A cowpea strain identified by Agricultural Research Service scientists could give rise to new commercial cultivars with resistance to cowpea stunt disease.
Cowpea stunt is caused by two viral "cohorts:" cucumber mosaic virus (CMV) and blackeye cowpea mosaic virus (BICMV). In Georgia, South Carolina, Alabama and other states, about 1.5 million acres of cowpeas are grown for human consumption, silage or green manure. Worldwide, cowpeas rank among the top five food fiber crops, since they can tolerate poor, dry soils. In some U.S. cultivars, severe cowpea stunt outbreaks can cause losses of up to 86%.
Breeding stunt-resistant cowpeas has proven difficult, and controlling the disease with pesticides isn't economical. ARS plant pathologist Graves Gillaspie and assistant curator James Chalkley hope to remedy the situation with the cowpea germplasm line GC-86L-98.
Now, plant breeders can grow GC-86L-98 in plots as a germplasm resource for passing stunt-resistance genes into elite commercial cultivars. Its heritage can be traced to PI 441918, a cowpea collected from a Brazilian marketplace, in 1978. Samples were later sent to the ARS Griffin lab and maintained there as part of a national cowpea germplasm collection.
GC-86L-98, which represents the ARS scientists' top selection of stunt-resistant plants from the Brazilian cowpea, produces large, tasty white seeds, Gillaspie says.
ARS is the U.S. Department of Agriculture's primary scientific research agency.