Diversity analysis for yield traits and sheath blight resistance in rice genotypes

Genetic diversity play a crucial role in crop improvement as progeny from divergent parents show greater heterosis and provide a wide range of variability in segregating generation. It also provides a chance to obtain new recombination of genes in the gene pool. The present study was conducted with 29 genotypes and observations were recorded for plant height, the number of tillers/plant, the number of productive tillers/ plant, panicle length, grain number/panicle, test weight and grain yield/ plant. Genetic divergence among the genotypes was estimated by Mahalanobis D2 analysis. The genotypes were grouped into six clusters. The maximum number of genotypes (eight) was found in cluster 4, followed by seven in cluster 2, six in cluster 3, four in cluster 1, three in cluster 5 and one in cluster 6. Maximum intra-cluster D2 value was recorded in cluster 4 (166.93) and minimum in cluster 6 (0.00). The D2 value of inter-cluster ranged from 204.20 to 1861.92. Maximum inter-cluster D2 value was found between cluster 4 and 5 (1861.92), followed by cluster 5 and 6 (1548.42). It indicated a very wide range of genetic diversity among genotypes. These genotypes may be utilized for the hybridization programme for sustaining rice production. Moreover, from this study, we also recommend crossing of genotypes belong to cluster 5 and two genotypes of cluster 4 (Ngonolasha and Phougak) for developing high yielding genotype with sheath blight resistance.