Phenotypic and protein variations among selected cowpea (Vigna unguiculata L. Walp.) varieties

The study seeks to evaluate the level of genetic diversity among selected cowpea varieties using both phenotypic traits and seed storage proteins. Twenty cowpea varieties were used in the study. They were planted and phenotypically characterized. Seed proteins were evaluated at maturity. There was a high phenotypic variation observed among the selected cowpea with the evaluated phenotypic traits while a low level of variation was observed with protein evaluation. The variation captured by the phenotype (>90%) was higher as compared to the protein (< 30%) analysis in the study. Three major clusters were generated with the majority of the germplasms in cluster III, regardless of whether the phenotype or protein analysis was used. While the variation observed within the phenotypic traits might have been due to environmental influences, the low variation exhibited using seed storage proteins implies a high level of similarity among cowpea samples. Hence, a more stable marker type should be explored to identify the true level of genetic diversity within cowpea germplasm.