Regional germplasm development and deployment for sustainable production and utilization within the cassava sub-sector

  J.B.A Whyte, B.W. Khizzah, A. Dixon, N.M. Mahungu, P. Ragama, P. Ntawuruhunga & H. Ojulong

Lack of food security for a large segment of the sub-region’s population continues to exacerbate poverty and malnutrition. The high population growth, HIV effects on the productive labour force, degradation of environment, poor agricultural development support services and lack of enabling economic policy environment has aggravated the situation. Cassava has great potential and can play a critical role in contributing to food and nutritional security, income generation, poverty alleviation and socio-economic growth of the sub-region. The major diseases and pests that plague cassava production in these ecologies include; cassava mosaic diseases, bacterial blight, Anthracnose, mealy bug, green mite, nematodes and termites. Yield losses of 80 to 100% could be attributed to a combination of these biotic stresses. Fungal infection and a wide range of insects and other microorganisms during processing and handling may lead to the formation of mycotoxins making chips unable to meet trade and health standards. The larger grain borer (Prostephanus truncatus (Horn)) is currently the most serious pest of dried cassava in storage causing weight losses as high as 70% after four months of storage. Lack of clear-cut policies for the development of the sub-sector has also contributed to low production of cassava in the region.  In collaboration with its partners a germplasm development and deployment strategy for sustainable production and utilization within the cassava sub-sector was established in Uganda, Kenya and Rwanda to generate improved populations with desired characteristics targeting different end uses/markets, avail the populations to partners for evaluation and selection under specific agro-ecosystems and establish special backup populations. The scheme comprising of sib-family seedling nursery, clonal characterisation and performance evaluation, has ensured that the improved populations have the necessary resistance/tolerance background to the major biotic stresses, and good agronomic and root quality characteristics. Use of open quarantine facilities has enabled the introduction of improved clones into Kenya, Tanzania, Rwanda, Burundi, D R Congo, Southern Sudan and Mozambique with significant reduction in the cost of exchanging cassava using tissue cultured material. It has also shortened the time required for release of a variety by approximately three years. The clones have formed the basis of multi location and farmer participatory evaluation and multiplication in these countries. This process has enriched the cassava genetic base of the national germplasm collection and under the current epidemic situation has provided a highly efficient regional solution for the cassava farming community. The farmer participatory approach to cassava evaluation has permitted rapid assessment of large numbers of improved clones, facilitated greater researcher-farmer collaboration, and enabled the network to target stable genotypes across the region.