Physio-biochemical responses and yield performance of North African barley genotypes submitted to moderate and severe salinity

Barley is the second most consumed and cultivated cereal in Morocco after wheat. This study aims to explore the effect of salt stress on nine barley genotypes of different North African origins. Plants were exposed to moderate (8 dS m-1) and high (12 dS m-1) salinity levels. At the reproductive stage, physiological, biochemical traits and yield components were measured. Our results revealed that genotypes substantially differed in their responses to moderate and severe salt stress conditions. The analysis of variance indicated highly significant effects of the salinity, origin, type, and their interactions. Interestingly, barley plants exposed to salt stress exhibited a high increase in shoot electrolyte leakage, Na+/K+ ratio, hydrogen peroxide, and Malondialdehyde contents. Moreover, salt-tolerant barley genotypes showed high osmo-protectant accumulation ability with increases in proline content, soluble sugars content, and proteins content under salinity compared to the control. A significant rise in antioxidant enzyme activities in shoots of all genotypes was recorded under both moderate and severe salinity levels, leading to varying growth responses among the genotypes subjected to salt stress. Furthermore, a stepwise regression revealed that under salinity stress conditions, hydrogen peroxide level was the most predominant trait and had the maximum effect on kernel weight and grain yield. As a consequence, the role of oxidative and osmotic homeostasis adjustment in preventing the formation of reactive oxygen species and in maintaining considerable yield rate sustain, water use efficiency, and uptake of essential ions balanced maintenance under salt stress is emphasized. This confers the ability to survive under stress conditions as a genetic source for developing salt-tolerant breeding programs.