Preliminary Evaluation of Salinity Stress Tolerance in Some Grapevine Native Cultivars and Hybrid Rootstocks under in Vitro Conditions

Considering the extent of grapevine cultivation in arid and semi-arid areas of the world where salinity stress is one of the important environmental stresses that limits grape production in Iran. Therefore, this research was carried out for preliminary evaluation and comparison of the reaction of three grapevine native cutivars; Bidaneh Sefid, Bidaneh Ghermez, Shahroudi and three hybrids H4, H6 and Kober5BB rootstocks in response to salinity stress in Temperate Fruits Research Center, Horticultural Sciences Research Institute, in Karaj, Iran, in 2015 -2017. The experiments were conducted as factorial arrangements in completely randomized design with five replications under in vitro conditions. The effect of salt was evaluated to identify the most tolerant cultivar/rootstock at four concentration levels of sodium chloride (NaCl); 0 (control), 25, 50 and 75 mM. The results showed significant effect of different salt levels on grapevine cultivars/rootstocks for all vegetative traits including; length of shootlets, number of leaves shootlet-1 and leaf expansion. Most of these traits increased at mild salt stress up to 25 mM. However, at 50 and 75 mM, which are decisive concentrations for tolerance of plant tissues to salinity, the traits showed significant decreases. According to the vegetative growth charcteristics, H6 hybrid rootstock and cv. Shahroudi had relative tolerance to the salinity stress that was confirmed by high preservation of their chlorophyll content, as observed about 2 mg g-1 FW in H6 hybrid rootstock. The total protein and proline contents of leaves showed that the total protein content in all grapevine cultivars and rootstocks followed increasing trend with stress intensity. The proline content had an appropriate association with the higher tolerance level of H6 hybrid rootstock and cv. Shahroudi to 75 mM of sodium chloride.