In order to determine the genetic variability and to classify of genotypes, 100 local as well as improved rice varieties were studied in a lOxlO simple lattice design in Rice Research Institute of Iran (Rasht). Such characters as grain yield, yield components and quality traits were evaluated. Analysis of variance demonstrated a significant difference among genotypes at 1% probability level for all traits. The highest and lowest of genotypic variability coefficient were observed for flag leaf surface and days to 50% flowering, respectively. The highest and lowest of broadsense heritabilities were obtained for days to 50% flowering and plant weight, respectively. Cluster analysis by use of Ward’s minimum variance classified the genotypes into seven groups. This grouping was confirmed by Pseudo Hoteling T2test and cubic clustering criterion. Most improved and imported varieties were groupef in one cluster while high cooking quality local varieties stood in another cluster.
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