Over past years, grapevine adaptability has become of primary concern due to sharp cold-stressing weather of the unstable climates of Southern Russia accompanied by increasing mean annual temperatures, including higher degrees during plant winter dormancy. This situation causes considerable injury to the generative and vegetative organs in bush vine. Physiological and biochemical studies of the vine plant are of great importance for breeding cold-hardy grape genotypes. The article presents research related to studying cold hardiness in different grape varieties by content dynamics of starch, soluble sugars, abscisic acid and potassium ions in plant bark and buds. We studied grape varieties (interspecies hybrids) of the European-American (Dostoinyi, Krasnostop, Vostorg), West-European (Aligote), East-European (Zarif) and European-Amur-American origins (Kristall). The work aimed to analyse the physiological and biochemical properties of various ecological and geographical-origin grapes in winter time in order to identify the cold-hardiest genotypes. The Krasnostop and Vostorg varieties were ascertained as cold-hardy. Physiological and biochemical assays revealed an important contribution of water-soluble sugar-producing starch hydrolysis to low-temperature adaptation in Krasnostop and Vostorg, with the sugar content increasing 2.7-2.9 times. Krasnostop and Zarif were found to elevate the sucrose osmoprotectant winter level 4.7 and 6.6 times, respectively. All grape varieties decreased the abscisic acid content due to protective functions. Aligote was identified susceptible basing on a 2.3-fold potassium ion increase in frozen bark cell extract. The research conducted establishes the diagnostic value of the abovementioned physiological and biochemical parameters for cold hardiness evaluation in grape varieties.
