Improving Nursery Tree Quality in Apples by Heading, Cytokinin and Gibberellin Applications

Abstract

The oldest and simplest branching method known is heading, a pruning technique. Although many alternative techniques have been developed, there is not yet an accepted branching method for all cultivars in practice. This study investigated the effects of heading and different plant growth regulators on the quality of 2-year-old nursery trees. The number, crotch angle, length and diameter of long branches (>25 cm) as well as trunk diameter and tree height were determined in four different apple cultivars (Mondial Gala/M.9, Golden Reinders/M.9, Starkrimson Delicious/MM.106 and Granny Smith/MM.106). Treatments containing both cytokinin and gibberellin increased branching compared to applications containing cytokinin only. To conclude, low-dose repeated cytokinin+gibberellin applications after budburst, especially in the Granny Smith cultivar, can be used effectively in commercial nurseries.