Estimation of Genetic Structure of Yield and Yield Components in Bread Wheat (Triticum Aestivum L.) using Diallele Method

In order to estimate gene action of yield and yield components characteristics such as Spikelet Number per Spike, Biomass Weight, Kernel Number per Spike, Seed weight of 10 spikes, Hectoliter Weight, 1000 kernel weight and Yield, six genotypes of bread wheat such as: Arvand, Atrak, Zarrin, Karaj-3, Mv-17 and Navid were used in a 6×6 half-diallel cross. The crosses among the parents were down in 2009-2010. The experiment was conducted in a randomized complete block design with three replications at the research station Mahidasht Kermanshah, Iran in 2010-2011. Data were analyzed using diallel method. Analysis of variance showed significant differences (P<0.01) among the genotypes for all studied traits. Regression coefficient and epistasis tests showed fitness of additive-dominance model for most of the traits except grain yield, 10 spikes weight and seed weight in 10 spikes. Results of Hayman analysis showed that contributions of additive and non-additive effects were involved in control of the traits. Hayman’s graphical analysis showed that A and B parameters were significant at 1% levels. The highest and the lowest heritability of traits belonged to hectoliter weight and 1000 grains weight, were 57% and 13%, respectively. Regarding presence of additive effects for understudy materials and cumulative effect of genes help early generations, screening of cultivars and it, in turn may improve yield and its components.