Castanea mollissima seedling is an important chemical raw material, and also an excellent economic and protective forest tree species. Since it is an economic tree species, efficient productivity is the most important. So, how to improve the production efficiency of chestnut? The answer is grafting. Using grafting method to propagate seedlings can greatly improve production efficiency and increase economic benefits. Let's take a look at how chestnut seedlings are grafted~
The common grafting methods of chestnut seedlings are cutting grafting, abdominal grafting, splitting grafting and skin grafting.
1、 Cutting connection;
Cutting is usually carried out in spring. The technique is simple and the survival rate is high, but the grafted seedlings are easy to be broken by the wind in the early stage, so it is not suitable to untie the grafted seedlings too early, and the props should be set up properly to remedy the problem. After selecting the first plump and strong bud, first cut a knife from 1.5-2 cm below the bud to make the incision a 45 ° oblique section, and then turn the scion over. From the opposite side or side of the bud point about 0.3 cm away from the bud, cut forward to the xylem, and the peeled epidermis does not contain wood or slightly woody, but reaches the cambium. It is required that the long face should be smooth and not fluff. Finally, the scion was cut off at an angle of 45 ° about 0.3 cm above the bud point to form a bud. The length of the whole bud is 1.5-2 cm. Take care not to pollute sediment and other impurities after cutting the buds. Then cut off the rootstock 10-15 cm above the ground. When cutting the rootstock, we should avoid tearing the rootstock, and try to reduce the skin damage near the shear. After the cut is flattened, cut vertically from the xylem to the phloem on the straight side of the cross-section. It should be smooth and about 2 cm long, so as to reach the xylem without cutting out the xylem or the micro xylem. Then, the grafting bud with the size similar to that of the rootstock and suitable in length is inserted into the cutting of the rootstock. The long cutting face of the grafting bud is inward, and the cambium of the rootstock should be aligned with each other. If the size of rootstock and scion is not consistent, it is appropriate to align one side of cambium Between Rootstock and scion. In order to facilitate the healing between rootstock and scion, buds must be inserted vertically to the bottom of the cutting surface of Rootstock to make the base of grafting buds close to the bottom of rootstock incision. Thin film or thin film should be used to bind the eyes.
Grafting and cutting of Chestnut
Note: when cutting stock and scion, the knife should be smooth and sharp, the cutting operation should be stable and fast, the cutting surface should be flat, straight, smooth and without hair, and the cutting depth should be appropriate. The cutting surface of rootstock and scion should be kept clean and free from sediment and other impurities. When inserting scion, the operation should be light, and the tissue should not be damaged. The position of cambium of both sides should be clear. The cambium of both sides should be consistent and aligned with each other. The contact surface should be firmly combined. If viewed from the side, if there is a gap between the two cutting surfaces, it means that the cutting of the rootstock or scion is not smooth and needs to be re cut. The binding should be tight and the force should be even to make the whole joint surface close to each other. During the operation, the scion should not be moved to avoid the deviation of the aligned cambium.
2、 Abdominal connection;
Abdominal grafting is a kind of grafting method in which scion is connected to the stem or branch of rootstock without cutting off the crown of stock. Because the abdominal grafting method does not need to cut off the rootstock, it has strong healing ability, high survival rate and long grafting suitable time. It can be grafted not only in spring dormancy period, but also in summer and autumn tree growth period. The length of the rootstock is about 3.5 cm, with a little xylem. The cutting position of rootstock should be 6-8 cm above the ground for grafting in the next spring. Then cut the ear into two full buds, 7-8 cm long, and cut off the lower part of the ear. The first cut is to cut a 3.5 cm long long surface at the lower part of the cut bud, which should be straight, smooth and deep to the xylem. The second knife cuts a horse shaped inclined plane on the back of the long cutting surface and forms an angle of 40 ° with the long cutting surface. The third knife, in the upper part of the horse ear shaped slope, cuts a short cut surface on the front and back of the long plane, about 3cm long. It also requires that it be straight and smooth, reaching to the xylem, and the long and short planes are parallel. Then, the scion is inserted into the open rootstock interface, and the long cutting face is inward and the scion cambium is aligned. Finally, the scion should be bound with 1-1.5cm wide plastic tape, and then a rectangular cover (the scion should be completely wrapped with plastic tape without covering for single bud), and the top and bottom should be tightly bound with plastic belt.
Chestnut grafting abdominal grafting
3、 Cleavage;
This method is often used when the rootstock is large and the scion is not peeled off. Cut off the rootstock at the grafting site, level the sawn surface, and make a vertical split in the middle of the rootstock with a chopper, with a depth of 6cm. If the rootstock surface is too thick, it can be split at 2-3 places around the rootstock surface, so as to cut more scions. Cut the lower end of scion into a long wedge of about 5cm, and the cutting position is changed from steep to straight, so that the scion can be clamped at the cutting position of the stock surface, and the gap is not too large. When cutting, first use an iron cutting to pry the split and insert the scion, and make the cambium of the two coincide with each other. After transplanting, there is 0.3 cm dew white on the top of the cut surface to facilitate the healing of both sides. When binding, first seal the anvil surface with a small piece of plastic film and round film, and then slit and cross seal the scion and bind tightly.
Grafting of chestnut seedlings -- splitting method
4、 Skin grafting;
When grafting, the cuticle of rootstock has been peeled, but the cortex of scion cannot be separated. Cut a 5 cm long ear shaped inclined plane at the lower end of the scion, insert the knife until 1 / 2 of the xylem, and then cut it straight forward, and then cut one knife on both sides of the back of the ear shaped inclined plane at the end, so as to reach the cambium. Cut at the grafting site of the rootstock, level the cutting edge, select the top of the smooth side of the cortex, cut the circumferential cortex vertically with a knife, and gently lift the cortex to the left and right sides at the gap with the knife edge, and insert the scion.
If the rootstock is too large and the scion is too thick to be inserted, it can be gently knocked down at the upper end of the scion, and the appropriate depth is to leave the exposed white, so that the end of the cuttings is closely connected with the cortex and xylem, and the damaged surface on the outside of the cuttings can also heal with the inner side of the bark layer of the rootstock, so the survival rate is higher. If the rootstock is large, 3-4 scions can be inserted. The binding method is the same as the splitting method. When carving a knife vertically, pay attention to cut off the cortex, do not seriously injure the xylem.
Management after grafting: after grafting, the sprouts on the rootstock should be removed in time and many times to avoid dispersing nutrients and affecting the healing and survival. When the grafting survived and healed firmly, the bound film belt should be removed in time, and fertilizer and water management and pest control should be strengthened. When the seedling grows to about 50 cm in height, it will be pinched to promote branches. The strong branches of strong seedlings may have flower spikes, which should be removed as soon as possible.