Biplot and heterosis analysis for diallel crosses of bread wheat (Triticum aestivum L.) under normal and salt-stressed environments

Salinity is one of the abiotic stresses and exploitation of heterosis could increase the crop yield and extend the stress tolerance, especially in salinity stress. In this research, a set of full diallel design involving 7×7 crosses from cultivars including Flat, Bam, Ghods, Roshan, Arg, Kavir and Pishtaz were conducted in a randomized complete block design with three replications under both normal and salt stress conditions in Yazd, Iran. The results of heterosis and graphical analyses using GGE biplot approach indicated high narrow and broad sense heritabilites and heterosis of crosses for yield and biomass traits, especially in saline condition. Graphical biplot determined two different heterotic groups for yield and biomass characteristics in saline condition. The ranges of heterosis for yield trait were between -18.5 to 24.1% in normal condition and -21.3 to 60.1% in saline condition, respectively. Also, the ranges of heterosis for biomass were between -22.2 to 16.1 % in normal condition and -19.7 to 55.3 % in saline condition, respectively. The results of this research showed that under saline conditions there were significant crosses for negative and positive heterosis for studied trait. High heterosis and great narrow and broad sense heritabilites for yield and biomass traits indicated that finding a better line along with a fixed relative heterosis is possible using selection methods from the progenies in saline condition.