Key cultivation techniques for growing peach, apricot and plum that flower and bear fruit on the same tree

To meet people's need for enjoying both flowers and fruit, we used peach trees as rootstock and grafted early-, mid- and late-maturing plums, apricots and peaches onto the same tree. After 4a (years) of trials, complete success was achieved: in the year of grafting a certain crown formed and flowering occurred, in the 2nd year each tree bore 70-80 fruits, the flowering period lasted about 45d (days), the full-bloom period reached about 25d (days), and the fruit-bearing period lasted as long as 6 months. It allows enjoyment of both flowers and fruit, and the fruit can be eaten as well, and it is deeply loved by the general public. The key techniques are summarized below.

1 Cultivation of rootstock seedlings

For open-field rootstock seedlings, 3-4-year-old wild peach (Prunus persica) should be selected, and the tree should be trained and pruned 1a (year) before grafting. Three main scaffold branches and a central leader are required to be retained, and the main branches should be evenly distributed, preferably in the 3 directions of southeast, southwest and due north, but shaping according to the tree should also be considered. Pruning adopts heavy heading-back; each main branch (including the central leader) must retain at least 5-6 pruning positions (the grafting positions for the following year) so as to force out vigorous 1-year-old shoots for grafting.

For potted rootstock seedlings, 2-3-year-old wild peach with a well-developed, intact root system and vigorous growth should be selected as rootstock, headed at about 40cm at a plump bud; if there are side branches they should be retained, and heavy heading-back should be carried out at plump buds, with appropriate training and pruning as required. Then plant it in a prepared flower pot (both pot height and diameter should be greater than 60cm); the planting depth should not be too deep, and the depth of the original soil surface in the field is appropriate; then water it and place it in a sunny, wind-sheltered spot. The best planting time is after the soil thaws in spring and before the peach tree buds.

For the selected rootstock trees, after the seedlings bud, retain 3-4 side branches on each main branch and 4-5 vigorous buds on the central leader as the grafting positions for key cultivation, and the retained branches should be arranged in directions spaced as far as possible at 15-20cm intervals. When new shoots grow to 30-40cm, pinch off the tips; afterward, each time secondary shoots grow to 10-15cm, repeat the pinching to increase new shoot thickness, and pay attention to applying quick-acting nitrogen fertilizer in small amounts several times to promote accelerated growth. If the growth angle of new shoots is too small, bending the branches appropriately to increase the angle is acceptable, preferably not exceeding 45°. During the growing season, water in a timely manner and pay attention to controlling aphids; every 7d (days) spray once a mixture of aphid-killing agent and high-quality foliar fertilizer to control insects and promote growth.

2 Grafting at the right time and by the right method

After the rootstock seedlings grow vigorously for 1a (year), before bud break the following spring, use the multi-head top-grafting method to convert the rootstock seedlings in one operation. Practice has proved that grafting 16-20 positions on the whole tree of 3-4-year-old trees gives a high survival rate, rapid crown expansion and early entry into the fruiting stage. The grafting methods can use single-bud or double-bud side-veneer grafting and cleft grafting. Wrap with 2-3cm wide plastic film exposing the buds (wrapping both the scion and the graft union completely); to be safe, after wrapping with plastic film, plastic twine can be used to reinforce the graft union.

3 Cultivar combinations and grafting positions

3.1 Cultivar combinations

For wild peach, the main cultivars are Shazizaosheng, Xinchuanzhongdao and Zhonghuashoutao; for nectarine, the main cultivars are Shuguang, Yanguang, Tedayouwang and Wanshouhong; for plum, the main cultivars are Dashi Zaosheng, Angenuo and Heibaoshi; for apricot, the main cultivars are Shiguan Zaohong, Hongfeng, Xin Shiji and Kaite Apricot.

3.2 Grafting positions

The three main branches are grafted respectively with the 3 tree species of peach, apricot and plum, and the central leader is grafted with the 2 tree species of plum and apricot. Because peach has a relatively strong light preference, peach cultivars are grafted on the south side or a slightly south-facing direction, while plum and apricot are grafted on a slightly north-facing direction. The cultivars grafted on each main branch follow the principle that early-maturing cultivars are on the inside, mid-maturing cultivars in the middle, and late-maturing cultivars on the outermost side; the closer the grafting position is to the base of the main branch, the better, as sprouting ability is strong and growth is fast.

4 Scientific management of grafted trees

After the grafts survive, promptly remove the sprouting buds on the main branches and on the rootstock other than the grafted buds, so that nutrients are concentrated and the grafted buds are prompted to sprout. After the grafted buds sprout, increase fertilizer and water management; when new shoots grow to 10-15cm, pinch off the tips to promote branching; when secondary shoots grow to 20cm, pinch repeatedly to promote flower formation. At the same time, carry out foliar fertilizer spraying once every 7d (days), with nitrogen, phosphorus and potassium applied in combination. In the 2nd year, if the tree grows too vigorously, multiple pinching can be carried out and branch bending adopted to weaken vigor, combined with spraying paclobutrazol to control new shoot growth, promote abundant flower formation and smoothly enter the high-yield period. At the same time, attention should be paid to timely control of pests and diseases such as aphids, red spiders, peach fruit borers, peach fruit moths, scale insects, Alternaria leaf spot, bacterial shot hole and gummosis.