dev't
    1.161
    0.250
    0.250
    University of Florida - UFL
    0.006
    0.011
    0.000
    University of Hohenheim
    0.006
    0.003
    0.003
    University of Nottingham
    0.000
    0.015
    0.000
    VirginiaTech
    0.005
    0.001
    0.001
    Unres+Other SourcesUnres+Other Sources
    3.159
    3.209
    3.250


    Allocation of Project Costs to CGIAR Priorities, 2007-2011
    in $millions

    Project Actual
    2007
    Estimated
    2008
    Proposal
    2009
    Plan 1
    2010
    Plan 2
    2011
    Priorities
    Root and Tuber Systems
    Project Total
    14.176
    14.058
    13.295
    13.345
    13.391
    2A
    6.153
    7.545
    6.913
    6.672
    6.695
    2B
    0.740
    0.572
    0.665
    0.934
    0.937
    3B
    0.057
    0.000
    0.000
    0.000
    0.000
    4A
    0.047
    0.000
    0.000
    0.000
    0.000
    4D
    5.587
    4.599
    4.348
    4.364
    4.379
    5A
    0.948
    0.821
    0.771
    0.774
    0.777
    5B
    0.123
    0.385
    0.359
    0.360
    0.362
    5C
    0.326
    0.136
    0.133
    0.133
    0.134
    5D
    0.195
    0.000
    0.000
    0.000
    0.000
    Development Activities
    0.000
    0.000
    0.106
    0.108
    0.107


    Project investment by developing Region, 2007-2011
    in $millions

    Project Target Regions Actual
    2007
    Estimated
    2008
    Proposal
    2009
    Plan 1
    2010
    Plan 2
    2011
    Project Total
    14.176
    14.058
    13.295
    13.345
    13.391
    Root and Tuber SystemsSSA
    14.176
    14.058
    13.295
    13.345
    13.391