Notching Techniques Increase Branching of Young Apple Trees

Apple trees ( Malus domestica Borkh.) were notched with a hacksaw blade by removing a 2-mm-wide strip of bark from directly above a bud. The cut extended down to the secondary xylem and around about one-third of the circumference of the stem. The most effective time to notch was ≈2 to 4 weeks before full bloom. Notching was most effective at inducing shoot growth from buds on the top of a branch, less effective for buds on the side, and least effective for buds on the underside of a branch. On untreated controls, the most shoots grew from the upper one-third of 1- or 2-year-old growth, and very few shoots developed buds on the lower one-third. If a bud was notched, however, the pattern was similar and incidence of shoot development was high. The percentage of notched buds that developed into shoots was not influenced by wood age.There was a positive, linear relationship between bud size and the percentage of buds growing into lateral shoots and between bud size and the length of those lateral shoots. Over all years, experiments, and cultivars, notching increased shoot production ≈600%.