Studies on Genetic Diversity and Variability in Rice (Oryza sativa L.) Genotypes

The present investigation was carried out to evaluate the extent of genetic diversity and variability existing among the twenty two fine grain rice genotypes under study for eight significant yield attributes. Genetic diversity analysis based on D2 values suggested the grouping of 22 genotypes into eight clusters with genotypes in varying numbers. The biggest cluster, Cluster I, consisted eight genotypes succeeded by cluster II with 5 and cluster III with 3 genotypes. Distance within cluster was maximum in cluster V followed by the clusters II, III and I. Cluster III showed highest inter-cluster distance with cluster VII and cluster VIII. The traits single plant yield, grains per panicle, plant height and spikelet fertility contributed 94.8 per cent towards total divergence. Hence, these characters warrant maximum attention in hybridization programme and also during selection in the segregating generations. Simple selection procedures may be employed for characters viz., single plant yield, productive tillers per plant, filled grains per panicle and hundred seed weight with high and moderate extent of PCV and GCV. The characters single plant yield, filled grain per panicle and hundred seed weight showing the prevalence of high heritability along with high genetic advance as per cent of mean which reveals the presence of additive genetic effect.