GENETIC DIVERSITY ANALYSIS OF BRASSICA NAPUS/BRASSICA CAMPESTRIS PROGENIES USING MICROSATELLITE MARKERS

Abstract

Genetic diversity and relationship of F2 segregating progenies of interspecific crosses between B. napus N-501/B. campestris C-118 were studied. A set of 90 genotypes (2 parental lines and their 88 F2 progenies) was characterized separately using 24 microsatellite or SSR markers to cover the diversity as broadly as possibly present in them. In initial screening only 12 out of 24 SSR primers combination amplified DNA fragments, hile the remaining 12 SSR primers did not amplify DNA fragment therefore those 12 SSR molecular markers were not used for further analysis. The 12 SSR primer combinations generated a total of 33 alleles, of that 32 were polymorphic loci, whereas only one was monomorphic locus. Primers BRMS-19 and BRMS-40 were highly polymorphic producing 4 bands each. Primer Ra2-D04 was less polymorphic and it produced only one band. The proportion of polymorphic loci was 95.83% which indicates high genetic diversity among the progenies. The average number of polymorphic alleles per locus was 2.66. The PIC values ranged from 0.395 for primer Ra2-E03 to 0.726 for primer BRMS-019 with an average genetic diversity (PIC value) of 0.584 per locus. Seven primers showed PIC values above 0.5 (50%) indicating high genetic diversity in the studied plant materials. Pair-wise similarity indices among 90 genotypes ranged from 0.3 to 0.95. Dendrogram obtained through UPGMA clustering of F2 progenies depicted eight main groups using similarity coefficient of 0.70. The progenies could be similar to their parents if they have the same banding patterns as that of the parents and could be distinguished from each other by the combination of fragments which are repeatedly present in one progeny and absent in the other. Considerable genetic diversity has been found among the F2 segregating progenies and their parents using SSR markers thus, SSR analysis proved to be a useful tool.