The Latest Grafting Techniques and Methods Tutorial for Kiwi Trees

Kiwi is also known as yangtao, maotao, shanyangtao, maolitao, etc. It is an ancient wild vine fruit tree native to China. As early as the pre-Qin period, there were records of kiwi in the "Book of Songs." The history of artificial cultivation among the people of our country reaches more than a thousand years, and it has extremely high cultivation value. Now let us take a look at kiwi tree grafting techniques!

Grafting Time for Kiwi Trees

For kiwi tree grafting, green branch grafting from early May to early July is more suitable, and mid-May to early June is the most suitable. At this time the temperature is suitable, with an average temperature of 19.4-23.3°C. The grafting survival rate is high, the grafted buds sprout early, the growth period is long, the growth amount is large, the number of mature nodes is high, and the seedling quality is good. Grafts that do not survive can be re-grafted in time.

Selection of Rootstock for Kiwi Trees

Choose vigorously growing seedlings as rootstock, and during the dormant period leave 2-3 buds and cut flat. If converting large trees to improved varieties, heavily renew the perennial branches, shorten 1-year-old branches leaving 2-3 buds, and remove excessively dense and weak perennial branches and 1-year-old branches to reduce the number of branches and buds and promote growth. After the rootstock sprouts in spring, carry out bud removal and shoot positioning. The rootstock used for propagating grafted seedlings generally retains one new shoot. For trees to be converted to improved varieties, a certain number of new shoots should be selected and retained according to tree size, and the retained new shoots should be evenly and compactly distributed. To promote thickening growth and maturity of new shoots, when the new shoot has 7-8 leaves, pinch off the tip leaving 5-6 leaves. When the new shoot matures to semi-lignified, grafting can be carried out.

Preparation of Scions for Kiwi Trees

Use improved variety plants adapted to the local environment as mother trees for collecting scions. The new shoots used as scions should be strong fruiting branches or developing branches with short internodes, thick petioles, and thick leaves. To promote new shoot maturity and lateral bud differentiation, adopt the same tip-pinching measures as for rootstock new shoots, and collect when semi-lignified. Using semi-lignified new shoots as scions gives a high survival rate and early sprouting. Note that the maturity of the scion and the maturity of the rootstock new shoot should be basically consistent to facilitate grafting survival. After collecting the scion new shoot, immediately cut off the leaves, leaving petioles no longer than 0.5 cm. It is best to graft immediately after collecting. If not used for a short time or shipped out, immerse the lower part of the scion in water or wrap it with wet cloth, etc., to keep it moist.

Grafting Techniques for Kiwi Trees

1. Cleft grafting: This method is used when the rootstock is relatively thick. The new shoot used as rootstock should retain 3-4 leaves, and be cut 4-5 cm above the leaves. The rootstock new shoot should retain an appropriate number of leaves. If too few leaves are retained, the nutritional area is small, and growth after grafting is poor. If too many leaves are retained, the rootstock is too long, and the fruiting part of the converted tree moves outward and is not compact. At the same time, ensure that the cut is made at the semi-lignified part of the new shoot for use as rootstock. After cutting the rootstock new shoot, split vertically in the middle of the cut surface to make an incision about 3 cm long. For a single-bud scion, cut 4-5 cm below the bud, cut a cut surface of equal length on both sides below the bud, about 3 cm long, smooth and straight, then cut 2 cm above the bud. Slowly insert the prepared scion into the rootstock incision, leaving 0.1-0.2 cm of the scion cut surface exposed at the top, and align the cambium on one side of the cut surface with the cambium on one side of the rootstock graft incision. Use agricultural film about 1 cm wide to tie the incision and scion tightly and securely, exposing only the scion petiole and bud eye. Finally, use 1-2 leaves from the lower part of the rootstock to wrap the incision and scion to retain moisture and protect from sunlight.

2. Cut grafting: This method is used when the rootstock is relatively thin. The new shoot used as rootstock should retain 3-4 leaves and be cut 4-5 cm above the bud. When making the incision, proceed according to the thickness of the scion. Cut vertically downward at 1/3-1/4 of the cut surface, with an incision about 3 cm long. For a single-bud scion, cut 4-5 cm below the bud. According to the size of the rootstock incision, cut a cut surface about 3 cm long on the opposite side below the bud, with the same width as the incision and slightly longer than the incision. On the opposite side of this cut surface, cut a short cut surface about 1 cm long, and finally cut 2 cm above the bud. After combining the rootstock and scion, leave 0.1-0.2 cm of the upper part of the scion's large cut surface exposed. Other handling is the same as cleft grafting.

3. Tongue grafting: This method is used when the rootstock is relatively thin and roughly the same thickness as the scion. The rootstock new shoot should retain 3-4 leaves and be cut 4-5 cm above the bud, then cut into a horse-ear-shaped cut surface about 2 cm long. At the top of the cut surface, cut vertically downward at 1/3 to make an incision about 1 cm long. For a single-bud scion, cut 4-5 cm below the bud, and cut a cut surface on the opposite side of the bud with the same size and shape as the rootstock cut surface. The lower edges of the vertical incisions on the rootstock and scion cut surfaces are tongue-shaped. Insert the tongue-shaped parts of the rootstock and scion into each other's incisions. Other handling is the same as cleft grafting.

4. Chip budding: When cutting the scion bud, hold the scion upside down, cut obliquely from about 1.5 cm above the bud down to about 1 cm below the bud, then cut obliquely at about 0.6 cm below the bud, deep enough to reach the previous cut, and remove the bud piece with xylem. The bud piece is about 2 cm long and 0.2-0.3 cm thick with xylem. Make an incision on the 4th-5th node of the rootstock new shoot in the same way as cutting the scion bud, with the same size as the bud. Insert the scion bud into the graft incision, align the cambium. If the scion bud and incision are not the same size, most of the cambium can be aligned. Use agricultural film to tie the incision and scion bud tightly and securely, exposing only the scion bud petiole and bud eye. Leave 1 leaf above the incision and cut off the rootstock shoot.

5. T-shaped budding: This method is used when the rootstock and scion have a relatively high degree of lignification. When cutting the scion bud, first make a horizontal cut about 0.6 cm above the bud deep to the xylem, then cut obliquely upward from about 1 cm below the bud deep into the xylem to the horizontal cut above the bud. Hold the scion bud with your hand and gently twist to remove the bud piece. The removed bud piece must carry the young shoot, otherwise it will greatly affect the grafting survival rate. Make a T-shaped graft incision on the 4th-5th node of the rootstock new shoot, gently peel open the incision, insert the scion bud, and make the upper edge of the scion bud closely connect with the upper edge of the incision. Then use agricultural film strips to first tie two rounds tightly below the petiole, so that the bud piece spreads out and fits closely against the rootstock, then tie the entire scion bud tightly and securely, exposing only the petiole and bud eye.