Genetic variability and correlations of agronomic characters in cowpea (Vigna unguiculata)

Cowpea (Vigna unguiculata (L.) Walp) is an important food crop for human population in northeastern Brazil. Studies aiming to increase its yield as well as to improve the grain quality and the insect and diseases resistance are needed. This work aimed to accomplish genetic studies in twenty-eight cowpea advanced lines. The studied lines were chosen after selection for seed color and size and plant viruses resistance. The degree of genetic determination ranged from 4.51% (in pods/peduncle) to 81.74% (in 100-seed weight). The seed yield degree of genetic determination was 34.15%. The highest estimates of genetic gain were 21.73% to 100-seed weight and 19.77% to seed yield. The genotypical correlations were higher than phenotypical and environmental ones. High correlations were found between fruiting branches/plant and seed yield (68.13%) and between agronomic value and seed yield (100%). This result indicates the selection feasibility for most of the studied traits.