Genetics of Host Reaction in Cowpea to Cowpea Yellow Mosaic Virus and Cowpea Mottle Virus¹

Inheritance studies in cowpea ( Vigna sinensis (L.) Savi ex Hassk.) showed that three additive loci were responsible for tolerance to cowpea yellow mosaic virus and that the tolerant variety ‘Alabunch’ was probably homozygous for the three genes. Resistance to cowpea yellow mosaic virus was isolated in a selection from the variety ‘Dixielee’ and was found to be dominant to susceptibility and due to a single gene segregating independently of the loci determining tolerance. Tolerant and several classes of susceptible phenotypes were observed when the gene for resistancewas homozygous recessive. Tolerance to cowpea mottle virus was dominant to susceptibility, with either one or two genes responsible for the observed segregation, depending on the parents studied.