Phenological aspects of the development of sweet cherry varieties in the environmental conditions of the Right-Bank Forest-Steppe of Ukraine

Abstract

The article presents the results of the study of the seasonal rhythm of the growth and development processes of sweet cherry varieties in the conditions of the Right-Bank Forest Steppe of Ukraine. The beginning of culture development, passage and duration of the main phenophases are determined. There is slight varietal variability between the dates of the beginning and duration of vegetation in accordance with changes in weather conditions. As a result of the conducted observations, it was established that the beginning of vegetation of sweet cherry varieties takes place in the first decade of April. The beginning of flowering of cherry trees is noted in the first half of the third decade of April, the variation of cherry blossoming beginning over the years reaches 5–10 days, which is most typical for the example of the «Dar Mlieva» and «Drogan yellow» varieties. The onset of harvestable ripeness largely determines the variety's belonging to the ripeness group. The fruits of the «Mliivska yellow», «Dar Mlieva», and «Zoryana» varieties are the first to be harvested, and after 26 days, the fruits of the «Amazon» variety are harvested. According to the results of observations, sweet cherry varieties were conditionally divided into groups of ripeness: early ripening, in which the fruits ripen 44-48 days after flowering, medium ripening – fruits ripen 50–60 days after the end of flowering, late ripening – fruits ripen later than 60 days after flowering. Depending on the onset of the harvestable ripeness of the fruits and the duration of the fruiting phase, for timeliness and convenience of harvesting it became possible to create a kind of harvesting conveyor. The duration of the growing season was on average 186 days in the early-ripening group of sweet cherry varieties with the shortest period in the «Mliivska yellow» variety, 191 days for the medium-ripening group varieties with the longest period in the «Melitopolska krapchasta» variety and the shortest in the «Alyonushka» variety, in the lateripening varieties «Biruza» and «Amazon» varieties 196 and 200 days respectively. Key words: sweet cherry varieties, phenological phases, vegetation period, vegetative organs, duration of the growing season.