Evaluation of the genotypes and F1 generation of rice in hybridization block

In order to maintain of local and foreign rice genotypes and getting genetic diversity through hybridization and finally producing new rice varieties, an experiment was conducted with 107 genotypes in 2002.All genotypes were sowed in nursery at 3 date with 15 days interval for flowering synchronization. In addition, 46 F1 generations were sowed in nursery. All parents and F1 generation were planted as one seedling per hill in the paddy field. The row number of parent, and F1 generation were 3 and 1, respectively. The seedling space was 25cm ×25cm. Sixty-nine crosses were done between local and foreign parents and the result was showed that enough seeds were obtained for each f1 hybrid. The grain yield of each parent was harvested individually because of maintaining of purity. The grain yield of each F1 was harvested as bulk after removing of the off types. In this study 9 traits including number of tiller per plant, number of filled grain per panicle, 100-grain weight, plant height, panicle length, leaf length, leaf width, day’s to 50% of flowering and grain yield were measured on 5 random plants from each plot. Further the results showed that the grain yield had a positive and significant correlation with number of tiller per plant, number of filled grain per panicle, 100- grain weight, leaf width and days to 50% of flowering. It had also a negative and significant correlation with plant height, panicle length and leaf length. Stepwise regression analysis showed that the maximum variation in grain yield could be attributed to the number of filled grain per panicle, plant height, number of tiller per plant and 100-grain weight. The results of path analysis indicated that the number of filled grain per panicle were the most important components of grain yield and had a high direct effect on it. Therefore this trait could be used as a good selective index to select high yielding varieties