Genetic divergence in upland rice (Oryza sativa L.)

Abstract

Genetic diversity was assessed in 40 genotypes of rice for 12 quantitative characters including grain yield using Mahalanobis D2\rstatistics. The D2 values between all possible pairs of 40 genotypes ranged from 26.32 to 404.814. The results revealed that 40\rgenotypes were grouped into 8 clusters with substantial divergence between them. Cluster I was very large comprising 24 genotypes\rfollowed by cluster II with 10 genotypes, while clusters III to VIII were solitary clusters. The maximum inter-cluster distance was\robtained between cluster VI and VII (D = 20.12) followed by those between cluster VII and VIII (D = 18.56) which may serve as\rpotential parents for hybridization, whereas, minimum between cluster III and IV (D = 5.13). The highest intra cluster distance was\rrecorded for cluster II (D = 7.96) and lowest for cluster I (D = 6.62). The genotypes in the cluster VI had lowest mean value (89.67)\rfor days to 50 per cent flowering indicating their use in breeding program for development of early maturing varieties. Cluster VIII\rrecorded high grain yield per plant showing its potential for yield improvement. The characters number of spikelets per panicle and\rdays to 50 per cent flowering contributed maximum in the manifestation of genetic divergence. RDN-20, RDN-11, Phule Radha,\rRDN-18 and RDN-5 may serve as potential donors for future hybridization programmes