Intra-specific genetic divergence in rapeseed (BRASSICA NAPUS L.) genotypes estimated through SDS-PAGE of total seed proteins

Abstract

Through biochemical technique of SDS-PAGE, 136 genotypes of rapeseed (Brassica napus L.) were characterized based on total seed storage proteins. The germplasm used in the study consisted of 135 accessions and one check cultivar obtained from Gene-bank of Plant Genetic Resources Institute (PGRI), NARC, and Islamabad, Pakistan. During this study 12.25% polyacrylamide gels were used and a total of 21 protein sub-units were observed among the genotypes. Out of these 21 bands, 16 (76.19%) were polymorphic and the rest of 5 (23.81%) were monomorphic. The 21 protein sub-units were found within the range of molecular weights from 6 to 180 kDa. The similarity coefficient among these genotypes ranged from 0.83 to 0.98. The genotypes studied were divided into five major clusters through constructing the dendrogram on the basis of dissimilarity matrix using UPGMA (unweighted pair group method with arithmetic averages). Overall a low level of genetic divergence was found. So, it is suggested that to find out high level of genetic diversity among these genotypes 2-D gel electrophoresis along with other modern techniques should be practiced in future because SDS-PAGE technique alone is insufficient to fully explore the genetic diversity present in these genotypes. Keywords : SDS-PAGE; Genotypes; Brassica napus L.; Polymorphic; Monomorphic; Electrophoresis; UPGMA.