Improved feathering on apple nursery trees by BA application

Trials were carried out with the aim to improve lateral shoot formation on 'Idared' and 'Egri piros' apple nursery trees. This paper presents the results of trials from 1993 to 1996 concerning the optimal concentration, and number of repetitions of BA application. BA was applied in a water soluble formulation (Paturyl 10 WSC) containing 10% of BA. The treatments were applied to one-year-old apple trees budded on 'Malling 26' and 'Malling-Merton 106' rootstock. BA 0.02, 0.,04 and 0.06% was applied 3 to 6 times. BA was sprayed in June weakly to the upper third of 70-80 cm high trees combined with 0.2% Tween 20 detergent. Length and the number and quality of lateral shoots were measured and evaluated at the end of September. BA treatments were effective in breaking dormancy of summer buds of one-year-old apple nursery trees and caused different lateral shoot formation. The number of repetitions of BA application proved to be important, influenced the number and total length of laterals. No influence of different repetition number was found on average length of laterals. Spraying 0.04% BA to Idared trees most effective was the repetition five times but the treatment with four times repetition resulted similar number of laterals and shoot growth. Based upon these results 0.04% BA sprays could be recommended repeated five times. For 'Egri piros' trees the higher than 0.02% BA concentrations proved to be more effective on the total number of lateral shoots and on total shoot growth, but these treatments reduced the average length of shoots.