Sweetpotato (Ipomoea batatas; Convolvulaceae) is an important subsistence, food security and famine relief crop in sub-Saharan Africa where its cultivation area grows faster than any other subsistence crop. It is a “women’s crop” cultivated by women for the family’s daily needs. It performs well in relatively poor soils, has high tolerance to drought and a good nutritional value (especially the yellow-flesh varieties). With an annual production of 126 million tons, sweetpotato ranks as the fifth most important food crop in the developing countries after rice, wheat, maize, and cassava. The highest production per capita is in East Africa, in the countries around Lake Victoria, and the biggest producer is Uganda. Viruses cause the main disease of sweetpotatoes. The ‘sweetpotato virus disease’ (SPVD) can result in a complete yield loss. It develops in co-infection of SPCSV (crinivirus) with SPFMV (potyvirus) or SPMMV (ipomovirus) (positive-sense ssRNA viruses). SPFMV and SPCSV are the most common viruses and their strains in East Africa are genetically unique and distinguishable from those occurring elsewhere in the world. The wild Ipomoea species in Uganda (other countries not yet studied) are infected with the viruses detected in sweetpotato crop. There are apparently also viruses that remain to be characterized. The RNaseIII enzyme of SPCSV eliminates antiviral defence of sweetpotato plants, following which they succumb to SPVD when infected with other viruses. An international research and education network including Uganda, Tanzania, Kenya, Finland, Sweden, Nicaragua, South Pacific, China and Peru (the International Potato Center, CIP) has formed to study sweetpotato viruses. Five PhD theses have been prepared and two PhD students from East Africa currently work in applicant’s laboratory. Ccomprehensive knowledge on viruses infecting sweetpotatoes in East and South Africa have been gained. Sustainable solution to the virus problems requires that farmers have access to healthy planting materials and SPVD-resistant cultivars. The aim of this study is to provide a comprehensive understanding of viruses in the wild Ipomoea species and their role as sources of new virus strains infecting sweetpotatoes and to detect as yet uncharacterized viruses in sweetpotato using novel, efficient methods and approaches. We also aim to develop means to inhibit the RNaseIII enzyme of SPCSV. The new knowledge is expected to help solving the prevailing, and foreseeing and preventing future virus problems in cultivated sweetpotato and assisting the regional programmes working on healthy plant production schemes and resistance breeding. Human capacity building carried out in the project focuses on modern skills for studying and solving virus disease problems in subsistence crops. It will not only benefit Tanzania and Uganda but the region more broadly, and also contributes to development in Nicaragua via enhanced international networking of the institutes involved.
|Gällande start-/slutdatum||01/01/2010 → 31/12/2013|
- Unknown funder: 400 000,00 €