Growth and Fruiting Responses of ‘Redspur Delicious’ Apple Trees to Pruning Treatments

Abstract

Abstract A 7-year pruning trial with ‘Redspur Delicious’ trees (Malus domestica Borkh.) compared growth and fruiting responses to 3 pruning systems: 1) trees pruned with structural limbs spaced around a central leader and 20 cm apart vertically (regularly pruned); 2) central leader trees with structural limbs in tiers and one-year-old wood headed annually (tiers and heading); and 3) trees trained as slender spindles. Heading increased shoot growth from one-year-old wood but not every year. Generally, the growth response was limited to the first 6 subapical buds behind the heading cuts. Heading reduced the number of nodes on one-year-old wood, forced some lateral buds to produce vigorous shoots, and removed the apical section of wood which was shown to be more productive than the subapical sections. Cumulative yields of the slender spindle and regularly pruned trees were comparable, and both were higher than those of trees pruned by the tiers and heading system.