DWARFING EFFECTS OF THE CLOSE PLANTING OF APPLE TREES GRAFTED ON SEMI-DWARFING AND VIGOROUS ROOTSTOCKS

A. Mika, D. Chlebowska, J. Kosmala
Growth and cropping of a few apple cultivars grafted on semidwarfing and vigorous rootstocks were compared in a number of spacing trials. The trials included apple cultivars: Melba, James Grieve, Wealthy, Lobo, Jonathan, Bancroft and Starking. Trees were grafted on semidwarfing rootstocks M 7, MM 106, and on vigorous M 11, MM 111, A 2 and Antonovka seedlings. The spacing treatments varied from 400 to 1 600 trees per ha. Trees planted at close distances between the rows (3–5 m) were trained as espaliers, while trees planted with larger distances between the rows (6–7 m) were trained in round bush forms.

Within 6–8 years after planting, dwarfing effects of close planting were apparent. Close planting reduced extension growth, stem sectional area, weight of winter prunings, number of fruit buds, and yields from individual trees.

When the number of trees per hectare were doubled, the stem sectional area and the weight of winter prunings was reduced by 20–30 %. Yield per individual tree declined with increasing density. When the number of trees per ha was increased 4 times, the peak yield per tree was reduced to 1/5. Weak growing cultivars grafted on semidwarfing rootstocks reached the ceiling level of yield within 6 years at the densities 1 200–1 600 trees per ha, 8 years at the densities 900–1 000 trees/ha, 10 years at the densities 600–800 trees/ha, and over 15 years at the density 400 trees/ha. The peak yield per tree was relatively around: 20 kg, 30 kg, 45 kg and 90 kg. Strong growing cultivars grafted on vigorous rootstocks reached the peak yield within 8–10 years, even at the largest planting distance (400 trees/ha).

In the early lifetime of the orchard the highest yields per ha were obtained with the highest densities. Later, very close planting had an adverse effect on the yield and fruit quality. The best results were obtained with weak growing cultivars planted at the densities 600–800 trees per ha. Dwarfing effects of dense planting helped to maintain the orchards in a productive and manageable state for 15 years.

Mika, A., Chlebowska, D. and Kosmala, J. (1981). DWARFING EFFECTS OF THE CLOSE PLANTING OF APPLE TREES GRAFTED ON SEMI-DWARFING AND VIGOROUS ROOTSTOCKS. Acta Hortic. 114, 143-143
DOI: 10.17660/ActaHortic.1981.114.16
https://doi.org/10.17660/ActaHortic.1981.114.16

Acta Horticulturae