GROWTH, FRUITING PECULIARITIES AND EFFICIENCY OF CULTIVATION OF UKRAINIAN APPLE CLONES (MALUS DOMESTICA BORKH.) OF THE 'JONAGOLD' VARIETY

Purpose. On the basis of a comprehensive study of the characteristics of growth, development, fruiting and quality of the fruits of spontaneous mutants of the apple tree (Malus domestica Borkh.) of ‘Jonagold’ variety, select clones which differ from the original variety in tree growth strength and are superior in yield, marketability, fruit keeping quality and economic production efficiency of the latter.

Methods. Field, laboratory, comparison, generalization and mathematical statistics.

Results. The results of studying the growth and fruiting characteristics of 20 Ukrainian spontaneous clones of ‘Jonagold’ variety in the conditions of the Western Forest-Steppe of Ukraine are presented. It is revealed that plants of the studied clones did not differ in terms of beginning and duration of the main phenological phases and vegetation period from the varieties widely distributed and well adapted to Podillia conditions. The harvesting ripeness of the clone fruits came in the second or third decades of September with a difference of seven days. Trees of most clones (DP-4, DP-5, DP-9, DP-10, DP-13, DP-14 and DP-17) were medium-growing. The yield of five to eight-year-old clone plantations was 12.1–32.3 t/ha, which provided cost-effective cultivation in the conditions of Podillia, the level of production profitability was 66–242%. All spontaneous mutants formed fruits larger than average size (except for DP-20, forming large ones), which are beautiful, elegant and vary in the intensity and character of the skin color depending on the clone. The clones DP-1, DP-3, DP-17, DP-18 and DP-19 were distinguished by a high yield of fruits of the highest and first grade.The clones DP-1, DP-3, DP-17, DP-18 and DP-19 were marked by the highest yield of apples of the higher and the first commodity grade, and this property was significantly superior to the yield of the control variety. The tested clones are divided into three groups according to the fruit ripening dates: early winter, winter, and late winter.

Conclusions. A long-term assessment of the objects of study revealed that the biological properties Ukrainian clones of ‘Jonagold’ variety correspond to the climatic conditions of the Western Forest-Steppe ofUkraine. Most of them belong to the medium-growth group (DP-4, DP-5, DP-9, DP-10, DP-13, DP-14 and DP-17) and are characterized by a mixed type of fruiting. Clones DP-1, DP-3, DP-17, DP-18 and DP-19 were distinguished by a high yield of fruits of the highest and first commodity grade. According to the main indicators of fruit quality, clones DP-3, DP-8, DP-13, DP-14, DP-16, DP-17, DP-18 and DP-20 were recognized as the best; the highest economic efficiency of apple production in Podillia was provided by clones DP-14, DP-17, DP-18 and DP-19. The latter ones are recommended for registration in “The State Register of plant varieties suitable for dissemination inUkraine”, as promising clones for introduction into planting for the production of fruits of universal purpose in the zone of the Western Forest-Steppe ofUkraine.