High grafting method and matching Management of Nanguo Pear

In recent years, with the popularization of a series of Nanguo pears (Dananguo and Hongnanguo), in order to quickly adapt to the change of pear variety market, we improved 3500 hybrid pears in 2002. Due to the management technical measures in place after grafting, the survival rate of high grafting reached 95% in that year, the tree potential was restored the following year, and the yield of the original pear orchard was basically restored in the third year, with good results. The high connection method and its supporting management technology are introduced as follows.

1 high connection method

1.1 High-rise period

In the semi-arid area of northwest Liaoning, the spring is the most suitable for the high grafting of hybrid pears to Nanguo pears, and the specific time should be controlled after the sap flow, that is, from late March to late May, but there must be better conditions for preservation of scions in the later stage. Scions must not sprout, otherwise the survival rate of high grafting will be reduced.

1.2 High connection technology

1.2.1 the treatment of high grafting site and its backbone branches for perennial hybrid pear trees with high connection to Nanguo pear, the backbone branches are usually selected according to the open hierarchical tree structure of the three main branches at the base, and do not strongly change the shape of the tree if the tree shape is irregular, the high grafting site is generally controlled below the 4-6-year-old branch, or the branch diameter does not exceed 6cm, do not "cut down", otherwise the wound is too big and not easy to heal.

1.2.2 High grafting method is often used for high grafting of hybrid pear to Nanguo pear. The specific method is to cut off the branch where the rootstock is to be split, cut the saw, cut a long 5~6cm cut vertically in the middle or near one side, then cut the scion, and also cut a wedge-shaped surface of about 3~4cm at the symmetrical part of the base of the scion, the cutting surface should be flat, and one side is slightly thicker. Three or four buds were left on the scion and then cut off from the upper part, and the cut was flat in order to reduce water evaporation. Insert the cut scion into the branch split of the rootstock, slightly thicker one side outward, align the rootstock cambium, tie it tightly with plastic strip, seal the cut on the scion with protective agent and cover it with plastic bag to maintain humidity. When the rootstock is thicker, one split interface can be connected with two scions.

2 make up and unbind in time

2.1 Supplementary connection

The survival of hybrid pear can be determined after 20-25 days of grafting Nanguo pear. The grafted Nanguo pear remained green and the buds began to sprout, while the grafted Nanguo pear showed wrinkled and dry skin. The high grafting that did not survive should be repaired in time, the method is to cut off the dead pile in spring and then split it, and after the fruit tree is peeled in early summer, the method of green branch grafting can be adopted. Paper bags should be put on in time after reconnection to facilitate survival. Cover the bag with a plastic bag. Plastic bags are used because the external temperature is too high at this time, and the scion is easy to lose water because of the high temperature.

2.2 unbind

When the Nanguo pear grafted or replenished in spring enters the rapid growth period from June to July, the plastic strip should be unbound in time; for the high grafting in spring, when the plastic bag is used, the plastic bag should be torn gradually when the tip grows 2 or 3 leaves, and the plastic strip should be untied after the grafting site is healed.

(3) de-cute and entrapment.

3.1 removing cuteness

For the spike tip of Nanguo pear which survived by high grafting, the sprouting of the original variety under the grafting interface should be removed in time, 5-7 times in the whole year, and de-sprouting once a week.

3.2 lead and bind

For the surviving Nanguo pear shoots, the strut should be used in time, when the new shoots reach 25~35cm, a pillar should be attached at the grafting site, and the Lignification interface of the new shoots should be removed after healing.

4 strengthening the management of fertilizer and water

4.1 increase the application of organic fertilizer and topdressing chemical fertilizer in time

For pear trees prepared for high grafting, organic fertilizer should be applied in the autumn of last year or spring of the same year, and high quality farm manure 100~150kg should be applied to each plant to maintain the nutrient supply of high grafting trees. At the same time, topdressing should be carried out in time, and the topdressing time should be carried out after high grafting survived, according to strip ditch, ring ditch and other methods. Each mature tree should be applied pear special fertilizer (N ∶ P ∶ K is 2 ∶ 1 ∶ 1) 1~1.5kg.

4.2 foliar spraying

In order to promote the growth and ripening of new shoots of high grafted Nanguo pear, 0.3% 0.5% urea aqueous solution should be sprayed twice from June to July, and 0.3% 0.5% potassium dihydrogen phosphate aqueous solution should be sprayed twice from August to September to accelerate the growth and ripening of high grafted Nanguo pear branches.

4.3 timely irrigation

After high grafting, the high grafting tree should be watered once immediately to ensure sufficient humidity in the garden and promote wound healing. In the middle and late June, when the growth of high-grafted shoots is accelerated, it should be irrigated again according to the water demand of the high-grafted garden.

Practice has proved that more flower buds can be formed in the same year by fertilizing and irrigating the high-grafted Nanguo pear trees and strengthening the management, and a certain yield can be obtained in the second year.

5 attach importance to summer shearing and reasonable winter shearing

In order to control the excessive growth of grafted shoots, the grafted branches should be cut in summer in summer. the specific method is that when the new shoots of grafted branches grow to 40cm, they should be coring at 30cm to promote branches, expand the crown and promote early fruiting. For the branch group grafted with inner chamber, the heart should be picked in the middle and late June to promote the formation of flower bud, the branch should be pulled if the growth angle is not ideal, and the strong branch with upright growth should be ring-cut or scratched in the following spring. Winter shearing is mainly light, in line with the principle of light cutting and less thinning, the strong and strong branches with good high grafting parts are cut short at the full buds; the high grafting of the same branch can be strong, stay weak and control growth in order to promote wound healing. After that, the crown has been enlarged in the second year, and normal pruning can be carried out.

6. Prevention and control of diseases and insect pests

The bud germination after high grafting is later than the normal shoot, and the new shoot is young and tender, so it is most vulnerable to diseases and pests such as red spider and pear stem wasp, so it should be controlled in time according to the insect situation. For red spiders, Baumei 0.3 ℃ 0.5 °stone sulfur mixture or 5% nisolone 2000 × 2500 or 20% amitraz 1000 times should be sprayed during the peak stinging period of pear blooming (daily average temperature 9 min). For pear stem wasps, 50% parathion EC 1500-2000 times or 40% Lesbon EC 2500-3000 times should be sprayed around the middle of May during the peak period of adult occurrence. At the same time, before the onset of the rainy season in mid-and late June, fungicides such as 500-800 times of 50% methyl thiophanate wettable powder were sprayed once to control pear scab, so as to make the new shoots grow normally and achieve Lignification.