Assessment of Genetic Diversity in Four Brassica Species using Randomly Amplified Polymorphic DNA Markers

This investigation was aimed to explore the genetic diversity and relationship among the 30 Brassica varieties of four different species such as Brassica juncea, Brassica rapa, Brassica napus and Brassica carinata using RAPD markers. Forty primers were tested in this study, out of which 33 revealed clear and repeatable RAPD polymorphisms. They produced 530 total loci and the total bands were 6041. Out of the 530 loci produced, 511 were polymorphic and hence the total polymorphism percentage was found to be 95.96%. Nineteen primers out of 33 analyzed successfully produced 100% polymorphism. The average PIC value for RAPD was 0.92. The highest PIC value obtained was 0.94 for S-70 marker and lowest PIC value was 0.77 for S-40. The number of amplicons produced per primer varied from 9 to 26 with a mean of 16.56 bands per primer. The molecular size of the amplified PCR products ranged from 130 to 3100 bp. On the basis of dendrogram, thirty accessions were categorized mostly according to their species. Cultivar specific RAPD markers for fifteen accessions were also detected. The study revealed that the diversity exhibited by genotypes belonging to various Brassica species can be further utilized for crop improvement programme.