Study of Combining Ability in Five Varieties of Rice (Oryza sativa L.) for Six Morphological Traits Using a Diallel Cross Mating Design

Six morphological traits of rice were evaluated in a 5 × 5 one-way diallel cross using a randomized complete block design corresponding with their F1 generations in 2007 at Iranian Rice Research Institute – Amol. Results from analysis of variance for traits of plant height, flag leaf angle, flag leaf length, flag leaf width, internode length and panicle length exhibited significant genetic differences among parental cultivars and their hybrids. Significant means of squares for GCA and SCA showed the positive actions of additive and non-additive effects on controlling these traits. Also, ratio of mean squares of GCA on SCA ( ) were significant in all traits that showing a higher importance for role of additive effects in comparison with role of non-additive effects in functions of genes controlling the studied traits. High narrow sense heritability of these traits proved majority roles for additive effects of genes in genetic control of the studied characteristics therefore, selection of these triats may be succeed. Overall, both of Neda and IR62871-175-1-10 were the best parents for general combining ability for reducting plant height, flag leaf length and internode length and increasing flag leaf width. Meanwhile, because of higher SCA, Neda × Binam and Neda × Dasht were the best hybrids for increasing spike length and decreasing height, respectively.