STUDY ON SOME CULTURAL PRACTICES TO INDUCE LATERAL BUD EMERGENCE IN APPLE TREES GROWN UNDER WARM CONDITIONS

Various cultural practices were applied to apple trees (Malus domestica Borkh.) grown under warm condition. The experiment was done in Japan and Thailand. In Japan 1-year-old cv Fuji (on M26) and cv Kogetsu (own root) apple trees were put in the glasshouse (15° to 25°C). These trees were treated as follows; 500 ppm paclobutrazol (PP333) applied on 4 occasions, defoliation, 6-benzylamino purine (BA) + notching alone and in combination. In Thailand 3-year-old cv Anna apple trees (on unknown rootstock from Indonesia) grown on the high mountain in the northern part were used. Treatments were single and combination of notching and two kinds of cytokinins, BA (100,200,500 ppm) and N-phenyl-N'-(2-chlor-4-pyridyl) urea (4PU-30) (25,50,100 ppm).

In cv Fuji, BA-combination treatment gave good results compared to non-BA combination treatments, and BA alone gave the best result. Defoliation seemed to have little effect in inducing lateral shoots while PP333 failed to increase lateral branching. In cv Kogetsu, control and paclobutrazol had no effect on bud emergence. The others seem to give better results but there were no differences between them. For cv Anna, treatments that had high concentrations of both kinds of cytokinins seemed to give better results than the other treatments.