RELATIONSHIP OF COWPEA SEED-PART INFECTION AND SEED TRANSMISSION OF BLACKEYE COWPEA MOSAIC POTYVIRUS IN COWPEA

Blackeye cowpea mosaic potyvirus (BlCMV) was seedborne in four cowpea seed lots (two genotypes) at incidences of 0.4-50%. Fully mature seeds were hydrated and separated into testae and embryos. Each embryo was separated further into two cotyledons and the embryo axis. These were tested separately for BlCMV by DAS-ELISA and by bioassay on Chenopodiu m amaranticolor. Viruses occurred in cotyledons and/or embryo axes in Coronet 1985cs, Coronet 1986cs, and PI 517912 but only in the cotyledo ns in Coronet 1987. Viral antigen was found in or on the testae, but v ery little infectious virus was present. The germinability of cowpea s eeds of five accessions that were hydrated, decorticated, and stored 1 2 wk ranged from 60 to 100%. Applicability of these data to the establ ishment of testing for seed-transmissible BlCMV is discussed.