Effects of planting system, tree shape, and additional summer pruning on growth, production and flowering of apple trees at high plant densities

Abstract

SummaryTwo tree shapes, the slender spindle and the North-Holland spindle, were studied in four planting systems (single row, three-row bed, six-row bed, and full-field) at high plant densities. Additional summer pruning was applied to half of the trees in each system. The trial was performed with apple cv. Red Boskoop on a soil type characterized by moderate growth vigour. The trunks of the North-Holland spindle grew less than those of the slender spindle. Plant density and pruning intensity were negatively correlated with trunk-basal area increment. The North-Holland spindle, which had nearly 500 more trees per ha, yielded as much as the slender spindle. For a given density the North-Holland spindle yielded less than the slender spindle. Yield efficiency, expressed as cumulative yield per unit of final trunk-basal area, was also lower for the North-Holland spindle. However, per unit of crown volume, this spindle type produced considerably better. The additional summer pruning did not affect yield or yie...