GENETIC DIVERGENCE ANALYSIS FOR CERTAIN YIELD AND QUALITY TRAITS IN RICE (ORYZA SATIVA L.) GROWN IN IRRIGATED SALINE LOW LAND OF ANNAMALAINAGAR, SOUTH INDIA

Abstract

Genetic diversity among twenty six genotypes of rice genotypes from four states of South Eastern Region of India was evaluated using Mahalanobis D2 statistic. The experimental materials were evaluated during Samba season (August- December) 2005 and 2006 at the Plant Breeding Farm (11o 24’ N latitude and 79o 44’ E longitude, + 5.79 m MSL), Annamalai University, Annamalainagar, Tamilnadu, South India. Based on 12 morphological and quality characters namely, days to first flower, productive tillers per plant, panicle length (cm), number of grains per panicle, 1000 grain weight (g), grain length (mm), grain breadth (mm), grain L/B ratio, kernel length (mm), kernel breadth (mm), kernel L/B ratio and grain yield per plant (g) these genotypes were grouped into 13 clusters. Cluster I with seven genotypes was the largest cluster followed by Cluster V with four genotypes. Clusters IV, VII, VIII, X, XI, XII and XIII were mono genotypic clusters. Genotypes from more than one place of origin were grouped in one cluster, and genotypes from one state were grouped in more than one cluster. Geographical origin was not found to be a good parameter of genetic divergence. Clusters VI, III, and XII exhibited high values for most of the characters. The intra cluster distance was maximum (D = 100.90) in cluster I. The maximum inter cluster distance (D2 = 8235.56) was recorded between clusters II and III. Cluster XII recorded highest mean value for grain yield per plant and lowest mean value for days to first flower. Number of grains per panicle (42.71%) followed by days to first flower (25.62%) contributed maximum to total divergence. Hybridization among genotypes AUR 4, Annamalai mutant ponmani, Karnool sona, Jeeraga samba, AUR 7 and PY 5 from clusters III, II, XII and IX which had maximum inter-cluster distances and desirable values for days to first flower, number of grains per panicle, kernel length, kernel breadth, 1000 grain weight and grain yield per plant is likely to produce heterotic combinations and wide variability is segregating generations.