Changes in the uvological parameters of young Amur grape plants

This article reports a study into Amur and Euro-Amur grape varieties. The former included ‘Amurskij Triumf’, ‘Amurskij Proryv’, and ‘Proryv Belyj’, while the latter included ‘Neretinskij’, ‘Marinovskij’, and ‘Severnyj Plechistik’. The aim was to investigate changes in the uvological parameters of young Amur grape plants. The mechanical and chemical composition of bunches and berries of Amur and Euro-Amur varieties were analyzed using N. N. Prostoserdov’s approach to uvological estimation of varietal samples. The bunch weight, berry weight, seed weight, skin weight, and rachis weight, as well as the indicators of bunch structure, bunch composition, berry stacking, and berry structure were determined. In most varieties, the average weight of berries during the 2022-2023 period increased. Among the studied Amur genotypes, the largest berry was observed in ‘Amurskij Triumf’ (1.5 g) in 2022 and ‘Severnyj Plechistik’ (2.1 g) in 2023. The highest bunch weight on young plants was observed in the second year of fruiting in ‘Proryv Belyj’ (326.0 g), ‘Amurskij Proryv’ (272.6 g), and ‘Severnyj Plechistik’ (281.8 g). The indicator of seed weight per 100 berries in most varieties increased slightly in the second year of fruiting compared to the first year. In the second year of fruiting, the minimum and maximum seed weight in 100 berries was observed in ‘Amurskij Proryv’ (10.9 g) and ‘Amurskij Triumf’ (22.4 g), respectively. The quality of grape juice was evaluated. The studied grape plants belong to technical varieties and are characterized by small-size berries (1.2-2.1 g), increased levels of titratable acids (7.9-16.6 g/dm3), and an optimal sugar content in berries (up to 23.3 g/100 cm3). The varieties show different uvological parameters under the influence of external conditions. The ‘Proryv Belyj’ variety was found to be optimal for winemaking and juice production in terms of the sugar and titratable acid ratio. Further research is required for a comprehensive uvological characterization of the studied varieties.