PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Seed physical traits are important determinants of yield-related attributes, seed appearance and consumer market preference in cowpea. The present investigation was conducted under Western Himalayan conditions to assess variability and trait associations for ten physical seed traits in 254 diverse cowpea genotypes, including four checks, and to identify promising lines for future breeding programmes. Considerable variability was observed across all studied traits, indicating substantial diversity among the evaluated genotypes. Seed length, seed breadth, seed width, breadth/width ratio and aspect ratio ranged from 5.33 to 11.67 mm, 3.87 to 9.80 mm, 3.03 to 18.60 mm, 0.87 to 2.13 and 0.30 to 2.31, respectively. The ranges for equivalent diameter, sphericity, seed volume and surface area also indicated clear phenotypic variation. Seed volume and surface area ranged from 25.17 to 256.17 mm³ and 46.01 to 196.59 mm², respectively, with mean values of 69.82 and 95.76. The coefficient of variation was highest for seed volume (38.39%), followed by 100-seed weight (34.05%) and surface area (25.97%), suggesting comparatively greater scope for selection in these traits. Correlation analysis showed positive associations among several seed physical traits. Seed length was positively correlated with seed breadth, aspect ratio, surface area, seed volume and equivalent diameter, while seed breadth was positively associated with seed thickness, breadth/thickness ratio, surface area, volume and aspect ratio. The first two principal components of the PCA biplot explained 80% of the total variation, supporting visual interpretation of trait relationships and their contributions to variability. These findings show that the cowpea core set contains useful variability for selecting genotypes with desirable seed physical traits.