Investigation of phenotypic and genetic diversity and evaluation of relationship among agronomic traits in cold tolerant lines of rice (Oryza Sativa)

To assess the phenotypic and genetic diversity and their relationships in five genotypes of rice cold tolerant (selected from the experiments of 20 cold tolerant lines) and a control, a three-year experiment was conducted as a randomized complete block design in Chaharmahal & Bakhtiari province. Results showed that the differences among genotypes was significant for days to heading and maturity, plant height, number of stems per plant, panicle length, number of grains per panicle, 100-seed weight and seed yield per unit area. In all traits, the phenotypic coefficients were more than the genetic coefficients. The number of days to maturity had maximum and seed weight had the lowest general heritability. The seed yield was relatively high heritability, too. Yield phenotypic and genetic correlations was positive and significant with number of fertile tillers per plant, number of filled grains per panicle and grain weight and was negative and significant with the other traits except panicle length. In stepwise regression analysis, fertile tiller number per plant, number of seeds per panicle, grain weight, and number of days to heading were entered into the model, respectively and were made a total yield of 91%. Path analysis revealed that number of fertile tillers per plant had the highest direct effect on grain yield. Seed weight also having a high positive effect and a positive indirect effect via number of tillers per plant, was highly significant positive correlation with yield, in spite of the negative indirect effects from other traits.