The effect of meteorological factors on apple tree productivity in the Piedmont zone of Crimea
The results of study of four apple varieties (‘Krasnoye Ranneye’, ‘Vista Bella’, ‘Cimmeria’, ‘Tavria’) are presented. On its basis the varieties are classified by the time of flowering. The duration of flowering of the studied apple varieties was changing over the years and had varietal differences. On average the period of flowering timed 8 - 14 days. The end of flowering in all studied varieties with the accumulation of the sum of effective temperatures above 5 °C was registered with values from 216 to 260 °C. The average daily air temperature varied from 7.1 to 14.8 °C. Periodic spring frosts damage the reproductive buds, the degree of their impact is significant. As a result of the conducted studies, a correlation between the average daily minimum temperatures and cropping capacity of early-flowering apple varieties was found. The average daily and minimum air temperatures have a great impact on early-flowering apple varieties, and for late-flowering apple varieties the correlation dependence on the amount of precipitation is determined. During the study period, night frosts of up to -2 °C, affecting the setting and cropping capacity of varieties, were observed. Frosts were registered in 2011, 2015 and 2017. The apple tree cropping capacity was determined as a cumulative indicator that depends on the number of reproductive buds, the number of flowers in inflorescences, the average number of set fruits and their weight, as well as the adaptability degree of the variety to stress factors. It was also noted that cropping capacity of the studied apple varieties was unstable and had varietal differences, the highest value of this indicator during the study period was noted in the ‘Tavria’ variety (66.6 t/ha).