Evaluation of salinity tolerance of three olive (Olea europaea L.) cultivars

Tarom region of Zanjan province is one of the olive production centers in Iran, which faced a crisis of salinity stress following the salinization of water resources. The selection of salinity tolerant cultivars using pivotal characteristics is one of the interesting challenges. This study was conducted to investigate the behavior of 'Zard, 'Abou-satl', and Arbequina' cultivars in the context of using marginal waters. Therefore, one-year-old self-rooted plants of these cultivars were potted and irrigated with 2, 5, 8, and 12 dS/m saline water for three months in the greenhouse, and certain physiological and morphological features were studied. The results show that 'Zard' and Abou-Satl' cultivars tolerated salinity of 8 and 12 dS/m, maintained their photosynthesis in medium salinity (5 dS/m), and grew well in these conditions. In contrast, the 'Arbequina' cultivar exhibited extreme susceptibility to salinity. In the high salinities, there was a lower slope in the increase of Na+ concentration in the leaves of the 'Zard' cultivar. Also wet and dry biomass in this cultivar decreased much less than the others. A more severe reduction in the transpiration of the 'Zard' cultivar indicated better efficiency of water retention mechanisms and high water use efficiency. The photosynthesis rate of 'Zard' and Abou-Satl' cultivars were less affected under salinity stress. They reduced the accumulation of Na+ and increased the K+ concentration in leaves. These two cultivars had suitable responses to salinity and were recommended for planting in regions affected by salinity.