There are several ways to graft trees (share the methods and skills of grafting big trees)

Aging varieties and extensive management are one of the main reasons for the low efficiency of many orchards. These orchards should wear new shoes, take a new road, make use of the existing plant spacing and crown, exchange high grafting for superior new varieties, strengthen the management of supporting technologies, and realize the goal of "exchanging high grafting in one year, recovering crown in two years and putting into production in three years". Let's take pear trees as an example to talk about five methods of high grafting of fruit trees, hoping to provide some help to friends!

Take a scion

Pear trees with pure varieties, strong growth, no quarantine pests and diseases and stable characters are selected as cutting mother plants. In spring, annual branches with full growth and thickness matching the rootstock should be selected as scions, and they should be collected as far as possible before germination and used as soon as possible. Scions collected during dormancy should be stored in sand or refrigerated with moisture. On the basis of the selected quantity, 20% of grafting cuttings are reserved for supplementary grafting.

Grafting time

Many years' practice has proved that the best time for high grafting in spring is from the middle and late March to the early April, taking Jincheng, Shanxi as an example. The sap flows slowly too early, and the survival rate of grafting is low, but it grows vigorously after survival; Too late, a large number of grafted trees germinate and compete with scion germination for nutrients, which leads to the decrease of grafting survival rate; From mid-March to early April, the sap flows quickly, the grafting joints heal quickly, and the scion has a high survival rate and good growth.

Selection and maintenance of high joint parts

Before high grafting, the plants to be grafted are pruned, and twigs with diameters of 1 ~ 2cm on the back of main branches and side branches are selected for high grafting (Figure 3), and redundant twigs are removed. Generally, trees with the age of 15 are selected, and 5-9 trunk branches are selected, and each trunk branch is reserved with 12 side branches for head exchange, and 50 branches are grafted at each plant height. For plants over 40 years old, each plant can be grafted with 250 ~ 300 scions, which is beneficial to the formation of new trees. When changing the first branch, leave a graft pile of more than 5 cm to prevent it from surviving. If too many grafting parts are left, it is easy to cause crowded branches, closed crown, thin branches and relatively long internode length. There are too few grafting sites left, and the crown recovery is slow (Figure 4), which affects the results of the next year (Figure 5).

Fig. 3 Selection of high engagement position

Fig. 4 crown recovery of summer scion germination

Fig. 5 results of grafted trees

High connection method

At the apex of the retracted main branch and side branch, the extension head generally adopts skin grafting or cutting; For smaller retraction branches, the method of cutting off or abdominal connection is adopted; Branchlets less than 2 cm in diameter are split; Subcutaneous abdominal transplantation was carried out with branches of 5 ~ 10 years old in the exposed part of the lumen; In the area where the bark cork is seriously bald, the method of drilling and plugging with electric drill can also be used.

0 1 skin grafting method (Figure 6)

It is suitable for the extension joint of thick main branches and side branches. Firstly, the back of the bud eye at the lower part of the scion is obliquely cut downward into a "horse-ear-shaped" flat section with a length of 2-3 cm; On the back of the long section, cut a small inclined plane with a length of 0.5 ~ 1.0 cm. On the flat side of the rootstock surface, vertically draw a seam of about 3 cm, carefully insert the scion, properly expose the upper part of the scion section, and then tie it tightly. After germination, the membrane is broken and the buds are exposed to promote the growth of grafted buds.

Fig. 6 The extension heads of main branches and lateral branches are connected 1. Cutting the scion; 2. Draw the interface cortex vertically; 3. Insert scion for binding; 4. Breaking the membrane and exposing buds; 5. Grafting buds to grow new buds

02 Cutting method (Figure 7)

Cutting grafting method is used to graft shoots with inner diameter less than 2 cm. First, leave the smooth side of the short pile with a length of 4 ~ 5 cm near the bark, and cut a 2 ~ 3 cm long incision vertically downward. Cut an inclined plane with the length of 1 ~ 2cm on one side of the scion bud under the cut to reach the xylem, and cut a short section with the length of 0.5 ~ 1cm at the opposite side of the section at a 45-degree angle, leaving 1 ~ 2cm at the upper end for cutting. Insert the scion into the incision of the rootstock with the long section facing the xylem, align the rootstock with the cambium of the scion, and wrap it tightly with a film.

Fig. 7 schematic diagram of single bud cutting method 1. Annual branch scion; 2. Cut off the side and front of the bud and one side of the rootstock; 3. bud insertion interface; 4. Plastic film tied tightly

03 Abdominal connection (Figure 8)

Use a knife to cut a long section 2 ~ 3 cm long at the lower part of the scion, and the section should be straight. Then cut a small section 0.5 ~ 1.0 cm long on the opposite side of the section to make the lower end slightly sharp, and leave 1 ~ 2 buds on the upper part of the scion. The terminal bud should be left on the back of the big section, and the section must be smooth, and cut off 0.5 cm above the terminal bud. Cut a knife obliquely downward at the grafting part of the rootstock, and the incision forms an angle of 20 ~ 30 with the rootstock, reaching the xylem 1/3 ~ 1/2. Then, quickly insert the large section of the scion into the incision inside the rootstock, align it with the cambium on one side, and tie it tightly with plastic film.

Fig. 8 schematic diagram of single bud abdominal grafting 1. Annual branch scion; 2. Cut off the back, front and side of the bud; 3. oblique cutting interface of rootstock; 4. bud insertion; 5. Plastic film tied tightly

04 Splicing method (Figure 9)

Generally suitable for thicker rootstocks. Cut the scion into two wedge-shaped facets with equal length, and the facets are 2 ~ 3cm long. Cut the rootstock at a suitable position, flatten the cross section, and chop it vertically in the middle of the cross section of the rootstock with a grafting knife. The depth is slightly longer than the cross section of the scion. Then insert the cut scion, so that the cambium on one side is aligned, the upper end of the scion section is exposed about 0.5cm, and it is tightly wrapped with plastic film strips from bottom to top to prevent air leakage, water loss and rainwater from entering.

Fig. 9 Schematic diagram of single bud division method 1. Annual branch scion; 2. Cut the side and front of the bud, and split the rootstock from the middle; Step 3 bud grafting

Entrance; 4. Plastic film tied tightly

05 subcutaneous abdominal connection (figure 10)

It is mainly used to cut branches and fill the gap in the bald part of big branches. Cut a knife obliquely on the lateral abdomen of the rootstock and cut it into a wedge-shaped surface about 3 cm long. Cut a smooth plane with slight xylem about 2 cm in the middle of the back of the scion bud, and cut a short section of about 1.5 cm at the lower end opposite to this section. The long side is thicker and the short side is slightly thinner, leaving 1 ~ 2 complete buds, and cut the upper end of the scion. Insert the cut scion into the opening of the rootstock, align it to form a layer, and tie it tightly with a film.

Figure 10 Inner Hole 1 Schematic Diagram of Bare Partial Abdominal Transplantation. Bud grafting part; 2. Cut the phloem; 3. The front end of the scion; 4. scion side; 5. Insert the scion; 6. Film binding; 7. End of hole forming; 8. Live and untie

Timely repair

/kloc-After changing the head in 0/5 days, if the bud eye is thin and the scion loses water, it can be repaired in time. In order to create favorable opportunities for replantation, the 1 graft should be carried out as soon as possible so as to have enough time for replantation. Alternatively, 1 ~ 2 shoots can be left and replanted by bud grafting, square grafting or T-bud grafting from mid-August to early September.

Management after high grafting and seed exchange

0 1 wound care

Scions that are cut, split and grafted under the skin should be coated with white latex or sealed with wax, and the wounds of big branches after crown replacement and pruning should be coated with white latex or paint to facilitate wound healing.

Wipe the bud

After germination in spring, the new buds are erased from the original branches and grafted parts, and only the grafted new buds are kept to promote the growth of the new buds. Wipe the bud sooner rather than later, usually several times.

Pick your heart

In order to promote the growth of grafting and form more branches, it is necessary to remove the heart. The time of coring is very important, and grafting too early and tender will affect its growth; It's too late, the branches after core removal are not mature enough to form flower buds, which affects the secondary yield. The best time for coring is when the grafting length is 25 ~ 35 cm. At this time, the effect is the best, and up to 6 branches can be sent out, usually 3 ~ 4 branches.

04 broken membrane

When the grafting reaches a certain length, the membrane must be broken. The rupture time is generally in the first half of June. Breaking the membrane prematurely, because of the spring drought, the interface loses water and is easy to die; If the membrane breaks too late, the interface will form a ring, which is easy to break when the wind is strong

Pull out branches and take branches.

Branching and taking branches are generally carried out in the first half of July. The method is to take branches in their respective directions, take them at an angle of 50 ~ 60 and fix them with ropes. This is an important measure to promote the formation of flower buds. Branch pulling time is very important, too early, the branch length is not enough, which is not conducive to crown expansion, and it is easy to sprout long branches on the back; Too late is not conducive to the formation of flower buds.

Spraying foliar fertilizer

In order to make the graft grow vigorously and form more flower buds, foliar fertilizer potassium dihydrogen phosphate can be sprayed 300 times, 4 ~ 5 times a year, from May to the end of August.

07 winter pruning

In the winter of grafting year, pruning should be carried out according to the characteristics of grafted varieties. For varieties that are easy to bloom, cut off long branches, keep full buds in the middle and back, and remove some dense and crossed branches; If it is not easy to bloom, it is generally to thin out the branches that are too dense, long branches, horizontal branches and upright light-blocking branches, and the remaining branches are gradually leveled. In addition, it is necessary to strengthen the management of water and fertilizer, pay attention to the prevention and control of pests and diseases, and ensure the fruit in the second year and high yield in the third year.