Abstract:

To provide a new theoretical support for the pruning technique on apple for early bearing, high and stable yields, the author proposed innovatively and proved qualitatively a deeper pruning theory based on the circuit principle in physics with the apple tree structure diagram as material. The theory included three points: (1) The pruning method of increasing resistance and decreasing current of apple tree could obtain early bearing, high and stable yields; (2) Thinning any branch above rhizome would increase the resistance of tree, on the contrary, short cutting would decrease it; (3) Thinning a large branch with low resistance would have a larger increase amplitude of tree resistance than a small branch with high resistance whose basal part was in the same shoot with the former. Furthermore, the author explained the theory specifically and conducted an application test about it during 2004-2010. The results showed that: In young apple orchard applied the theory ,the flowering plant ratio of 4 cultivars reached to 75% and that of the other 9 was 50% among 13 cultivars, whose initial fruit-bearing stage was 1-2 years earlier than under the condition of conventional management; In full fruit-bearing ‘Fuji’ apple orchard applied the theory, the average yield of 6 years was 49203 kg/hm2 which increased 54.4% than the control, and this orchard could be appraised as high, stable yielding also for its biennial bearing index of 6.1%~18.6% , while the control orchard was appraised as very unstable yielding for that of 121.8%~428.8%, moreover, its per unit area yield of 2008 and 2009 trended towards decrease. It was clear from the foregoing that the pruning theory created by the author was very effective in obtaining early bearing, high and stable yields.