Fruit growing
and viticulture of South Russia

Annotation

This work presents the data on study results of two irrigation algorithms for Cabernet�Sauvignon grape variety in production conditions of the Livadia branch of FSUE PJSC Massandra in the South Coast of Crimea in 2019-2020. Experimental physiological algorithm provided for two water stresses to be carried out. The first short-term water stress was during the period of berry growth, t he second one � during the stage of berry ripening. The depth of water stress during the stage of berry growth in predawn values of water potentials in leaves was determined in the range of 0.5�0.55 MPa. The depth of water stress during the stage of berry ripening was in the range of �0.45��0.5 MPa. Crop load of plants in experimental version was determined as higher than normal � by 20 % compared to the optimal one. The control variant was a stress-free irrigation strategy against the background of optimal crop load. Basic tool to control water status of plants was a pressure chamber for measuring water potentials of leaves. Growing seasons of 2019-2020 were characterized by a significant rise of average monthly air temperatures compared to average long-term values and low annual precipitation amount: 357.0 and 410.6 mm, respectively. Such weather conditions have led to high evapotranspiration flow rate in grape plants. And yet, in the third decade of June, the plants of experimental variant experienced extreme water stress (�0.5��0.55 MPa). Ripening of grapes in stress variant of irrigation also took place with a moisture deficit. Average values of leave water potentials in predawn hours were �0.45-0.50 MPa. As a result of the research, it was found that stressful irrigation strategy against the background of an increased crop load, compared with a stress-free one and an optimal crop load, allowed an increase in the mass concentration of sugars by 1.5 g /cm3 , in the content of total phenolic substances by 28.3 % and coloring agents by 33.3 %.