REACTION OF CENTENNIAL SEEDLESS VARIETY TO THE BUSH LOAD WITH SHOOTS AND BUNCHES IN THE CONDITIONS OF THE CENTRAL AGROECOLOGICAL ZONE OF VITICULTURE ACCORDING TO PHYSIOLOGICAL CRITERIA

The article considers the issue of the influence of the different loads of bushes with shoots and bunches on the physiological state of the leaves of Centennial Seedless grape variety in the agroecological conditions of the Central viticul-ture zone of the Krasnodar region. The Centen-nial Seedless variety is cultivated in a covering and grafted culture on a SO4 rootstock, drip irrigation. Climate is moderately continental, the soils are low-humus, leached powerful cherno-zems. The assessment of the physiological state of Centennial Seedless grape plants was carried out according to the variants of differentiated load by shoots and bunches (high, medium and low) according to the following parameters: quantum yield of photosynthesis, chlorophyll a and b content, carotenoids, relative water con-tent in leaves, water content in leaves and elec-trolyte leakage. In the studied summer months, the average air temperature was +24.3 °C, which is 0.4 °C above the climatic norm, the maximum temperatures rose to +35 °C. The total precipita-tion was 132 mm higher than normal due to heavy rains in some decades. The physiological and biochemical parameters of the leaves of the Centennial Seedless grape variety during the summer period were within the normal range – the quantum yield was above 0.7, the relative water content in the leaves was above 85 %, the water content was above 70 % except in Au-gust, the amount of chlorophylls a and b was above 1 except for the variant with the average load in July, the electrolyte leakage varied from 7.3 % to 17.3 %. In August, during the period of the greatest temperature stress for the leaves, the variant with a high load of bushes with shoots and bunches proved to be the best.