Salt-tolerant barley ideotypes for hot arid zones: Genotypic versus salinity effects on yield, grain quality and physiological traits

Barley (Hordeum vulgare L.) is a key cereal crop in arid regions, where it is frequently grown under saline irrigation. This study investigated the effects of irrigation salinity and genotype on agronomic performance and grain quality in ten Syrian barley genotypes grown in sandy soils under three salinity levels (2.6, 10, and 15 dS m⁻¹) over two seasons at the International Center for Biosaline Agriculture (Dubai, UAE). Increasing salinity markedly reduced yield and biomass, and to a lesser extent grain weight, plant height, crop duration and leaf chlorophyll content. Salinity elevated sodium (Na) levels in grain and vegetative tissues, while also increasing grain carbon isotope composition (δ¹³C) and slightly decreasing leaf chlorophyll content. These results indicate that the main effect of salinity was osmotic, rather than ionic, causing water stress. Genotype had a significant effect on nearly all traits evaluated and was a stronger source of variation than salinity for grain mineral concentrations. Notably, grain Na concentration was more strongly influenced by genotype than by salinity, and was positively correlated with yield across genotypes, while higher-yielding genotypes also tended to exhibit lower grain δ¹ ³C, suggesting a more favorable water status. Lower-yielding genotypes tended to accumulate higher concentrations of N and minerals in the grain, indicating a potential trade-off between yield and nutritional composition. Overall, genotypic variation was the primary determinant of both yield and grain quality under saline irrigated conditions, highlighting the importance of genotype selection for productive and nutritionally adequate barley cultivation in arid environments.