The Comparison of NaCl Salinity Tolerance of Three Different olive Cultivars Based on Growth Characteristics and Leaf Sodium and Potassium Concentration

Salt stress could be the main limiting factor for developing olive culture in the most parts of Iran. Selection of tolerant cultivars could be the main strategy for growing olive in regions with saline soil and water. In this study, salt tolerance of the main Iranian olive (Olea europaea L.) cultivar, ‘Zard’ was compared with ‘Koroneiki I18’ and ‘Arbequina I38’cultivars which are growing in a greenhouse with a nutrient solution pot experiment. Two-year-old plants were transplanted to sand–perlite (1:1) culture, and were irrigated with half-strength Hoagland nutrient solution containing NaCl at various levels (0.5, 50, 100 and 150 mM(. Salinity decreased significantly growth parameters and the maximum suppressing effect was found at 150 mM NaCl. Leaf drop was observed from 60 days after salt application mainly in ‘Zard’. In contrast, leaf thickness increased at high salt stress. However, no significant difference was found among cultivars. The highest leaf Na+ concentration and Na+/K+ was found in ‘Koroneiki I18’, but the highest K+ was found in ‘Zard’. The lower reduction in plant growth parameters (shoot elongation, trunk diameter, total plant dry weight, internodes length, and total leaf area), and the increase of leaf thickness during salt stress was found in ‘Koroneiki I18’. Therefore, tolerance to salinity stress was as follows: ‘Koroneiki I18’ ‘Arbequina I38’ ‘Zard’.