M. Meland, O. Hovland
An intensive orchard of 'Summerred' apple trees (Malus domestica Borkh.) was established in 1990 at Ullensvang Research Centre, western Norway at 60° North to evaluate five planting systems (free spindle/M.9, slender spindle/M.9, Y-trellis/M.26, V-system/M.9 and vertical axis/M.26). The experiment was located on a sandy soil and trickle irrigation was provided. Soil management was grass in the alleyways and herbicide strips 1 m wide along the tree rows. Planting distances for free spindle, Y-trellis and vertical axis trees were 2 x 4 m (1250 trees/ha), slender spindle 1.5 x 4 m (1670 trees/ha) and V-system 1.0 x 4 m (2500 trees/ha). During the first years, yields/ha were positively correlated with tree density. Cumulative yield per hectare was highest on V-system trees. Free spindle trees produced only half of that yield. Y-trellis trees produced less over the two first cropping years due to smaller canopy volume. The yield the sixth growing season on V-system trees was 29 t/ha and Y-trellis trees produced 27 t. Yield efficiency was in average greatest for the slender spindle trees. The vertical axis trees had significantly smaller apples than the other canopy systems. The content of soluble solids, ground and surface color were little influenced by training systems except for the vertical axe and Y-trellis trees where high yields significantly reduced the flavor and sugar content of the apples.
Meland, M. and Hovland, O. (1997). HIGH DENSITY PLANTING SYSTEMS IN 'SUMMERRED' APPLES IN A NORTHERN CLIMATE. Acta Hortic. 451, 467-472
DOI: 10.17660/ActaHortic.1997.451.53
Apple, production systems, yield, yield efficiency, fruit size, soluble solids

Acta Horticulturae