Planting Density and Application of BA for the Production of Well-feathered Bi-axis Apple Trees

In order to produce bi-axial feathered apple trees economically and stably, unsaleable, low-quality whip apple trees were planted at different density levels and headed ca. 3 cm above the grating union, with two shoots raised for the axes. When the shoots reached a height of about 60 cm, BA was sprayed at different intervals and times. In terms of the planting distance, increasing the inter-row distance from the conventional distance of 1.0 m to 1.2 m did not have a significant effect on the tree height, scion diameter or number of feathers per axis. Nor did it increase the yield rate of saleable bi-axial apple trees. The inter-row spacings was 0.3, 0.4, and 0.5 m, and the scion diameter tended to be somewhat thicker as they were planted more widely, but there were no significant differences in the tree height or number of feathers per axis. In the 600 ppm BA treatment to induce feathers, among the spraying intervals of 7, 10, and 14 days, the 10-day interval led to the highest number of feathers per axis (16.1). Regarding the number of BA sprays, as the number of BA sprays was increased to three times instead of one or two times, more feathers were induced. In conclusion, in order to produce biaxial geodesic seedlings economically, the strategy of planting at a planting distance of 1.0 x 0.3 m and spraying BA three times at 10-day intervals is most appropriate.