Analysis of Genetic Diversity in Brassica juncea (L.) Varieties by Using RAPD and ISSR

Brassicajuncea L. (family: Brassicaceae), is an important oilseed crop and known to be anodyne, aperitif, diuretic, emetic, rubefacient, and stimulant. In the current investigation RAPD and ISSR primers were used to assess genetic diversity in its 15 varieties. Total genomic DNA was extracted by CTAB and PCR amplification was carried out. Out of 100 tested RAPD primers, 60 primers were amplified, of which 43 were used for scoring and 42 revealed polymorphic loci. The number of bands amplified per primer varied between 2(OPD 9) and 19 (OPD-20) with an average of 6.09 bands per primer. A total of 256 bands were amplified of which 157 were polymorphic resulting in a polymorphism frequency of 61.32% and an average of 3.8 polymorphic bands per primer. Out of the 100 UBC tested ISSR primers, 48 primers gave amplification. Of these 31 primers were used for scoring. 30 primers gave polymorphic bands while 1 primer was monomorphic. The number of amplicons per primer ranged from 5 (UBC 830) to 19 (UBC 810 and UBC 840). The polymorphic primers amplified 321 bands of which 189 were polymorphic resulting in a polymorphic frequency of 58.87% and an average of 6.3 polymorphic bands per primer. The dendrogram revealed two main clusters. Each cluster was subdivided into subgroups. The present investigation revealed that molecular markers could be successfully utilised to determine genetic diversity and genetic relationship of various varieties. From the clustering pattern and genetic relationship obtained with different markers, breeders can fruitfully identify the diverse genotype from different cluster and take them up in their future breeding program.