Evaluation of Blackeye cowpea mosaic virus pathogenicity in soybean

Abstract

Ten soybean lines were investigated under screenhouse conditions for resistance to Blackeye cowpea mosaic virus (BlCMV) infection. The experiments were laid out in a completely randomised design with five replications. Seedlings were inoculated with the virus at 10 days after sowing by mechanical transmission. Observations were made on percentage disease incidence, symptom severity, growth and yield parameters. Symptom scores were subjected to Area Under Disease Progress Curve (AUDPC) while other parameters were subjected to analysis of variance (ANOVA) at 5 % probability level. All the inoculated plants exhibited disease symptoms (100 %) but AUDPC identified soybean line TGX 2007 - 1F as the most tolerant to BlCMV infection. Among the BlCMV-inoculated plants, highest seed weight (4.7 g per plant) was produced by TGX 1990 – 46F; which also had the lowest seed weight reduction (55.3 %). The genotype TGX 1990 – 46F which produced the highest seed yield under BlCMV infection pressure could be subjected to further yield trials and selected for cultivation in the absence of resistant varieties.