Genetic Variability, Heritability and Selection Potential of Seed Size and Associated Traits among Cowpea Populations Developed Through Marker-assisted Backcrossing

Abstract

Background: Cowpea [Vigna unguiculata (L.) Walp.] production, in sub-Saharan Africa is severely limited by the parasitic weed Striga gesnerioides. Methods: This study assessed genetic variability, heritability and genetic advance for key agronomic and seed traits in F2 and BC1F1 cowpea populations developed through marker-assisted backcrossing (MABC) to combine Striga resistance with large seed size. Fifteen quantitative traits, including plant height, canopy diameter, seeds per pod and 100-seed weight, were evaluated across maternal half-sib families. Result: Analysis of variance (ANOVA) showed highly significant (P≤0.001) differences among genotypes for all traits, confirming substantial genetic variability among the population. Phenotypic coefficients of variation exceeded genotypic coefficients, indicating minimal environmental influence. Broad-sense heritability was high (93.33-100%) and several traits displayed high genetic advance, suggesting predominance of additive gene action and suitability for early-generation selection. Canopy diameter, pods per plant, seeds per pod and 100-seed weight emerged as reliable selection traits. Overall, MABC effectively integrated Striga resistance with desirable agronomic characteristics.