Induction of lateral branches in tree fruit nursery stock with propyl 3-t-butylphenoxy acetate (MB 25, 105) and Promalin (GA 4+7 + 6-benzyladenine)

Abstract

Sprays with 250–2000 mg l −1 propyl 3-t-butylphenoxy acetate (MB 25,105) and 250 and 500 mg l −1 GA 4+7 + 6-benzyladenine (Promalin) were applied to scion growth of first nursery trees of ‘Bartlett’ pear ( Pyrus communis L.), ‘Bing’ cherry ( Prunus avium L.) and ‘Oregon Spur II Delicious’ apple ( Malus domestica Borkh.) to stimulate lateral branching in the nursery. Most treatments significantly increased branching compared to untreated controls. Combination sprays of the two chemicals were usually better than either used alone. Chemical treatment usually produced greater branching and wider branch angles than mechanical heading. Both chemical and mechanical treatments reduced tree height and caliper, but the decrease was not always statistically significant.