The ongoing increase in salinity is a major threat to olive cultivation in the world. This study aims to screen growth and physiological changes in five superior olive cultivars (‘Zard’, ‘Meshkat’, ‘Zagros’, ‘Sevillana’ and ‘Direh’) and one olive genotype (‘Dehsefid’) subjected to salinity stress in order to identify the most salt-tolerant cultivar. To achieve this, young olive seedlings were transplanted to plastic pots in the open field and were exposed to four levels of salinity (distilled water as a control, 6, 12 and 18 ds.m−1 NaCl as slight, moderate and severe stress, respectively). The obtained results revealed that growth attributes, relative water content (RWC) and chlorophyll (Chl) reduced salinity-severity behavior and reached minimum contents in severe stress, while malondialdehyde (MDA) and electrolyte leakage (EL) displayed counterintuitive results. ‘Dehsefid’ unquestionably outperformed due to the highest growth attributes, RWC and Chl. In contrast, ‘Direh’ was the most salinity-sensitive olive cultivar in this experiment. This result was attributable to the lowest growth parameters and the highest EL. These results recommend that ‘Dehsefid’ as the most salt-tolerant olive genotype could be a promising genotype to mitigate the detrimental effects of salinity on olive seedlings.
