Genetic study of wheat yield and its related traits using Diallel analysis in drought stress condition

Increasing the grain yield is the most important goal for breeders. Since grain yield has a polygenic heritability, it's difficult to study and so often breeders use the yield components to improve it. In order to investigating the genetic analysis of yield and it’s related traits in wheat, a 7×7 one-way diallel design was carried out in drought stress condition at research field of the University of Birjand, Iran, in 2015-2016. The genotypes included seven parents (Alvand, Anfaram9, Chamran2, Back Cross-Roshan, Ghods, Ofogh and local variety Sorkh-Dane) and 21 hybrids. Analysis of variance showed that there was a significant difference between genotypes in all studied traits. Griffing;s diallel analysis showed that general combining ability (GCA) and specific combining ability(SCA) of the parents for all studied traits except for harvest index were significant. The analysis of variance by Hayman’s method showed that the component a (additive variance), component b (dominance variance), component b2 (unequal frequency of dominant and recessive alleles) and component b3 (specific combining ability) were significant for most of the traits. Also,the component b1 (heterosis) was significant in all traits, except for harvest index, peduncle length, biological yield, stem weight and spike weight. The results of this research showed thatthe local varieties Sorkh-Dane and Alvand were the best and Anfrarm9 and Ofogh were the worst varietiesfor general combing ability. Also,the hybrids Ghods×Sorkh-Daneand Anfarm9× Alvandwere the best and Ofogh ×Sorkh-Daneand Chamran2 ×Sorkh-Danewere the worst hybrids for specific combining ability in Birjand weather conditions.