Ag. Gillaspie, Resistance to Cucumber mosaic virus in cowpea and implications for controlof cowpea stunt disease, PLANT DIS, 85(9), 2001, pp. 1004-1005
Cucumber mosaic virus (CMV) and Blackeye cowpea mosaic virus (BlCNW) intera
ct synergistically in dually infected plants of cowpea (Vigna unguiculata s
ubsp. unguiculata) to cause cowpea stunt disease, the most damaging viral d
isease of this crop in the U.S. Sources of resistance to BlCMV are known an
d are present in cultivars of cowpea such as Pinkeye Purple Hull-BVR. Howev
er, no sources of CMV resistance have been found previously in cowpea. In 1
998, PI 441918, a cowpea line growing in regeneration plots, was observed t
o have few viral symptoms, was not infected with BlCMV, and had a low titer
of CMV when tested using direct antigen coating-enzyme-linked immunosorben
t assay (DAC-ELISA). In greenhouse tests, infection of PI 441918 with CMV r
esulted in a lower titer of virus if the inoculated plants were from white
seeds of PI 441918 than if the plants were from tan seeds of this PI, and a
lower titer of virus than plants of the susceptible cultivar Coronet. In t
he field, with CMV- and BlCMV-infected plants of Coronet in spreader rows,
plants from white seed of PI 441918 had no infection with BlCMV and a low i
nfection rate with CMV. PI 441918 offers a high level of resistance to BlCM
V and moderate resistance to CMV, which are important characteristics in a
parental line to develop cultivars of cowpea resistant to cowpea stunt dise
ase.