Morpho -genetic variability in F 2 progeny cowpea genotypes tolerant to bruchid (Callosobruchus maculatus)

Abstract

Callosobruchus maculatus Fab. is a major threat to cowpea production reducing the quality, quantity and market value of cowpea grains. A cheap and easy identification method would be a valuable tool in identifying and breeding resistant genotypes in the vast cowpea germplasm. Hence, the purpose of the study was to identify and evaluate the genetics of cowpea traits between resistant and susceptible plant genotypes to C. maculatus. Contrasting qualitative and quantitative traits in C. maculatus resistant and susceptible parents were evaluated in 72 F 2 progeny cowpea plants. Heritability, segregation and association of investigated traits with the C. maculatus resistant performance of the F 2 cowpea genotypes were evaluated to determine closely related traits with C. maculatus resistance. Results from the study showed high heritability for all cowpea quantitative traits except leaf petiole length. Both Mendelian inheritance and non-Mendelian inheritance were observed among qualitative traits. However, association evaluation between cowpea traits and mean bruchid development period, percentage adult emergence and oviposition preference were weak (r < 0.5) and not significant (p < 0.05). This indicates that C. maculatus resistance in cowpea may be attributed to factors other than morphological variations.

Keywords

• callosobruchus
• cowpeas
• variability
• susceptibility
• resistant
• morphology