Cowpea (Vigna unguiculata) is a crop of major importance to the nutrition of poor rural households in the drier and sub-humid regions of Eastern and Southern Africa, where diets tend to be overly reliant on starchy foods such as millet, sorghum, maize and cassava. Cowpea grain is an inexpensive, high quality source of protein and its vitamin-rich leaves are eaten as spinach. Women particularly value cowpeas, which help them to bridge the "hunger months" prior to the main cereal harvest.
On-farm cowpea yields are extremely low, averaging 319 kg/ha in Tanzania and 388 kg/ha in Malawi. Use of late maturing cultivars, low plant density and insect damage are widely recognized as important constraints to improved cowpea production under on-farm conditions. Less well appreciated is the growing importance of the parasitic weed Alectra vogelii, which attaches itself to the roots of cowpea plants and interferes with the plants' ability to obtain water and nutrients. Recently-released improved cowpea cultivars that are earlier maturing and more tolerant of key insect pests and disease are especially susceptible to Alectra attack, experiencing up to 50% yield reductions.
A. vogelii is widespread from the Northern Province of South Africa, through Central Africa to Kenya and across West Africa to Mali. In Tanzania, A. vogelii is common in Mwanza, Shinyanga, Dodoma, Ismani and Ruvuma regions, while in Malawi, it is common in Lilongwe, Dowa and districts in central Malawi, the lower lying, drier areas of the southern region and the Blantyre/Shire Highlands.
This project will develop and promote Alectra-resistant cowpea lines that are acceptable to farmers and consumer markets in both Malawi and Tanzania. The project will link to the successful cowpea breeding program at the International Institute of Tropical Agriculture (IITA) to obtain sources of parasite resistance. Hybridization and selection, using backcross and pedigree breeding methods, will be undertaken to introduce parasite resistance into locally adapted, early maturing, high yielding, pest and disease resistant lines. The most promising lines will be provided to farmer groups with Alectra-infested land to be evaluated using participatory variety selection methods. The variability in virulence of A. vogelli strains obtained from throughout the region will also be determined so that resistant lines can be confidently deployed over wide geographic areas. Involvement of agricultural service providers and farmers will increase their understanding of cowpea production constraints, as well as opportunities for increasing productivity. The experienced farmer research groups will provide foci for scaling-up the multiplication and use of the varieties developed.