Adaptive stability of the apple tree in the conditions of a changing climate
In recent years, obtaining stable high yields of apple trees is limited by the impact of unfavorable factors of the winter period, including those resulting from local climate change. The purpose of this work is to evaluate the adaptation stability of the apple tree to winter stress on physiological and biochemical parameters, allocate the most stable varieties for the cultivation in the conditions of the Krasnodar region. Objects of research were the varieties of apple trees of various ecologic-geographical origin: Orfey, Idadred, Ligol, Prikubanskoye. Comparative studies of these varieties in the parameters of the water regime, the content of water-soluble sugars, soluble proteins, anthocyanins during the winter periods of 2020-2022 were carried out. It was revealed that the studied varieties of an apple tree in the conditions of an unstable climate of the South of Russia implement a similar mechanism for the formation of winter hardiness, which has quantitative differences in the content of some metabolites in the pre-winter and winter periods. It has been established that the cryoprotective function of water-soluble sugars has manifested as much as possible in the varieties Orfey and Ligol, their content increased by 2.57 and 2.69 times, respectively. Soluble proteins have made the greatest contribution to the formation of a protective response in varieties Orfey and Prikubanskoye in January, their content increased by 1.78 and 1.92 times, respectively, compared to December. The protective function of the anthocyanians was maximally manifested in December in the Orfey variety, in the bark of which there was an increase in their content by 5.23 times. The physiological and biochemical adaptation of the apple trees to the low temperatures of the winter period is achieved by increasing the fraction of the bound water in the total water content, increase the content of water-soluble sugars, proteins and anthocyanins in the bark and buds. According to the obtained data, the apple tree varieties Orfey and Prikubanskoe proved to be more adaptive in comparison with other studied varieties in the conditions of the pre-winter and winter periods and are recommended for cultivation in the Krasnodar region.