Abstract

Rice (Oryza sativa L.) is one of the most important staple cereal food crop and a source of calories for more than half of the world’s population. Genetic diversity in the world rice germplasm is larger but only small collections have been used in breeding programs since a high genetic similarity is found within germplasms around the world. An investigation was carried out at Tamil Nadu Rice Research Institute, Aduthurai during kuruvai 2009 with 31 rice germplasm accessions of which 16 accessions were of Indian origin and remaining 15 accessions were exotics with the objective of studying genetic diversity through mahalanobis D² statistics. Observations recorded were related to Distinctiveness, Uniformity and stability (DUS) test and eleven yield attributing measures. Accessions were grouped into 13 clusters. The cluster I contained highest number of accessions (6) followed by cluster X, XI which had three genotypes each, where cluster XIII had only one accession. The intra cluster distance was highest in cluster X (12.11) followed by cluster XII (12.01). Highest inter cluster distance was noticed between clusters II and X (24.84) followed by clusters X and XIII (20.83), and lowest between clusters V and IX (6.14). Single plant yield contributes to 45.16% and hundred grain weight contributes to 17.20% of the total genetic divergence. Germplasm accessions namely, karthigai samba, Kodai samba, Kapula sanna BH, Yah-Zamit B 56, Vialinica Gust, Kamee No (Japan) and Tepi Dumai may be used as parents to produce highly heterotic and superior transgressive segregants upon hybridization and its conservation may be helpful for the plant breeders to design future breeding programme.

Key words: Rice (Oryza sativa L.), germplasm diversity, phenotypic characterization.