Cowpea [Vigna unguiculata (L.) walp.] seed proteins: Heterogeneity in total proteins and protein fractions

Eleven genotypes of V. unguiculata were screened for variability in total proteins and various protein fractions viz. albumins, globulins, prolamins and glutelins by using SDS-polyacrylamide gel electrophoresis. The electrophoretic pattern showed the molecular heterogeneity among total proteins as well as various protein fractions. The molecular weights of protein bands obtained by SDS-PAGE varied between 10 to 141.3, 15.85 to 147.9, 10 to 125.9, 7.94 to 56.23 and 10 to 79.43 kDa for total proteins, albumins, globulins, prolamins and glutelins, respectively. Most of the bands were common to the different genotypes indicating their close relationship with one another. However, a few bands unique to some particular genotypes were also observed showing the varietal differences. Cluster analysis based on total proteins and various protein fractions provided evidence for differences among the varieties collected from different agroclimatic zones of India. The observations revealed that seed protein polymorphism provides a useful information regarding variability among genotypes under investigation which could be helpful for breeding purposes in the improvement of protein quality and quantity in grain legumes.