Advantages and disadvantages and technical measures of square bud grafting of walnut in Xianyang City

Advantages and disadvantages and technical measures of square bud grafting of walnut in Xianyang City

The planting area of walnut in Xianyang City is 512000hm2, the preserved area is 304000hm2, and the preservation rate is 60%. The survival rate and preservation rate are low, and the varieties are cluttered and the quality is poor. The transformation of low-yield and low-efficiency forest has become an important measure to improve the quality and efficiency of local walnut industry. Starting from the varieties, the goal of high quality and high yield can be achieved through square bud grafting technology and timely management after grafting.

1 advantage

1.1 Saving panicle strips

The collection of square bud grafting scion is more convenient, 5 or 6 buds are generally retained on a spike, but a complete scion must be used for branch grafting, and square bud grafting saves panicle strips more.

1.2 High survival rate

The biggest factors affecting the survival rate of walnut grafting are air temperature and Rain Water. Generally choose grafting before the rainy season from mid-May to late June, when the temperature and humidity are suitable, and can avoid the rainy season, the survival rate can reach more than 95%.

1.3 Save labor and time

It only takes about 40 seconds for skilled grafters to take buds from ear strips to rootstocks and wrap them up.

2 inferior position

2.1 High temperature requirements

The temperature of square bud grafting is very high, and the air temperature is too low, which is not conducive to the healing of the marriage interface, and it is easy to mildew for a long time; if the temperature is too high, it burns buds and burns buds seriously, which affects the survival rate of grafting [Jishan Huayao].

2.2 ear strips cannot be preserved for a long time

The scion should be grafted with picking, otherwise the moisture of the panicle should be kept so as to prevent the survival rate of grafting from being affected by water loss. The longest preservation time is no more than 3 days.

3 Technical measures

3.1 selection of ear-picking mother tree

The excellent varieties and plants with strong growth and no diseases and insect pests should be selected for the mother tree, and the marks should be made in time after selection. The panicle strips used for square bud grafting should be the same year's developed branches with a high degree of Lignification, and the buds picked should be mature and full.

3.2 selection of varieties

In recent years, the main varieties popularized in Xianyang City are Xiangling and Luguang selected by Shandong Walnut Research Institute, Shanhe 2 and Shaanhe 5 selected by Shaanxi Walnut Research Institute, Liaohe 1, Liaohe 3 and Liaohe 4 selected by Liaoning Economic Forestry Research Institute, and Xilin 2 and Xilin 3 selected by Northwest Forestry College.

3.3 Collection, preservation and transportation of panicle strips

3.3.1 Collection. The collection time is generally from mid-May to late June. After harvesting in the early morning, the compound leaves were cut (the petiole was 2-3 cm long), and the panicles were grafted with picking as far as possible to prevent water loss and affect the survival rate of grafting.

The newly developed branches of the year with high degree of Lignification and full bud maturity were selected. After cutting off the scion, remove the compound leaves, keep 5-6 buds for each scion branch, each 20 or 30 into a bundle, mark the variety, put it in a cool place and set aside. Prevent the petiole from scratching the tender epidermis when bundling.

3.3.2 Preservation and transport. The collected scions were stored for no more than 3 days. Before grafting, the top of the scion was transected and bundled and soaked in walnut special growth regulator solution with a soaking depth of 5 cm. It can be used when water film appeared on the upper section of the scion. Transport scion, if the distance is near, it can be wrapped in wet linen cloth and transported quickly; if the road is long, it should be wrapped with plastic film, pay attention to ventilation, and when it is transported to the ground, the film should be opened in time and placed in a damp and cool place.

3.4 rootstock selection

One is low-yield forest. The seedlings in low-yield walnut forest, seedlings survived from rootstocks, low-quality trees and iron walnut and cotton walnut mixed in walnut forest were selected for comprehensive low-yield transformation. The second is the seedlings. The seedlings with long age, uncertain varieties and low yield were grafted. Third, nursery seedlings. The seedlings in the nursery with 2-year-old roots and 1-year-old seedlings with strong growth and no diseases and insect pests were selected for grafting.

3.5 grafting

Square bud grafting must be carried out in the growing period, and rootstocks are required to be one-to two-year-old branches or new shoots of the same year. When grafting, the cut of the rootstock is required to be the same size as the square bud. One is to sprout. Cut around the buds with a square knife to detach the skin from the branch. Pry up the cortex at the interface with a blade and remove the bud piece [4]. The second is the opening of the rootstock. In the smooth, semi-lignified part of the current year's seedlings, take out the same size rootstock cortex with the same square knife, and then put the buds into the interface. The third is bandaging. Tie the buds tightly with a special plastic strip to ensure that the buds are in close contact with the rootstock to avoid running wind.

3.6 Management after grafting

One is watering. The seedlings grafted in the field should be watered in time after grafting to ensure the growth of walnut seedlings. The second is cutting anvil. Budding seedlings generally need a haircut in order to promote healing. Leave 2 compound leaf cutting stocks from the top of the marriage boundary. The third is to wipe the sprout. Timely erase the seedling buds from the rootstock in order to maintain sufficient water and nutrients for scion germination and growth and improve the survival rate of grafting. Fourth, weeding. Remove weeds and crop seedlings within 1.5 m around the trunk in time to facilitate seedling growth and reduce the breeding of diseases and insect pests, and be careful not to break the seedlings on the scion. Fifth, fertilizing.

When the grafted buds grew to 30 cm, phosphorus and magnesium essence, phosphorus and potassium essence or sodium humate were sprayed on the leaves every 10 days or so. Phosphorus and potassium fertilizer should be properly increased in autumn to prevent the seedlings from overgrowing. The sixth is to untie. When the buds grow to 15: 20 cm (when the buds heal), use a knife to remove the film on the opposite side of the buds.

3.7 Disease and pest control

On the basis of full investigation, it is determined that the common diseases of walnut in Xianyang area are anthracnose, black spot, rot and brown spot, and insect pests are raised limb moth, cloud spot longicorn beetle, yellow diamondback moth, aromatic bark moth and so on. In the prevention and control of diseases and insect pests, we should fully implement the plant protection policy of "prevention first and comprehensive control", give priority to agricultural control and ecological control measures, give full play to the natural control role of natural enemies, and adopt artificial and physical methods for prevention and control. In addition, chemical control should choose chemical pesticides with low toxicity, high efficiency and low residue.