Evaluation of genetic diversity on some rice lines and varieties

In order to study the genetic diversity of quantitative and qualitative traits of 125 rice genotypes, an experiment was conducted in rice research institute of IRAN in 2003. The experimental design was augmented in randomized complete block design with five checks and four replications. In this study 16 traits were measured on 10 random plants per each plot. Analysis of variance showed a highly significant difference among genotypes for all traits, except for milling recovery. That proved the existence of genetic variation among genotypes. The difference between blocks was not significant. Therefore the data of the unreplicated varieties were not adjusted and the average data of genotypes were analyzed. Results of phenotypic correlation indicated that number of tiller per plant, number of fills grain per panicle, panicle weight, grain length, grain shape, amylose content and gelatinization temperature had positive correlation while the rest of the totals had a negative correlation with grain yield. Stepwise regression analysis showed that 81.9 % of total variation in grain yield could be attributed to the number of tiller per plant, plant height, number of fills grain per panicle, 100- grain weight and grain shape. The results of path analysis indicated that the number of tiller per plant was the most important components of grain yield and had a high direct effect on it. Factor analysis resulted in five factors, which determined 66.8% of yield variation. The factors from 1 to 5 nominated as. Yield and yield component, grain appearance, morphological traits, grain milling and grain cooking quality factors respectively. Cluster analysis with complete linkage method classified all of the genotypes into six clusters. Genotypes of the first and second clusters had high yield and yield component, intermediate amylose and lower plant height. Therefore the crosses between genotypes of these two clusters and the genotypes of fourth and sixth clusters with 51 traditional varieties as low yielding but excellent grain quality are suggested to improve the high yielding and good grain quality rice varieties.