Combining Ability and Gene Action of Half Diallel Crosses in Bread Wheat (Triticum aestivum L.)

Abstract

Seven genotypes of bread wheat (Triticum aestivum L.) were used (SK 95, Side14, Side 12, SK94, Giemiza 9, Giemiza 7, Al-Fayyad) and their 21 crosses from half diallel cross, and they were planted at the Agricultural Research and Experiment Station of the Faculty of Agriculture. Agriculture - University of Kirkuk, using a randomized complete block design with three replicates in order to study the combining ability and the components of phenotypic variation and genetic parameters for the components of grain yield, parents and their crosses differed significantly in all traits, and parent 2 excelled in performance and effect of the general combining ability in the desired direction. The cross 2×6 showed significant superiority in the average of the studied traits, and the effect of the special combing ability, indicating that the heterosis breeding method can be adopted, and selection in the later generations, while crosses 2×4 and 2×7 excelled in grain yield and some of its components, and the effect of the special combining ability was not significant, which can be selected for in the early generations. The dominance variance showed higher than the additive variance, which was reflected in the decrease in the values of heritability narrow sense, and the degree of dominance was higher than one, so the over dominance is that controls the trait.