Grapes in the north need to be buried in the soil to prevent cold, so pruning in winter should be carried out after defoliation and before the soil freezes. In the south, although it takes a long time from natural defoliation to germination in the next year, pruning should be done two months before germination. If pruning is carried out in the bleeding period in spring, it will cause the loss of nutrients, and the bleeding fluid will flow down the branches and vines, which is vulnerable to pests and diseases.

2. A pruning method for fruiting mother branches

Results There are three pruning methods for mother branches:

(1) Short tip pruning

Results 1~4 buds were cut from the mother branch, of which only 1 bud or only the base bud of the mother branch was left, which was called ultra-short branch pruning.

(2) Trim the middle tip

Results 5~7 buds were cut from the mother branch.

(3) Pruning long tips

Results More than 8 buds were cut from the mother branch.

Under trellis cultivation, for most varieties with high budding intensity at the base, the mother branches are generally pruned with short branches, and hedge cultivation is mostly combined with short branches and middle branches. However, for varieties with low basal bud intensity, such as some varieties of Eurasian species, the part where flower buds are formed is slightly higher, and generally short and medium branches are mixed for pruning, while long branch pruning is mostly used for pruning local baldness of main vines and extended branches.

When short branch pruning is used for shed cultivation, the method of single branch regeneration pruning should be adopted for bearing mother branches (as shown in figure 1). That is, when pruning in winter, 2~3 new shoots on the bearing mother branch of each short branch are retracted to the lowest branch, and 2~3 buds are cut off as the bearing mother branch of the next year. The fruiting mother branch of this short branch is the fruiting unit of the second year, and it is also the regenerated branch of the second year. The fruiting and regeneration are carried out on a short branch mother branch. Cut off the upper mother branch in winter and 2~3 buds from the lower mother branch every year, so that the bearing mother branch is always close to the main vine. This kind of regeneration and pruning of fruiting mother branches has the following advantages: the fruiting parts are not easy to move out, which is beneficial to high and stable yield; The number of buds and branches is appropriate, which saves water, nutrients and the workload of wiping buds and fixing branches; The branches and vines on the shelf surface are evenly distributed, and the pruning method is simple and easy to master.

As shown in figure 1 single branch update pruning

1. Prune 2 in the current year. Prune in the second year. Prune in the third year.

When pruning medium and long branches, the mother branch is generally pruned with two branches (as shown in Figure 2). When pruning, 2-3 short branch buds are left as reserve branches on the lower branches of the two mother branches in the fruiting branch group; According to the characteristics and needs of varieties, the upper branches can be pruned for medium and long branches. When cutting in the winter of the following year, the middle and long branches bearing fruit on the upper part can be thinned together with the mother branches from the base; According to last year's pruning method, the two new branches of the lower branch are left long (medium-long branch pruning), and the lower branch is left short, leaving 2~3 buds. This cycle takes place every year. This method of regeneration of fruiting mother branches makes the fruiting parts move outward faster, with large branches, dense branches and poor ventilation and light transmission.

As shown in fig. 2, two branches are updated and pruned.

3. Update and pruning of branch groups

After several years of continuous growth, the base of the branch group gradually thickens, the incision increases, and it grows and ages in a curve shape, and the fruiting ability decreases, and the water and nutrient transport ability weakens, so it must be updated in a planned way. Branches are generally updated every 4 to 6 years. From the new shoots from the latent buds of the main vine (or the latent buds at the base of the branch group), select the new shoots with suitable position and vigorous growth to replace the old branch group and cultivate the new branch group. In order to make the new shoots grow, the old shoots should be thinned in batches and stages during cutting in winter.

4. Renewal and pruning of main vines

After many years of fruiting, the main vine will be too thick, inconvenient for cold protection, easy to split, with many wounds, weak growth potential, decreased ability to transport water and nutrients, abnormal germination of bud eyes, blindness, decreased fruiting ability and yield. Therefore, the main rattan should be gradually updated, and there are two ways to update it:

(1) local update

When the middle and lower parts of the main vine grow normally, the front part grows weak, there are many blind eyes, and the fruiting ability decreases, local renewal can be carried out, and renewal can be carried out from the weak place. When pruning in winter, select branches with strong growth potential below the weak parts, cultivate new main vines, and cut off the weak parts. This regeneration method can quickly restore the tree body and has little effect on the yield.

(2) the main vine was greatly updated

Generally, the main rattan will age after 10 years and need to be updated. The method is to cultivate sprouts from the base of the old vine as regeneration vines, and gradually thinning the branches and mother branches on the old vine during pruning in winter to reduce the amount of branches on the old vine and make room for the main vine to extend forward. When the fruit yield of the regenerated vines approaches or exceeds that of the old vines after continuous cultivation for about 2 years, the old vines are thinned from the base and replaced by the regenerated vines. Large-scale regeneration must be carried out in a planned way on the premise of ensuring yield and fruit quality, and there is no rush to achieve success.

5. Pattern pruning of trellis grapes

Grape production in the north is mainly based on scaffolding, using trunk trees. Results Branches, mother branches and new shoots are regularly distributed on the main vine, so the pruning method can be modeled as 1-3-6-9~ 12. That is to say, within the range of main vine length per 1m, three fruiting branch groups are selected, and each fruiting branch group keeps two fruiting mother branches and * * * six fruiting mother branches. In winter, each bearing mother branch adopts single branch regeneration and short shoot pruning, and 2~3 buds are cut. After spring germination, select 12 new shoots from each parent branch and 9~ 12 new shoots from * * *. In this way, when the grape spacing is 1m and the grape spacing is 0.5m, there can be 18~24 new shoots per square meter, and then some new shoots can be removed by bud wiping and branch fixing, so as to achieve a reasonable amount of branches left.

According to this model, when the hedge frame is fan-shaped, four fruiting branches can be left on the main vine of1m. Moreover, the renewal cycle of main vines is shorter than that of scaffolding, and it is renewed once every 2~3 years.

6. Precautions for winter scissors

Grape branches and vines are loose and easy to lose water, and they often dry up after being cut. In order to protect the cut buds, it is necessary to leave 3~5cm branches on the cut buds to prevent them from drying up. During the shaping of young trees and the renewal of main vines, pruning should start from the main branches to avoid unnecessary losses; When pruning, it is necessary to avoid too many and too dense wounds, otherwise the tree will recover slowly and be prone to diseases and insect pests, which will affect the transportation of water and nutrients.