Seed Protein Pattern of Cowpea (Vigna unguiculata L.) and Its Distant Species

Seed protein was extracted from two varieties of cowpea (CO 2, CO 6) and eight distant species of Vigna and was analysed by SDS-PAGE. The relative migration (Rm) and Similarity Index (SI) were worked out. There was no difference in protein profiles of varieties CO 2, a vegetable type cowpea and CO 6, a grain type cowpea (SI = 100%). A high SI has been exhibited by V. glabrescens with V. radiata (62.5%) and V. umbellata (45.4%), the probable progenitors of the natural amphidiploid V. glabrescens. V. sublobata and V. trilobata revealed greatest SI (90.9%) indicating a close evolutionary relationship, on the contrary, V. mungo and V. umbellata exhibited a zero value revealing a greater evolutionary distance. The electrophoretic variability study indicates difficulty in obtaining interspecific hybrids through conventional methods for cowpea improvement (SI < 26.67%).