Background: Cowpea [Vigna unguiculata (L.) Walp.] production, in sub-Saharan Africa is severely limited by the parasitic weed Striga gesnerioides. 
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Methods: This study assessed genetic variability, heritability and genetic advance for key agronomic and seed traits in F2&nbsp;and BC1F1&nbsp; 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. 
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Result: Analysis of variance (ANOVA) showed highly significant (P&le;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.

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