Assessing genetic variation and trait associations in cowpea (Vigna ungucuilata (L.) (Walp.) genotypes for yield optimization

The study was conducted at the Horticultural College and Research Station, Vegetable Science Department of TNAU, Coimbatore. Thirty cowpea genotypes, including 2 check varieties, were used to measure genetic variation, heritability and the genetic improvement across 13 key traits. The results suggested that for all traits, phenotypic variation exceeded genotypic variation, indicating that environmental factors played a dominant role in the observed variation. Genetic diversity was observed from the GCV values for several traits. These traits are associated with high heritability and significant genetic improvement, especially for characters such as pod weight, per plant pod yield and pod length, which are mainly controlled by additive genes; thus, they are suitable for use in breeding program to improve yield. The important trait in selecting high-yield cowpea varieties is shown by the strong positive genetic resemblance between the per pod seed number and per plant pod yield. PCA identified 5 main components that showed 77.53 % of the total variation. Traits with positive values in each component were considered the most important for yield, making them key factors for selecting high-yielding cowpea varieties.