Enhancing feathering of one-year-old Gala and Jonagold apple trees through application of 6-benzylaminopurine and gibberellins

Abstract

© 2015, National Centre for Agrarian Sciences. All rights reserved. In apple, synthetic cytokinin 6-benzylaminopurine (BA), either alone or combined with gibberellins 4+7 (GA<inf>4+7</inf>), plays an important role in overcoming apical dominance and in the production of well-feathered apple nursery trees. The solutions of BA and BA+GA<inf>4+7</inf> corresponding to the concentrations of 250, 350 and 450 μl l^-1 of active ingredient (BA) were applied three times at 7-day intervals during vegetative period. Feather formation is strongly influenced by type and concentration of plant growth regulators. Increasing concentrations of BA and BA+GA<inf>4+7</inf> led to a greater number of feathers, increased feather length, and expanded branching zone. Applied in combination with GA<inf>4+7</inf>, BA has stronger positive effect on total feather number, feather length, branching zone and tree height, than when applied alone. Compared to BA+GA<inf>4+7</inf>, BA has a stronger effect on the growth rate of the shoot, resulting in a greater feather angle and a lower tree height, which can be eliminated by addition of GA<inf>4+7</inf>. The treatments also had different effects on trunk diameter. In Gala, a minor adverse effect of BA on trunk diameter was noted, whereas it was positive in Jonagold.