A hydroponic experiment was carried out to study physiological, and biochemical changes of Moroccan barley (Hordeum vulgare L.) varieties under salt stress conditions. Four barley varieties were grown under three stress levels, namely 0 mM, 200 mM NaCl, and 300 mM NaCl. The ANOVA for both sensitive and resistant varieties indicated that salt treatment was the main source of variability of all studied traits. Salt constraint reduced significantly root and shoot dry weight, relative water content (RWC) and chlorophyll content (Chl a, Chl b and Chl T). However, increases of electrolytes leakage (EL), proline and total soluble sugars contents (TSS) have been recorded. In addition, a large variability was found between varieties for all measured traits. ‘Massine’ and ‘Laanaceur’ varieties displayed higher values of RDW and SDW. When compared to controls, lower values of RWC, Chl contents were recorded in ‘Amira’ and ‘Adrar’ indicating their relative sensitivity to salt stress. Findings from the principal component analysis indicated that most of the variation was captured by the PC1 (72% of the total variance) which grouped samples into three categories according to salt treatment. Correlation studies highlighted significant associations between most parameters. Positive relationships were found between RDW, SDW, RWC, Chl content and soluble proteins contents, while all of these parameters were negatively linked to electrolytes leakage intensity, Proline and total soluble sugars contents. The results from this study showed that ‘Massine’ and ‘Laanaceur’ were relatively salt-tolerant. These two resistant varieties could represent a good backdrop for breeding for barley salt tolerance.

Keywords: Hordeum vulgare, barley, salt stress, Morocco, hydroponic culture