Combining ability and gene action estimates for some yield attributes in durum wheat (Triticum turgidum L. var. durum)
Combining ability and gene action of a set of durum wheat characters were studied using 6 x 6 half diallel crosses. Results revealed that general (GCA) and specific (SCA) combining ability mean squares were significant for all studied traits, suggesting the importance of both additive and nonadditive components in the inheritance of these traits. Baker ratio indicated the predominance of additive gene effects for the majority of traits studied except grain yield. From the GCA effect, it was observed that none of the six parents was a good general combiner for all yield components. Among the fifteen crosses, Zenati-Bouteille/Flamengo x Gta/durum followed by Waha x Ofanto, Waha x Mexicali75 and Ofanto x Guemgoum Rkhem expressed the greatest positive SCA effect for grain yield. Days to heading and spikes number index could be used as an indirect selection criterion for better grain yield. Therefore, selecting early heading genotypes having high fertile tillers number could improve grain yield.
Keywords: durum wheat; diallel cross; GCA; SCA; yield