Anotace:
Photosynthetic activity in the leaf of ten grape varieties was studied in the conditions of the northern part of Forest-Steppe of Ukraine. From 2019 to 2020 meteorological data were recorded by the ‟Meteotrekˮ meteorological station. The influence of weather conditions of the spring-summer period at the beginning of the vegetation phases, which in 2019 took place on average 12 days earlier than in 2020, was noted. Analysis of changes in the induction of chlorophyll fluorescence (ICF) in leaves revealed the more efficient use of quantum energy of absorbed light by F0 in the leaves of most varieties was noted in the phase “the beginning of berry ripening”. During the three periods of the study, the varieties Aromatnyj, Zagadka, Ilichevskij rannij, and Kardishah showed a lower content of chlorophyll molecules, which do not have a functional connection with the reaction centers (RC). According to the Fp index the highest intensity of photosynthesis on average for all varieties was observed in the phase “the beginning of ovary growth”, the lowest – “the inflorescence is visible”. The potential productivity of grape plants determined by the ICF coefficient for all varieties was at a very high level and had a weak or moderate correlation with weather conditions during the growing season. The hydrothermal coefficient and Σ act t ≥10 °С had a weak effect on the efficiency of the light phase of photosynthesis (Ki) and a noticeable one (correlation coefficient r = 0.50 – 0.69) on the efficiency of dark photochemical processes (Rfd) in the leaves of most grape varieties.