Identification of some cowpea accessions tolerant to Cowpea mild mottle virus

Abstract

Five locally adapted cowpea accessions, as well as a susceptible control variety Ife Brown were evaluated under screen house conditions for resistance to Cowpea mild mottle virus (CPMMV). The experiments were arranged in completely randomised design with four replicates. Seedlings were inoculated at the three-leaf-stage, while uninoculated plants of each genotype served as negative controls. Virus concentration was quantified by enzyme-linked immunosorbent assay (ELISA). Disease incidence, severity, yields and agronomic traits were recorded. Generally, uninoculated control plants performed better than the inoculated. Three genotypes (IT07K-251-3-3, IT07K-299-4 and IT07K-299-6) were rated as partially tolerant, whereas the remaining ones were susceptible. The yield and growth attributes of the partially tolerant plants were not significantly (p>0.05) different from their healthy uninoculated counterparts. The most tolerant accession (IT07K-299-6) exhibited the lowest reduction in leaf area (0.7 %), plant height (7.3 %), seed weight per plant (2.3 %) and virus concentration (0.11 – 0.247). These results suggest that the partially tolerant accessions most likely contain genes that confer tolerance to CPMMV and could be useful in cowpea breeding for genetic improvement.