Seasonal changes of electrolyte leakage, carbohydrate contents and Re-growth in four cultivars of grape vine (Vitis vinifera l.) cuttings, under freezing stress

Grapes are one of the temperate fruit crops most frequently damaged by freezing temperatures. An investigation was carried out to evaluate the effect of freezing temperatures during the dormant season on four commercial grape cultivars. Factorial experiment was conducted using a completely randomized design with three assemblage dates (end of autumn, middle of winter and end of winter), temperature treatments (25, -10, -12, -14, -16, -18, -20 and -220C) and cultivars (Kolahdary, Red rasin, Yaghoti and White rasin) with three replications in Horticultural Sciences Laboratory of Ferdowsi University Mashhad in the year 2010. It was concluded that in -220C, electrolyte leakage of cultivar Kolahdary at the end of autumn and Yaghoti at the end of winter with 60 and 62 % showed highest the value, respectively. Cultivar Red rasin in the middle of winter with %39 had lowest value. Also, cultivar Kolahdary at the end of autumn and cultivar Yaghoti at the end of winter by 24.13 and 27 mg/l and cultivar Red rasin at the middle of winter by 37.33 mg/l had lowest and highest carbohydrate values respectively. The lowest and highest value of re-growth were gained in cultivar Yaghoti and Red raisin by 12 and 45 % respectively. Therefore, due to high carbohydrate content and low electrolyte, leakage Red raisin was selected as freezing tolerance cultivars.