Gains in genetic enhancement of early maturing advanced breeding lines of cowpea [Vigna unguiculata (L.) Walp]

Abstract

The objective of this study was to determine genetic potentials in extra-early maturing lines of cowpea. Sixteen early and extra-early maturing lines and their recurrent parents were evaluated at Nyankpala and Manga in the Guinea and Sudan savannah ecologies of Ghana, respectively during the rainy season of 2021 main cropping season. Data were collected on the key earliness-related traits, yield, and yield components. The results showed significant differences for genotypes (G) and locations (L). A hierarchical cluster on principal component analysis grouped the genotypes into super-early (≤55 days after sowing, DAS), extra-early (55–60, DAS) and early maturing (61–70, DAS). Within the extra-early maturing cluster, box plot analysis revealed that 75 % of the lines had high grain yield (≥2 t/ha) at Nyankpala, whilst 50 % of them had ≥1.8 t/ha at Manga. The study identified breeding lines which have key farmer preferred traits such as extra-early maturing, high grain yield, and large seed size. Five genotypes (SAC-20KTE-5, SAC-20KTE-3, SAC-20KTE-29, SAC-20KTE-6, and SAC-20KTE-7) were statistically higher than the parental lines, in terms of grain yield, number of days to maturity (≤60 DAS) and hundred seed weight (≥20 g). There was no trade-off for grain yield, biomass yield, and seed size in the selected early maturing lines. Potential lines identified from the study should be extensively evaluated at multi-locations and superior ones released to mitigate the effects of terminal drought and other stresses for cowpea production in the sub-region.