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چکیده
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Drought stress limits the growth and performance of plants. Considering the increasing drought stress worldwide, the selection of resistant cultivars is important. Grapes (Vitis vinifera L.) are drought-toler- ant and often cultivars unknown. The grape cultivars of Khuzestan, Iran, are among those that have not been extensively studied for their drought tolerance. Our initial studies have shown that some of these cultivars exhibit high drought tolerance indices, even compared to globally tolerant cultivars. In the present study, the effect of drought stress at four levels (20, 50, 75, and 100% of field capacity) was investigated on eight cultivars (native Khuzestan cultivars: ‘Bangi’, ‘Yershii’, ‘Soltani’, and non-native cultivars grown in Khuzestan: ‘Per- lette’, ‘Flame Seedless’, ‘Yaghouti Ghermez’, and ‘Yaghouti Sabz’, and ‘Asgari’). The experiment was con- ducted in a factorial design with three replications in a completely randomized design. The results showed that with increasing drought stress, a decrease in root and shoot growth was observed in all cultivars. Additionally, membrane stability index, relative water content, and protein content decreased. Conversely, Total soluble sol- ids, proline, glycine betaine, and malondialdehyde increased. This increase was observed in all cultivars, although the magnitude of increase varied among cultivars. The increase in antioxidant enzyme activities of cat- alase and peroxidase was also significant. Native cultivars, especially ‘Soltani’, ‘Yershii’, and ‘Bangi’, had less decrease in membrane stability index and relative water content compared to other cultivars. Additionally, these native cultivars showed a greater increase in Total soluble solids level and catalase and peroxidase activities com- pared to other cultivars. Overall, based on the conducted study and comparison with previous studies, it appears that ‘Soltani’, ‘Yershii’, and ‘Bangi’ cultivars have a high degree of drought tolerance
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