E. Punitha and T. Sabesan
Abstract
The present research consists of 21 rice genotypes investigated to assess the extent of genetic divergence using principal component analysis. The principal component analysis (PCA) revealed that out of eleven quantitative traits, five most informative PCs with Eigen values of 3.55, 1.83 and 1.28 which accounted for 74.20% of the cumulative variance. Accordingly, based on the relationship of characters and genotypes to the PC 1, it can that the genotypes AUI GSR, Dayala Modina, BA 132, ADT 43 and ADT 44 can be selected for above said characters for breeding purposes in yellow stem borer resistance. Furthermore, selected 6 rice genotypes were analyzed to evaluate the genetic polymorphism and identification of stem borer resistance through SSR markers. A total of 51 alleles were detected from 15 polymorphic markers with an average of 2.55 alleles per polymorphic marker. The marker RM 7405, RM 566, RM 6467 and RM 6471 produced maximum 4 alleles. The PIC values reflected the level of diversity and allelic frequency among the varieties which varied widely among SSR loci ranged from 0.287 to 0.994. The marker RM210 was found to be the most appropriate marker to discriminate among the rice genotypes owing to the highest PIC value of 0.994. The cluster analysis exhibited that these genotypes grouped into two clusters, in which cluster II had 5 genotypes followed by cluster I. The combination of morphological diversity and molecular genetic diversity studies clearly show the AU1 GSR, ADT 43, ADT 44, BA-132 and Dayala modina as new sources of stem borer resistance. These genotypes could be exploited in the future crop breeding programme to develop resistant varieties against the rice yellow stem borer.