Selecting High Zinc-efficient and Assessment of Zinc Stress Tolerance of the Wheat Durum Genotypes

At percent, Zn stress tolerance using novel genetic resources is an important mitigation strategy for plant breeding. In this study, thirty-five durum wheat genotypes with different growth habits were evaluated under normal (non-stress) and Zn deficient stress during the 2014-15 cropping season. A total of ten Zn stress tolerance indices including stress tolerance index (STI), relative zinc-deficient index (RDI), yield index (YI), yield stability index (YSI), zinc-deficient resistance index (DI), abiotic tolerance index (ATI), stress susceptibility percentage index (SSPI), sensitive zinc-deficient index (SDI), and modified stress tolerance index (MSTI; K1STI and K2STI) were estimated. Results showed the significant influences of Zn stress on grain yield, as well as significant differences among genotypes for grain yield and the indices. The genotype G33 produced the highest grain yield under normal conditions by 0.854 g plant-1 while genotype G32 had the highest yield by 0.686 g plant-1 under Zn stress conditions. The genotypes G6, G13, G23, and G32 had less grain yield fluctuation, and G1, G21, and G29 genotypes had high grain yield fluctuation in two conditions. Cluster analysis showed that the genotypes, based on indices tended to four groups: tolerant, semi-tolerant, semi-sensitive, and sensitive genotypes, including 10, 17, 7, and 1 wheat genotypes, respectively. Grain yield was strongly positively correlated with STI, YI, DI, K1STI, and K2STI under two conditions, while negatively correlated grain yield with SSPI and SDI in Zn deficit stress condition, respectively. Using STI, YI, DI, K1STI, and K2STI, the genotypes G32, G33, and G19 were found to be the best genotypes with relatively high yield and suitable for both normal and Zn deficits stressed conditions. Therefore, they may be recommended to cultivate in Zn deficit prone regions of the world and also can be used in wheat breeding programs aimed at improving Zn stress tolerance.