Asessment of genetic variation and relationships within the varieties of four Brassica species by RAPD markers

This investigation was aimed at exploring the genetic diversity and relationship among nine Brassica varieties of four different species using Random Amplified Polymorphic DNA (RAPD) markers. In total, 59 reproducible DNA bands were generated by four arbitrarily selected primers, of which 58 bands were proved to be polymorphic. These bands have had range from 212 to 2272 bp in size. The highest proportion of polymorphic loci (37.29 %) was found in BARI sarisha-12 (B. rapa) and the lowest was 8.47 % for both in BINA sarisha-4 (B. napus) and Rai-5 (B. juncea). The highest intra-varietal similarity index was found in Alboglabra while the lowest value was found in BARI sarisha-12 which suggested that the former one is the least diversified variety and the later is the most diversified variety among the studied varieties. UPGMA cluster analysis indicated that nine accessions were capable of being classified into two major groups. One group consists of BARI sarisha-12, Agrani and Sampad of B. rapa (2n =20, AA); Daulot and Rai-5 of B. juncea (2n =36, AABB) and Alboglabra (B. oleracea, 2n =18 CC) where Daulot and Rai-5 showed the lowest genetic distance of 0.049. Another group contains BINA sarisha-4, BINA sarisha-5 and BARI sarisha-13 all of which represent B. napus where BINA sarisha-5 and BARI sarisha-13 showed genetic distance of 0.071. The highest level of genetic distance was found between the varieties of BINA sarisha-4 and Rai-5 followed by the varietal pairs BINA sarisha-4 and Daulot.