Genetic diversity analysis of direct seeded rice genotypes under drought situation

Genetic divergence is an efficient tool for the selection of parents used in hybridization programme. In the present study, Seventy six rice genotypes, landraces and popular varieties consisting of both indigenous and exotic collection were studied for yield and yield related traits. Based on D2 analysis, the genotypes were grouped into eight clusters. Maximum number of genotypes (35 genotypes) were grouped in cluster I. The maximum inter cluster distance was observed between cluster VI and VII (35.02) followed by between cluster III and VII (34.68) and between cluster I and VIII possessing wider genetic diversity among the genotypes between these groups. The hybrids developed from the selected members of these clusters would produce highly variable population in the segregating generations. The maximum intra cluster distance was observed in cluster III (6.46) followed by cluster IV (6.32). Hence, selection within these clusters may be exercised based on the highest areas for the desirable traits, which would be made use of in improvement through intervarietal hybridization. Among the twelve traits studied, kernel length contributed maximum divergence (34.32%) followed by plot yield (21.02%). Hence, the traits viz., sterility, plot yield, kernel length, kernel breadth, 1000 grain weight contributed 71.52 per cent towards total divergence. Therefore, these characters should be given importance during hybridization and selection in the segregating population.