Disease-Resistant Cowpeas Now Available
By Jan Suszkiw
October 9, 2001
A cowpea strain identified by
Agricultural Research Service scientists
could give rise to new commercial cultivars with resistance to cowpea stunt
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 percent.
Breeding stunt-resistant cowpeas has proven difficult, and controlling the
disease with pesticides isnt economical. ARS plant pathologist Graves
Gillaspie and assistant curator James Chalkley hope to remedy the situation
with the cowpea germplasm line GC-86L-98.
Their enthusiasm stems from trial results since 1998 showing it resists CMV,
and is immune to BICMV. By resistant, Gillaspie explains, the plant
can still flower and bear seed despite some late-season CMV infection. In
susceptible cultivars, like Coronet, symptoms can include stunted growth,
yellow, curled leaves and poor seed yield. GC-86L-98 is immune to BICMV because
no infection occurs, adds Gillaspie, with ARS
Resources Conservation Unit in Griffin, Ga.
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. Seed requests can be e-mailed to him at
email@example.com, or submitted via the
National Plant Germplasm System website at:
ARS is the U.S. Department of
Agricultures primary scientific research agency.