MOLECULAR DIVERSITY IN RICE GENOTYPES DIFFERING IN PHYSIOLOGICAL MECHANISMS OF SALT TOLERANCE THROUGH SSR AND ISSR MARKERS

摘要

Two different DNA-based techniques viz,simple sequence repeat (SSR) and intersimple sequence repeat (ISSR) markers were used to estimate genetic diversity among 20 ricegenotypes possessing different physiological mechanisms contributing to salt tolerance. A totalof 11 clear and repeatable bands were amplified from ten selected SSR primers pairs and 43fragments were detected from nine ISSR primers. The level of polymorphism was 1.1% withSSR compared to 90.7% with ISSRs. Mean genetic similarity of 0.88 based on SSRs and 0.85using ISSRs was observed. A total of 43 (39 polymorphic) and 11 bands were detected using 9ISSR primers and 10 well distributed mapped SSR markers, respectively. Estimates of geneticsimilarity of ISSRs based on the 39 polymorphic markers between 20 rice cultivars ranged from0.55 for PR108/CSR19 to 0.94 for Pokkali/CSR20 with an average of 0.81. The estimatesrevealed by the 11 polymorphic SSR bands showed the average value (0.94) and also the rangeof genetic similarity (from 0.86 to 1.00 for CSR22/CSR18 and CSR24/CSR20, respectively)reflecting their hyper variability and their high resolution power. The findings are likely toexpedite breeding new salt tolerant cultivars by involving parents from diverse molecularclusters