The Comparison of Some Effective Physiological Characters to Improve Cold Tolerance of Seeded and Seedless Grapevine Cultivars During the Dormancy and Growing Seasons

The best way to increase the tolerance of plants against stresses is to know the specific characteristics of the cultivars, which is needed both for planting in different climatic conditions and for breeding programs of these cultivars. For this reason, the exact study of the physiological traits of native cultivars of each region in the various stages of growing of grape is necessary. Sampling was done in five times. During the dormancy season (Winter 2013) three times samplings of stems with buds were done and biochemical parameters of proline, electrolyte leakage and soluble sugar were measured. The aim of this study was to investigate some of the effective parameters of cold tolerance in five cultivars of grapevine including “Bidaneh Sefid”, “Bidaneh Ghermez”, “Lal”, “Sahebi” and “Fakhri” in a randomized complete block design (RBCD) with three replications. In the growing season (spring 2013) two times samplings were collected from the leaves of cultivars and biochemical parameters such as proline, malondialdehyde (MDA), soluble sugars, photosynthesis pigments, total protein, activity of antioxidant peroxidase, polyphenol oxidase and ascorbate peroxidase enzymes were measured. Result showed that there were significant differences between the cultivars in both winter and spring and in all considered characteristics. The winter cultivar of 'Fakhri' with minimal electrolyte leakage in all three times of sampling (33.12 µSiemens/gr Fw in January, 23.17 µSiemens/gr Fw in February and12.89 µSiemens/gr Fw in March) was more prepared to tolerate environmental stresses than other cultivars. In the spring, in both sampling times of spring season, cultivar of “Bidaneh Ghermez” with the least amount of malondialdehyde (3.7 µmol/gr FW in late April and 4 µmol/gr FW in early May) and the highest proline (10.27 µmol/gr FW late April and 7.39 µmol/gr FW in early May), and protein (respectively 0.26 mgr/gr FW late April and 0.23 mgr/gr FW in early May) were more prepared to tolerate environmental stresses than other cultivars that were examined in this study. The cultivar of “Lal” with the highest level of malondialdehyde (9.52 µmol/gr FW in late April and 4.52 µmol/gr FW in early May) showed lower relative stress endurance compared with other studied cultivars. In the winter, cultivar of 'Fakhri' had higher stress forbearance than other cultivars. Also, in the spring, cultivar of “Bidaneh Ghermez” had more and “Lal” had the lowest stress endurance than other cultivars that were examined in this study. Considering all the traits studied, it can be stated that in winter tolerance of seeded cultivars is more suitable than seedless cultivars. Seedless cultivars are more sensitive to temperature variations and generate severe reactions.