Genetic variability and diversity in indigenous rice germplasm of Assam under aerobic condition

An investigation was carried out to study genetic variation and diversity pattern in a set of 80 rice genotypes of Assam grown under aerobic environment. Amongst the 11 traits under study, highest genotypic coefficient of variation was exhibited by grain yield, followed by 100 grain weight and grain L:B ratio. Heritability in broad sense was highest for grain L:B ratio followed by grain width and grain length. More than 90% heritability in broad sense was, however, observed for all other traits except effective tillers per plant panicle length and grain yield. Genetic advance as per cent of mean was observed highest for grain yield followed by 100 grain weight and grain L:B ratio. It was, thus predicted that selection for these traits would be most effective for further genetic improvement.. At the intermediate linkage distance, we obtained twelve diverse clusters out of the 80 entries following Euclidean cluster analysis. The cluster II was the largest consisting of 61 genotypes followed by cluster IV with seven and cluster I, III, V and XI with two genotypes each. All other clusters were monogenotypic. Based on the coefficient of variation it may be assumed that filled spikelets per panicle followed by plant height and days to maturity contributed mostly to the total diversity. Considering the mean performance of genotypes, and their distribution in diverse clusters genotypes were identified as parents for hybridization programme to incorporate desirable values of the traits under investigation. The above findings, thus, would be useful for planning a comprehensive hybridization programme for obtaining desirable segregants for selection of improved genotypes under aerobic situation.