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Working with farmers to control sweet potato virus disease in East Africa

This is a brief summary of the purpose of the ‘‘Working with farmers to control sweet potato virus disease in East Africa’’ project, research activities, outputs of the project, and the contribution of the project towards DFID’s development goals. This project used participatory varietal selection trials as a tool to test a range of varieties with farmer groups in Uganda and Tanzania. Resistance to sweet potato virus disease (SPVD) previously identified in varieties bred in Uganda remained effective in all locations. Farmers were very keen to obtain the range of varieties tested and, rather than selecting a few, wished to retain all varieties to test over a longer period in their own gardens. For long-term retention, drought resistance seems to be a key factor. Several of the Ugandan varieties performed very well in Kagera Region, Tanzania, and an important achievement of the project seems to be the improved links between Ugandan and Tanzanian scientists based in Namulonge and Maruku research institutes respectively. Despite the effectiveness of resistance to SPVD, several highyielding and popular landraces and orange-fleshed, high vitamin A varieties are only moderately SPVD-resistant. For these, the project has identified roguing as an additional and effective control practice that is easy for farmers to adopt. Isolation of new crops was, by contrast, difficult for farmers to use. Posters, brochures, training notes and protocols for training have been developed by both the Ugandan and Tanzanian teams, sharing materials where possible. Material is available in local languages. These training materials have also been reproduced and disseminated. Unlike in Uganda, resistant varieties were not widely available in Tanzania and the project has collaborated with other organisations to ensure their rapid multiplication and dissemination. Collaboration with other organisations has also been key to extensive training of both farmers and extensionists there. Participatory on-farm breeding has also been done in both Uganda and Tanzania. Biotic [SPVD and Alternaria] and abiotic [drought and infertile soil] factors interacted with farmers’ [mainly concerned with storage root characteristics] and breeders’ [mainly concerned with storage root characteristics and disease resistance] selection criteria in determining which plants were retained. A few clones have been identified which appear to be higher yielding than the farmers available landraces yet resistant to SPVD and Alternaria: farmers are keen to continue the participatory breeding process.


Gibson, R.W. 2006. Working with farmers to control sweetpotato virus disease in East Africa. Natural Resources Institute, Chatham Maritime, Kent. ME4 4TB, UK.