Selection of Clones Resistant to Cold in Seedless Grape Cultivars of Iran

Considering the rich diversity of grape germplasm of Iran, the severe cold winter occurred in 2007, provided a chance to evaluate responses of selected superior clones of Iranian seedless grape ciltivars to cold in natural and artificial (in freezer) conditions. Four one-year old branches per plant in each clone were selected and number of healthy and damaged sprouts were counted. Based on cold injury percentage, clones were classified into five groups, highly tolerant, tolerant semi tolerant, sensitive and highly sensitive. To assess the freezing temperature range, clones were maintained in freezer in temperatures
-12, -15, -18 and -21ºC for 24 and 48 hours. Using correlation coefficients (r pearson), bilateral relationship between cold affected traits was assessed. The global results showed that clone no. 18 of Bidaneh Ghermez cultivar was highly tolerant, clones no. 6 of Asgari and no. 14 of Bidaneh Ghermezi were tolerant, clone no. 14 of Bidaneh Sefid was semi tolerant and clone no. 3 of Yaghoti cultivar was sensitive to cold. Although the cold temperature tolerance range for grape cultivars is normally between -15 to -17ºC, in this study some selected superior clones could tolerate up to -21ºC temperature.