Response of some vegetative and physiological traits of Iranian and foreign grape cultivars to drought stress

Drought stress, as the most important environmental stress, severely disrupts plant growth and limits production and yield more than any other environmental factor. Investigation of the role of drought stress conditions on plant morphological, physiological and photosynthesis characteristics may provide a tool to understand the basic drought resistance. To investigate the drought tolerance of Iranian and foreign grapevines (Vitis vinifera L.) cultivars, A pot experiment was conducted with 5 replications, and 20 Iranian and foreign rooted grape cultivars exposure with two treatments of 90 (control) and 50 (drought stress) water requirement. Iranian grape cultivars included Rashe, Bidane Sefid, Bidane Ghermez, Yaghoti, Fakhri, Khalili Sefid, Ghezel Ouzom, Asgari, Gazandai, Gachi Amjagi, Tabraze Ghermez, Tabraze Sefid, Laal, Hosseini and Shirazi and foreign cultivars including Black Seedless, Flame Seedless, Perlette, Ruby Seedless and Torkaman 4. Based on results, after three months of drought stress, the interaction of drought stress and cultivar was significant for leaf number, leaf area, current branch length, internode length, root length, root volume, root fresh weight and electrolyte leakage and not significant for stem diameter, root dry weight and relative water content. In general, despite the increase in chlorophyll a, b, total and carotenoids in some cultivars, these physiological characteristics decreased by 29.43, 20.47, 27.47 and 22.15%, respectively under drought stress. Photosynthetic traits such as photosynthesis, transpiration, stomatal conductance and intercellular CO2 concentration were also significantly affected by drought stress and reduced by 39.11, 42.36, 54.98 and 30.33% in drought conditions. Rashe, Khalili Sefid, Yaghoti and Laal cultivars showed good resistance to drought stress conditions, whereas Fakhri, Shirazi, Bidane Sefid, Gazandai and Gachi Amjagi cultivars were sensitive to drought stress.