Relationship of Cowpea Seed-Part Infection and Seed Transmission of Blackeye Cowpea Mosaic Potyvirus in Cowpea

Blackeye cowpea mosaic potyvirus (BICMV) 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 BICMV by DAS-ELISA and by bioassay on Chenopodium amaranticolor. Viruses occurred in cotyledons and/or embryo axes in Coronet 1985cs, Coronet 1986cs, and PI 517912 but only in the cotyledons in Coronet 1987. Viral antigen was found in or on the testae, but very little infectious virus was present. The germinability of cowpea seeds of five accessions that were hydrated, decorticated, and stored 12 wk ranged from 60 to 100%