Agro-morphological diversity and yield potential of Bambara groundnut ( <i>Vigna subterranea</i> L. Verdc.) recombinant inbred lines evaluated across multiple environments in KwaZulu-Natal, South Africa

Abstract Bambara groundnut ( Vigna subterranea L. Verdc.) is a resilient, nutrient-rich legume with significant potential for diversification in climate-resilient agriculture and food systems. However, its improvement has been limited by a lack of formal breeding programs and genetic characterization. This study evaluated the agro-morphological diversity of 44 recombinant inbred lines (RILs) and 10 check genotypes developed through single seed descent, assessed across three environments in KwaZulu-Natal, South Africa. Eleven quantitative and five qualitative traits were measured following BAMNET descriptors. Analysis of variance revealed significant genotypic differences (P &lt; 0.01) for most traits and strong genotype × environment interactions for seed length, seed width, grain yield, and related components. Principal component analysis (PCA) showed that the first three principal components explained over 72% of the total variation, with PC1 strongly associated with yield-related traits such as grain yield (GY), unthreshed grain yield (UGY), grain yield per plant (GYPP), and shelling percentage (SHLP). Cluster analysis grouped the genotypes into distinct clusters, separating high-yielding from low-yielding lines. Genotypes (G23, G39, G40 and P3) demonstrated superior yield performance and were identified as promising candidates for future breeding efforts. Correlation analysis highlighted strong positive associations between yield traits and seed size parameters, while early emergence and flowering were associated with higher germination rates. The findings demonstrate substantial genetic diversity among the evaluated Bambara groundnut genotypes and provide critical insights for developing high-yielding, climate-resilient cultivars. These results contribute towards positioning Bambara groundnut as a strategic crop aligned with the Vision for Adapted Crops and Soils (VACS) agenda, promoting food and nutritional security under changing climatic conditions.