Comparison of Mid-Winter Cold Hardiness in the Bud and Cane Tissues of 24 Grape Cultivars Based on Low-Temperature Exotherm and Electrolyte Leakage Analyses

Mid-winter low temperatures increase the susceptibility to cold injury and thus limit the geo graphical distribution of some grape cultivars. In this study, mid-winter cold hardiness levels in the bud and cane tissues of 24 grape cultivars were estimated by means of a low-temperature exotherm (LTE) analysis and an electrolyte leakage (EL) analysis, respectively. Based on the cold hardiness estimates, the 24 cultivars were classified into five groups: very cold-sensitive, cold sensitive, moderately cold-hardy, cold-hardy, and very cold-hardy. Generally, Vitis interspecific hybrid cultivars could withstand cold better than V. vinifera cultivars in both tissues. According to the LTEs of the bud tissues, V. vinifera ‘Autumn Black’, ‘Hongju Seedless’, and ‘Cabernet Sauvignon’ were very cold-sensitive, while the interspecific hybrid ‘Cheongsoo’, ‘Muscat Bailey A’, ‘Shiny Star’, and V. vinifera ‘Greaca’ were very cold-hardy. According to the median lethal temperature (LT50) values of cane tissues determined by the EL analysis, V. vinifera ‘Emerald Seedless’, ‘IFG6’, ‘Autumn Black’, and the interspecific hybrid ‘Shooting Star’ were very cold-sensitive, while the interspecific hybrid ‘Ageude’, ‘Shine Muscat’, ‘Beta’, and ‘Campbell Early’ were very cold-hardy. However, some grape cultivars exhibited different cold hardiness levels by tissue type regardless of their parentage. The bud and cane tissues of V. vinifera ‘Greaca’ and ‘Cabernet Sauvignon’, respec tively, were relatively cold-hardy. Based on the combined cold hardiness estimates of both tissues, ‘Autumn Black’ could be classified as very cold-sensitive, while ‘Shiny Star’ and ‘Cheongsoo’ were relatively more able to withstand cold compared to the other cultivars. These results will help establish cultural and breeding strategies to overcome freezing stress on grapevines. KCI Citation Count: 0