INFLUENCE OF GRAPE CULTURE AND AGROTECHNICAL METHODS ON ITS YIELD AND WINE QUALITY

Abstract

The quality characteristics of technical grapes and wines largely depend on the management system of this culture. The aim of the study was to establish the influence of various norms of the load of a grape bush in a self-rooted and grafted culture on the yield, quality of grapes, as well as the aesthetic and biological value of wine products in the conditions of this terroir. The experiment was carried out in 2018-2019 in Temryuk district of Krasnodar region. The objects of research were grapes and wine material of Krasnostop AZOS variety in a grafted and rooted culture with a different load of shoots on the bush. The plantation was established in 2007 according to 3 × 2 m scheme, the formation of the bush was a spiral cordon AZOS-1. The soil of the experimental site is soddy-calcareous, thick, low-humus, light-clayey granulometric composition, formed on tertiary saline clays. The upper horizon (0-60 cm) has favorable agrochemical properties and a sufficient level of fertility. The normalization of the load by shoots of grape bushes cultivated in a self-rooted or grafted culture had a significant impact on the yield and technological qualities of Krasnostop AZOS grape variety during the years of the study. The highest yield result was provided by the variant of own-rooted bushes Krasnostop AZOS with standardized shoots 36 ... 40 pcs/bush - 3.45 kg/bush. The excess yield was significant at the 5% significance level in comparison with the control and other variants of the experiment and amounted to 0.45-0.9 kg/bush. The best ratio of sugar content and titratable acidity (standard glucose value - 4.36) for dry red wines had a variant of own-rooted culture with a load of shoots of 36-40 pcs/bush. In the investigated variants, the highest concentration of phenolic substances was in wine from self-rooted grapes with a load of 36 ... 40 shoots per bush - 4130 mg/dm3. This had a positive effect on the organoleptic evaluation of this sample. The maximum total content of substances from a number of biologically active substances was found in wine from grape raw materials obtained from the grafted culture (134.9 ... 147.9 mg/dm3). According to the results of two years of research, the optimal concentration of biologically active substances in the range of 120-135 mg/dm3, which, in combination with other wine components, is able to provide the best quality of dry red wine. In 2018-2019 from the organoleptic point of view, wine materials from grapes of own-rooted culture proved to be of the highest quality. This advantage over the grafted crop was traced in all variants of rationing the load by the shoots of grape bushes.