Modern Cowpea Breeding to Overcome Critical Production Constraints in Africa

On-farm cowpea yields of traditional varieties in Africa are at least 5-fold lower than potential yields due in large part to several key biotic and abiotic stresses.  Development of cowpea cultivars that resist or tolerate these stresses is a particularly desirable strategy for this crop because it is grown mostly by resource-poor farmers, many of whom are women who lack access to capital. Breeding by several African National Research Systems (NARS), supported by USAID Collaborative Research Support Program (CRSP) projects over the past 25 years have successfully bred cultivars resistant to some of the key pests such as cowpea aphid, cowpea weevil, the parasitic weed Striga gesneroides and cowpea aphid-borne mosaic virus (CABMV) and raised on-farm yields, but additional and speedier gains are needed. The genomics revolution has enabled rapid advances in genotyping capabilities and construction of high-density genetic maps that facilitate new plant breeding strategies with the potential to expedite delivery of improved crop varieties. This talk will review past accomplishments of CRSP breeding efforts and how new genomic resources in cowpea are being harnessed to enable modern breeding by NARS in Africa. These resources include a 1536-SNP assay and conversion of SNPs to the KASPAR single-plex format, a genetic consensus map with 1107 SNP markers in 856 bins developed from genotypes of 1293 individuals in 13 mapping populations, and identification of trait-linked markers for resistance to bacterial blight, ashy-stem blight, foliar and flower thrips, root-knot nematodes and tolerance to drought.