What are the technical essentials of grafting?

Grafting methods include root grafting, branch grafting (including split grafting and cut grafting) and bud grafting (including T-bud grafting and wood bud grafting). The following briefly introduces several methods:

(1) subcutaneous transplantation. Mostly used for relatively thick rootstocks (3 ~ 5 years old, the base diameter is better than 0.8 ~ 2 cm). The scion can adopt the first branch of an annual jujube tree or the second branch of a 2-3-year-old jujube tree with 2-3 jujube strands, the splicing length is about 15 cm, and the upper end is cut flat at a position 0.5 cm away from the fruiting mother branch or bud. The lower end is cut from the lower part of the back of the fruiting mother branch or positive bud to a slope of about 3 cm. Its reverse side is cut off to form a small inclined plane; Cut off the rootstock, choose the smooth side of the bark, cut the cortex vertically to the xylem with a knife, about 3 cm long, then peel off the rootstock incision and insert it. To align the cambium of the scion with the cambium of the rootstock, the tip of the scion is facing the kerf, and the finger is pressed against the kerf of the rootstock and slowly inserted. The cutting surface of the scion is slightly exposed from the joint, and the cutting surface of the joint and the rootstock are tightly wrapped with plastic film tape with a width of about 3.3 cm (1 inch), or the low joint can be covered with buried soil, and the high joint can be covered with plastic film.

(2) splicing. This method can be applied regardless of the thickness of the rootstock, but the large rootstock with the diameter of 1.5 cm is better. Only one scion is used for fine rootstock, and 2 ~ 4 scions can be used for coarse rootstock. Cut the truncated rootstock vertically from the center, and the thick rootstock can be cut horizontally. The length and cutting method of the scion are basically the same as that of subcutaneous grafting, but the two sides of the lower end are cut into 3 cm long inclined planes. The slope of thin scion should be short, and the section of thick scion can be slightly longer. Then insert it into the incision of the rootstock. If the rootstock is thick, it must be inserted into the tight knot side of the scion to make the cambium of the rootstock closely connected. When the roots are thin, they need to be tied, and finally they can be covered with plastic bags or buried in the soil.

Splitting method can also be used for high grafting varieties. When high grafting, the branch diameter should be about 2 cm, and pay attention to the arrangement of tree shape and backbone branches. The joint should be tightly wrapped with plastic film, and the exposed scion branches and incisions should be coated with liquid wax.

(3) Tongue joint. This method is often used for indoor grafting of grapes, and is suitable for rootstocks and spikes with the same thickness. Cut the rootstock about 8 cm, use a knife to cut the upper end of the rootstock and the lower end of the scion into horse's ear slopes with the same size and about 3 cm in length, cut a knife on the newly cut slope at the position 1/3 from the tip, and cut a knife almost parallel to the cutting plane, separate the two slopes into tongues, then embed them with each other, and then bind them with hemp skin and plastic tape.

Among the above three methods, the rootstock can also be dug up in the winter slack season, grafted indoors, stored in sand, and planted in the nursery in spring after the joint is partially healed at a suitable temperature.

(4) bud grafting. Bud grafting saves labor and scion, but it can't be done until the tree is stripped. The budding time of jujube trees is in late June, when the jujube head is extended by 30 ~ 50 cm, that is, when the developing branches have just taken out the secondary branches. Bud grafting should choose three buds on the current jujube head; Bud grafting can be divided into two types: woodless bud grafting and wooded bud grafting. Woodless budding: used for rootstocks above 0.9 ~ 1.2 cm. When cutting buds: cut off the jujube heads, select firm and full main buds, cross-cut one knife above the main buds, then cut the main buds in parallel from bottom to top at the position of 1.2 ~ 1.5cm below the main buds, slightly cut the xylem, peel off the buds, and then select smooth ones at the position of 5 ~ 10cm from the ground. Insert the bud into the D-shaped mouth, make the grafted bud stick to the xylem of the rootstock, align the top end, wrap the two sides, tie the incision tightly with hemp rope or plastic tape to expose the bud, and then cut off the top end of the rootstock at the height of 1 cm from the grafting position. Bud grafting with xylem: cut off the main buds with a small amount of xylem, cut off the main buds on the first and second branches, and then carry out bud grafting. After binding, cut the Toona sinensis with pruning shears.

(5) Single bud grafting. It combines the advantages of skin grafting and bud grafting, and avoids the shortcomings of troublesome and laborious splitting operation, difficulty in taking buds due to thick rootstock and T-bud grafting, and difficulty in binding buds, thus greatly improving the survival rate and speed of grafting. The specific operation technique is as follows: firstly, make a T-shaped incision at the distance of the rootstock from the ground 1.5 cm, then select semi-lignified or lignified jujube heads, cut them into 3 cm long as scions (about 0.5cm above the secondary branches and 2 cm below the secondary branches), and cut them into duckbill shapes (with a layer of old bark left in the middle and a trapezoidal cross section of the scion). Finally,

When using wild Zizyphus jujuba as rootstock, the grafting position should be slightly lower to keep the scion moist and prevent the wind from lodging.