Shaping and pruning techniques of slender spindle-shaped young trees of apple

Pruning Techniques of Apple Slender Spindle Young Trees

At present, apple slender spindle tree has become the mainstream in new apple planting areas. In order to provide reference for fruit growers, the author introduces the main points of shaping and pruning techniques of slender spindle apple trees according to his working experience in recent years.

Figure 1 Apple slender spindle tree

1. Shaping and pruning of seedlings in the current year

The formed apple tree is slender and spindle shaped, about 3m high, with upright and strong central trunk, crown diameter about 1.5 m, trunk height about 60cm, and about 30 small main branches evenly planted on the central trunk, opening angle 90~110°. The diameter of the main branch is less than 1/3 of the diameter of the central trunk at the place where it is attached. The main branch is distributed with fruiting branches and no branches. The whole main branch is actually a horizontal to pendulous fruiting branch group.

1.1 Cultivate strong central stems

In the first year of seedling planting, the seedlings should be stemmed according to their quality. The seedlings with height of 1~1.5m can be truncated at the position of 0.6~0.8m full bud; the seedling height of 1.5~1.8m can be truncated at the height of 1.2m; the seedling height is more than 1.8m, and the branches with thickness more than 1/3 of the trunk should be removed; the seedling height is less than 1m, and the full bud should be truncated at 0.5m, and the treatment should be carried out in the second year. If the central trunk grows into a double-headed or multi-headed one in summer after stem determination, one strong branch shall be selected as an extension head, and competitive branches shall be cut off. In order to make the center stem straight, a bamboo pole or steel pipe can be tied to the tree to assist growth.

1.2 cultured shoot

Before germination in spring, bud was carved every 5~6 buds on the central stem, and wound was carved above the bud to promote the branching of the central stem, and the main branch could slow down the growth potential of the branch. Thinning branches below 50cm from the ground on the trunk reduces nutrient consumption. When the main branch is 20~30cm long, open the angle to 90~110° with a protractor. The opening angle of the strong growth potential is larger, and the opening angle of the weak growth potential is smaller. The main branch is softened once at intervals, and the sprouted back branch is kneaded to droop in time.

1.3 Twisting, picking, defoliating.

In order to control the main branch to extend too fast, the main branch over 60cm is removed from the core and leaves, the top of the branch is pinched off, and then 3~4 leaves are removed, leaving petioles. In the middle and late July, the base of the branch is rotated to make it slightly droop, controlling its growth potential. In the middle and late August, the branches that are not in place should be pulled to ensure that the angle of the main branches is controlled between 90 and 110°. Generally, the branches are pulled into horizontal shape, and the branches that are too thick and too prosperous are pulled into 110°, showing a slightly drooping state.

2. Shaping and pruning of young trees in the second year

2.1 Spring Branch Treatment

The management of annual branches on the central trunk is the same as that of the first year. Before sprouting, the transverse branches and weak branches which turn and droop in July of last year are divided into lanes and circumscribed, the vigorous branches are carved into buds, the upper buds on the back are carved after the buds, the lower buds on the side are carved before the buds, and the branches turn and droop before the buds sprout, the front terminal buds are broken off, and the top is suppressed to promote the germination. For the weak branches on the transverse branches, the top of the branches less than 15cm long is suppressed and strengthened, and the branches more than 15cm are turned again in the middle. Before and after sprouting, bud was carved on the bud to promote short fruit branch.

2.2 Keep the center stem dominant

Cut off the main branches whose thickness exceeds 1/3 of the central trunk and the branches that compete with the central trunk, keep as many branches as possible from the central trunk, adjust the position and angle of the main branches reasonably in summer, so that the main branches are reasonably arranged on the trunk, arranged spirally according to the space, and do not affect each other.

2.3 Control the growth potential of main branches

Only fruiting branch group is left on the main branch. If there are many dorsal branches on the main branch, part of them can be thinned appropriately. When the remaining 15~20cm long, the base is twisted and the branches are softened continuously. The horizontal twigs on the main branch are 15cm long when they are picked, and the length is controlled to promote strength. In the middle and late August, the main branches of the current year are pulled, and the angle of pulling branches is the same as that of the first year.

3. Shaping and pruning of young trees in the third year

3.1 Continue to maintain the advantage of the center trunk

Cutting off the branches competing with the central trunk, the growth of the extended branches of the central trunk reached more than 80cm, and the tree height finally reached about 3m.

3.2 Control the growth potential of main branches

The strong main branches with vigorous growth potential and premature germination of short branch terminal buds in early June are circumcised every 15~20cm, and 30 times amino acids or fruit tree regulator PBO can be sprayed to control the growth potential, promote a large number of short branches, and some can form flower buds.

3.3 branch treatment

The pruning management of trunk annual and biennial branches is the same as that of the first and second years. The thicker central trunk was cut one circle above 15cm to control the upper strength. After July, thinning the long branches, dense upright branches and slender branches in the bore, saving nutrition and improving ventilation and light transmission conditions. In the middle and late August, the main branches of the current year are pulled, and the angle of pulling branches is the same as that of the first and second years.

3.4 Vigorous main branch promotes growth and restraint branch

Before the vigorous main branch sprouts, two bud rings are reserved at the base to promote the growth of restraining branches, and the nutrients transmitted from the branches to the front end are distributed to slow down the excessive growth of the branches due to the excessive prosperity of the front end. The branches thinner than chopsticks are cut into 1 circle, the branches thicker than cigarettes are cut into 2 circles, and the branches thicker than pinkie fingers are cut into 3 circles. Circle spacing up to leek leaf width.

After 3 years of pruning, the newly planted apple trees basically form a slender spindle tree shape, the trunk is obvious, the tree height is about 3m, and about 30 small main branches are evenly planted on it. The main branches over 70cm long should be pruned to make them slightly drooping, and the crown diameter should be controlled to expand. Fruiting shoot groups are attached directly to the main branches. The main branch and central trunk are obviously different, and some flowers and fruits begin to appear (Fig. 2 and Fig. 3).

Fig. 2. Slender spindle apple tree flowering

Fig. 3 Fruit bearing shape of slender spindle apple tree (Yangzhuang, Wu 'an City)