THE RELATIONSHIP BETWEEN THE SIZE AND QUALITY OF APPLE FRUIT HARVEST AND METHODS FOR INCREASING THEM IN THE CONDITIONS OF SOUTHERN EUROPEAN RUSSIA

The work is devoted to determining the optimal ratio of the size and commercial quality of the apple fruit harvest, as well as possible agricultural methods to increase them in the southern region of Russia. The research was carried out in laboratory and field experiments conducted in the plantations of JSC «Sad-Gigant», located in the plavnevoy subzone of the Prikubanskaya gardening zone of the Krasnodar Territory in 2018–2023, the soils are alluvial meadow. The optimal yield of the leading industrial apple cultivars (cultivar groups) in the south of European Russia was determined, associated with a maximum (at least 88 %) yield of fruits with a diameter of more than 55 mm. In particular, for very large-fruited cultivars of ‘Fuji’ and ‘Green Star’, this indicator should be 80–85 t/ha, and for cultivars belonging to the group of "potentially large-fruited" (‘Golden Delicious’, ‘Grani Smith’, ‘Florina’, ‘Tsivg 198’) – only 70–75 t/ha. The noted results are guaranteed in plantations with optimal tree density and relatively favorable weather conditions. To solve the two-pronged task of increasing the yield and marketable quality of apple fruits (for example, ‘Golden Delicious’ cultivars) in years with the manifestation of temperature stressors, the prospects of using non-root top dressing with the organomineral fertilizer «Chelate Antistess» a week after flowering, which provides an increase in fruit diameter by 2.5 %, and an economic harvest by 14.7 % compared with control values, were proven.