Selective inhibition of flowering on 'Braeburn' apple trees with gibberellins

Abstract

'Braeburn' apple trees were treated with GA3 or GA7 at either 100, 200, or 400 mg·L-1, 2 years after being grafted onto 4-year-old 'Royal Gala'/MM.106 trees in order to evaluate their effects on flower bud formation. Inhibition of flowering was observed on 1-year wood only and not on spurs in response to GA treatments applied later than 6 weeks after bloom. GA7 was a more potent inhibitor of flowering than GA3. These results indicate that GA treatments may provide a useful technology for the selective removal of flowers from 1-year wood in apple and may also provide a useful tool for overcoming biennial bearing in apple by inhibiting flower bud formation when applied in the light-cropping year of the biennial cycle.