Evaluation of Morphological and Physiological Traits as Indicators of Drought Tolerance in Twelve Pomegranate Cultivars (Punica granatum L.)

Abstract: Pomegranate (Punica granatum L.) is one of the oldest edible fruits that have high nutritional value and medicinal properties. In this work, an investigation was designed as factorial in the framework of completely randomized design in order to evaluate physiological and morphological traits that can be used for screening the drought tolerance of pomegranate cultivars. Twelve pomegranate cultivars were tested. The obtained results indicated that increase of irrigation interval increased ion leakage, soluble sugar, and proline concentration and decreased growth parameters, photosynthetic pigments, leaf relative water content, and membrane stability. Under drought stress, pomegranate cultivars showed different responses in the measured parameters such that the highest leaf relative water content, leaf area, specific leaf weight, photosynthetic pigments and osmotic regulators were observed in Zard Nar-e-Faruq and Shirin Ghermez Zabol cultivars, which could be the reason for the greater tolerance of these cultivars to drought stress. Super Shirin and Bi Haste Zodras Shekari cultivars with the highest ion leakage and lowest leaf relative water content and membrane stability had the lowest tolerance to drought stress. Based on the obtained results, specific leaf area, leaf water content, membrane stability index, relative water loss and phenolic compounds presented the greatest changes under stress condition compared to control group which could be used to screen pomegranate genotypes for drought stress.