Estimation of Genetically Parameters and Combining Ability of yield and Yield Components in Bread Wheat by Diallel Method

In order to estimate genetical parameters, general and specific combining ability of bread wheat to determine proper parents for crossing and producing new cultivars, six promised lines planted in randomized complete block design with three replications, in 2017-18 cropping and varieties including, Falat, Mehergan, Ehsan, Sistan, Bam and N-80-19 were planted in Eraghi Mohalle (Gorgan) station in 2016-17 cropping season. A full diallel mating among six parents for generating F1 progenies were done. Sixparental genotypes and 30 F1 progenies were season. The results revealed that cultivar Ehsan was the best general combiner for hundred grain weight. Cultivar Ehsan and Line N-80-19 had the highest general combining ability for grain yield and biomass, respectively. Therefore, it is recommended that these genotypes can be applied in hybridization to increase grain yield and biomass. Additive variance of traits including plant height, peduncle length, grain weight in spike and hundred grain weight was more than dominance variance. Furthermore, Ehsan cultivar had the highest general combining ability (GCA) for grain yield and biomass and hybrids raised from 2×3 (Ehsan×Mehrgan) cross had the highest specific combining ability (SCA) for grain yield and biomass.