Genetic development of improved genotypes with good floral charactaristics is the an important approach in the production of hybrid rice seed. Ten rice parental lines where four of them have cytoplasmic male sterility while the other six use restorer. These ling were crossed to obtain 24 hybrid combinations, through a factorial mating design. The parental lines and their 24 F 1 hybrids were grown in randomized complete blocks design with three replications at Rice Research and Training Center Farm, Sakha Kafr El-Sheikh, Egypt during the two seasons of 2011 and 2012. Data were recorded on six floral traits viz., anther length, anther breadth, number of pollen grains anther -1 , stigma length, stigma breadth and glume opening angle. The analysis of variance of all genotypes revealed highly significant mean squares for all studied traits, suggesting the presence of genetic differences among the genotypes used in this study. The magnitude of genetic parameters indicated that the additive variance (σ 2 A) for anther length, number of pollen grains anther -1 , glume opening angle traits were higher than the corresponding nonadditive variance including dominant (σ 2 D). These results indicated that these traits were largely governed by additive gene action. Thus, the estimated values of heritability in broad sense were higher than heritability in narrow sense for all the studied floral traits. A major part of the total phenotypic variance was due to non-additive including dominance genetic variances for all floral traits. The maternal effects were affective in stigma breadth (37.25%) and glume opening angle (70.15%). The contribution of maternal and paternal interactions (Line x Tester) were found to be vital for anther breadth (57.86%) and stigma breadth (37.43%). The ten parental lines were distinctly classified into two major clusters (below 1200 Euclidean distance) according to the similarity diagram.

Fifteen hybrids were produced from a partial diallel crosses mating design among six lines. They were studied along with their parents for combining ability and genetic variations for yield and its component characters. Both GCA and SCA variances were found to be highly significant for all the characters indicating the importance of both additive and non-additive gene action. However, preponderance of non-additive (dominance) gene action was recorded for grain yield plant -1 , panicles plant -1 , filled grains panicle -1 and spikelets fertility % while 1000-grain weight was controlled by additive type.The restorer rice genotype , PR78, PR2 and Giza 178R were found to be good combiners for grain yield plant -1 and most of yield component characters. The crosses involving the above parents were promising because they showed high SCA effects.