Blackeye Cowpea Varietal Improvement for California and the USA Focused on Biotic Stress Resistance.

Cowpea (Vigna unguiculata L. Walp) is a nutritious food legume crop grown in sub-Saharan Africa and other warm-to-hot regions worldwide. In the United States, including the Central Valley of California, cowpeas are grown as blackeyes or black-eyed peas for dry-grain production and soil nitrogen fixation for following crops in rotations. Aphids, lygus bug, root-knot nematodes and fusarium wilt disease are prevalent in this region, in part due to the large-scale production of cotton and alfalfa, causing significant reductions in yield and seed quality of current blackeye cultivars. The California dry bean industry together with the USAID Feed the Future Innovation Lab for Collaborative Research on Grain Legumes supports our program to develop improved blackeye varieties for California and the USA. Sources of genetic resistance to the aforementioned biotic stresses were found in African cowpea germplasm and are being bred into susceptible blackeye cultivars using both conventional and molecular breeding strategies. Advanced breeding lines with stacked resistance loci were developed and are being evaluated in on-station and commercial field trials for cultivar release potential. The genetic loci conferring biotic resistance discovered in the US can also be used in African cowpea improvement in production areas that share common biotic stress species and biotypes.