The effect of agronomic practices and terroir on the phenolic complex of autochthonous grape variety ‘Kefesiya’

All-Russian National Research Institute of Viticulture and Winemaking Magarach of the RAS, 31 Kirova Str., 298600 Yalta, Republic of Crimea, Russian Federation

^* Corresponding author: cod7-4orever@mail.ru

Abstract

This study aimed to assess the cropping capacity, quality indicators, and phenolic compounds in various tissues of the ‘Kefesiya’ grape variety, influenced by cultivation terroir and agricultural practices. Results indicate that bush training methods, trunk height, and green operations significantly affect cropping capacity, quality, and phenolic content. A multi-armed fan training on a medium trunk in the Sudak terroir yielded 1.8 times higher cropping capacity compared to a one-sided Guyot on a high trunk in Alminskiy. Combining topping with defoliation increased sugar content by 15% and reduced titratable acids by 24% in Sudak, while in Alminskiy, sugar content rose by 5% and acids decreased by 9%. However, this combination also led to a decrease in phenolic compounds across both terroirs. Topping and defoliation positively correlated with phenolic compounds, especially catechins. The study highlights that grape quality and phenolic accumulation are influenced not only by soil and climate but also by specific agricultural practices tailored to crown management.