Microsatellite (SSR) markers assisted characterization of rice (Oryza sativa L.) genotypes in relation to salt tolerance

Under present investigation a total of 18 rice genotypes with diverse genetic background were taken for screening at seedling stage and its molecular characterization using SSR markers. Selected rice genotypes were exposed to five salinity levels (0, 2, 4, 6 and 8 dSm(-1)) at seedling stage. Modified standard evaluation score (SES) at seedling stage identified 7 highly tolerant, 2 tolerant and 8 moderately tolerant genotypes. The susceptible genotype was IR64 with score 7. Considering 4 other morpho-physiological characters (germination percent, K/Na ratio, shoot and root length, shoot and root fresh weight, shoot and root dry weight) studied at seedling stage, the genotype CSR2K-262 showed greater tolerance among all the 18 genotypes. For molecular characterization a total of 44 SSR markers were selected. The average number of alleles per locus was 9.3 indicating greater magnitude of diversity among plant materials. The average PIC value 0.767 confirmed that the markers used were highly informative. The cluster analysis grouped the 18 genotypes into three major clusters. Cluster I was the largest with 9 genotypes with all highly tolerant and tolerant genotypes, Cluster II comprised 8 genotypes with all tolerant and moderately tolerant and Cluster III comprised of 1 genotype (IR64) identified as susceptible one.