Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2003
Publication Date: June 1, 2003
Citation: Gillaspie, Jr., A.G. New method for screening cowpea germplasm for resistance to cucumber mosaic virus (cmv). Phytopathology, 2003. Phytopathology 93:529 (2003). Technical Abstract: Utilizing cowpea (Vigna unguiculata (L.) Walp.) Germplasm line, GC-86L-98, a greenhouse screening method was developed to find potential sources of CMV resistance in the USDA cowpea germplasm collection. GC-86L-98, the first CMV-resistant cowpea germplasm line, was released by ARS in August 2001. A uniform source of CMV inoculum (freeze-dried cowpea tissue) was diluted to give an infection rate in GC-86L-98 similar to that observed under field conditions. More concentrated inoculum caused infection in all of the plants. Seedlings of cowpea test lines as well as GC-86L-98 and susceptible cultivar, Coronet, (both lines were included for comparison in each test) were mechanically inoculated and tested individually by DAC-ELISA after 2 weeks. In another test, the plants were sampled with a number 10 core borer, the leaf disks were combined in groups of 3 to 5 disks for ELISA, and the absorbance readings averaged for each test line. These averaged results did not always correlate with the percent infected numbers. The greenhouse percent infection screening method was used since it gave results most similar to those in field tests.