Genetic Analysis for take-all (Gaeumannomyces graminis var. tritici) disease resistance in bread wheat (Triticum aestivum L.) using diallel cross.

To achieving favorable outcomes in breeding programs, parental selection based on General combining ability (GCA) and Specific combining ability (SCA) is important. In order to investigate the genetically characteristics and general combining ability and specific combining ability and disease-resistant genes action against take-all in bread wheat, 6 wheat genotypes (729, 1622, 2109, 1528, 1546, 1526) were crossed in One-way diallelcross. Seeds of crosses (F1s) and parents were planted in the research greenhouse of Vali-e-Asr University of Rafsanjan. the take-all disease tolerance, stem dry weight, root dry weight, tiller number and Mn, Zn, k and Fe concentrations Were measured. Griffing analysis showed that general combining and specific combining ability were significant for all traits except for tiller number and iron element. The best general combiner in viewpoint of take-all resistance were 1622 and 729. The best hybrids in viewpoint of disease resistant were 2109×1546, 546×1528 and 1622×1526 that has the highest specific combining ability. Evaluation of genetic parameters by Hayman method for disease index and disease score confirmed the results of griffing analysis and showed that the dominance and over dominance of gene’s actions have the greatest importance in genetic control of the resistance to take-all disease (T-41 isolation). Finally, due to low specific heritability and low genetic ratio in resistance to take-all disease, it can be said that this trait do not respond well in early generations so selection after purity can be effective and can be done by bulk, single-seed descent and double haploid methods in wheat breeding.