Relative Salt Tolerance of 22 Pomegranate (Punica granatum) Cultivars

A greenhouse experiment was conducted to determine the relative salt tolerance of pomegranate (Punica granatum) cultivars. Twenty-two pomegranate cultivars were irrigated weekly with a saline solution at an electrical conductivity (EC) of 10.0 dS.m(-1) for 4 weeks and subsequently with a saline solution at an EC of 15.0 dS.m(-1) for another 3 weeks (salt treatment). Another group of uniform plants was watered with a nutrient solution without additional salts at an EC of 1.2 dS.m(-1) (control). No visual foliar salt damage (leaf burn, necrosis, or discoloration) was observed during the entire experimental period; however, salt treatment impacted pomegranate growth negatively, with a large variation among cultivars. Salt treatment reduced shoot length by 25% and dry weight (DW) by 32% on average for all cultivars. Cluster analysis classified the 22 tested pomegranate cultivars in two groups. The group consisting of 'Arturo Ivey', 'DeAnda', 'Kazake', 'Russian 8', 'Apseronski', 'Purple Heart', 'Carolina Vernum', 'Chiva', 'Kunduzski', 'Larry Ceballos 1', 'ML', 'Salavatski', 'Spanish Sweet', and 'Wonderful' was more salt tolerant than the group including 'Al-Sirin-Nar', 'Kandahar', 'SurhAnor', 'Early Wonderful', 'Angel Red', 'Ben Ivey', 'Utah Sweet', and 'Mollar'. The sodium (Na) concentration in the leaf tissue of all 22 pomegranate cultivars was less than 1 mg.g(-1) on a DW basis. All pomegranate cultivars in the salt treatment had an average leaf chloride (Cl) content of 10.03 mg.g(-1) DW-an increase of 17% from the control. These results indicate that pomegranate plants have a strong capability to exclude Na and Cl accumulation in leaf tissue. In conclusion, the pomegranate plant is very tolerant to saline water irrigation up to an EC of 15 dS.m(-1) with little foliar salt damage and a slight growth reduction. Investigation is needed to determine the effects of saline water on the fruit yield and nutritional quality of pomegranate.