Genetic divergence studies in rice (Oryza sativa L.)

Sixty four rice germplasm lines were evaluated to study the degree and magnitude of genetic diversity by using Mahalanobis D2 technique. Based on genetic distance values all the genotypes were grouped into eight clusters. Cluster I was the largest one with 23 genotypes followed by cluster V with 11 genotypes and clusters II and VIII (8 genotypes). The trait days to 50% flowering contributed maximum towards genetic divergence followed by iron content, grain yield per plant, gel consistency and test weight. Cluster I had highest mean values for days to 50% flowering, number of tillers per plant, number of panicles per plant; cluster VI had highest mean values for grain dimensions and chemical quality traits, while cluster VII recorded higher values for hulling, milling, head rice recovery, volume expansion ratio and lesser values for kernel breadth and kernel breadth after cooking which are desirable. Grain yield per plant was highest in cluster IV which was separated by higher distance from clusters III and VIII.