Reaction of Cowpea Introductions to Infection with the Cowpea Strain of Southern Bean Mosaic Virus. S. K. O’Hair, Graduate Assistant, Department of Horticultural Sciences, Texas A&M University, College Station 77843. J. C. Miller, Jr., Associate Professor, Department of Horticultural Sciences; and R. W. Toler, Professor, Department of Plant Sciences, Texas A&M University, College Station 77843. Plant Dis. 65:251-252. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-251.

In field and greenhouse studies, 1,029 introductions of cowpea were evaluated for reaction to infection with the cowpea strain of southern bean mosaic virus (SBMV-CS). The expression of wide genotype-specific variability for reaction to SBMV-CS infection was, in part, influenced by season. Symptom groups identified and proportion of plants in each group were: mosaic (81%), vein clearing (21%), leaf distortion (18%), stunting and dwarfing (16%), chlorosis (12%), distinct chlorotic spots (2%), early senescence (2%), generalized necrosis (1%), necrotic local lesions (1%), and spindled plants (0.2%). Distinct chlorotic spots, entire leaf chlorosis, generalized necrosis, and spindling plants have not been previously reported in association with SBMV-CS infection. Levels of field tolerance were high, in the form of symptomless carriers. Seed transmission ranged from 0 to 25%; most entries had less than 10%.

Keyword(s): southern pea, Vigna unguiculata, Vigna sinensis.