TREE MANAGEMENT FOR SPUR AND FRUIT QUALITY

Spur leaf area of apple is important to bud development, fruit set, early fruit growth, and relates to the long-term productivity of many cultivars.
However, spur leaf area can vary 200% within one tree and is dependent upon genetic environmental and cultural factors.
Spurs of a single cultivar on 9 rootstocks at 4 locations in the US varied in leaf area, SLW, and leaf dry wt., depending upon both stock and location.
Spurs oriented vertically upright or horizontally were of higher quality than pendant spurs.
Spur leaf area, size, SLW, and dry wt. decreased from apical positions to basal positions on limbs.
Dormant pruning by heading back into 1 or 2-year-old wood tended to invigorate spur leaf development but reduce bud size.
Detailed spur pruning of thinning spurs to only 1 bud or removing entire spurs by stub cutting did not increase spur and fruit quality but tended to reduce production on a limb unit basis.
The use of the cytokinin 6- benzyl adenine (6BA) increased spur density on nonspur cultivars and tended to increase production 2 seasons after treatment.
The use of 6BA plus gibberellic acid after defoliation of greenhouse grown trees increased regrowth, spur development and flowering.

III International Workshop on Temperate Zone Fruits in the Tropics and Subtropics

Curt R. Rom

https://doi.org/10.17660/ActaHortic.1990.279.34