Agrophysiological Responses of Barley Cultivars to Salt Stress and Zinc Fertilization

Abstract  In order to study the effects of agrophysiological responses of barley genotypes to salt stress and zinc fertilization, a field experiment was conducted in a strip-split-plot design with three replications. Saline irrigation water in three levels [۲ (low), ۱۰ (moderate) and ۱۸ (high) dS m-۱] were applied as vertical factors. Three barley genotypes [‘Morocco’ (salt-sensitive), ‘Nosrat’ (semi salt-tolerant) and ‘Khatam’ (salt-tolerant)] were arranged within the vertical factors. The horizontal factors were four zinc fertilizer applications [Nano-ZnO, Zn-EDTA, simultaneous applications of Nano-ZnO + Zn-EDTA, and water (control)]. With increasing  salinity, maximal efficiency of PSII (Fv/Fm), chlorophyll content (SPAD), relative water content (RWC), K+ ion, K+:Na+ ratio, number of spike (NS), kernel number per spike (KNS), thousand-kernel weight (TKW), and grain yield (GY) decreased, but electrolyte leakage (EL) and Na+ ion concentration increased. The tolerant genotype (Khatam) had maximum Fv/Fm, SPAD, RWC, K+ ion, K+:Na+ ratio, KNS and GY. Minus zinc application (check) had minimum Fv/Fm, SPAD, K+:Na+  ratio and GY. Nano-ZnO had the highest EL and the lowest KNS, K+ and Na+ ions. Zn-EDTA application provided the highest RWC, K+ ion, K+:Na+ ratio, KNS and GY. Overall, it was concluded that Zn-EDTA can be as a proper toolfor increasing barely yield under salinity stress conditions.  KeyWords: Barley, Salinity stress, Yield, Zinc applications.