Study of genetic control of salinity tolerance in bread wheat cv. Kavir-using generation mean analysis

Kavir wheat is one of the salinity tolerant cultivars that have been improved in Iran. In this research, F۱, BC۱, BC۲ and F۲ generations derived from a cross between Kavir × Arta and Kavir × Moghan۳ (Arta and Moghan۳ are susceptible to salinity) were evaluated through generation mean analysis in non-stress and salinity stress conditions in a randomized complete block design with three replications at the Agriculture Research Center of Kerman. The irrigation water salinity was ۰.۶۳ and ۱۵ dS/m in non-stress and stress conditions, respectively. The salinity of farm soil was ۲.۱ dS/m in both conditions. The traits of flowering and maturity time, plant height, flag leaf relative water content, amount of Na+ and K+ in flag leaf, yield per plant and hundred seed weight were recorded for each treatment during the growth season and after harvest. The frequency distribution showed that Kavir was the superior parent in terms of the amount of Na+ while Arta and Moghan۳ were the superior parent in terms of the amount of K+ and K+/Na+ in non-stress conditions. The concentration of Na+ decreased and the concentration of K+ and K+/Na+ increased in Kavir in stress conditions, while this condition was contrary in Arta and Moghan۳. These results showed that when the plant encounters stress, some genes will be activated, which will result in a decrease in the concentration of Na+ and increase K+ uptake. Scale test results rejected the adequacy of the additive-dominance model and confirmed the presence of epistatic effects for these traits (except for K+/Na+ in stress conditions) in both environments. None of these tests were significant for the K+/Na+ in stress conditions. This result showed that the K+/Na+ was affected by additive × additive gene effect and the adequacy of the three-parametric models in the joint scaling test also confirmed this.