The latest course on grafting techniques of kiwifruit trees

Kiwifruit, also known as Yangtao, Mao Peach, Shanyang Peach, Mao Pear and so on, is an ancient wild vine fruit tree native to China. Kiwifruit was recorded as early as in the Book of songs in the pre-Qin period. China's folk artificial cultivation has a history of more than a thousand years and has a very high cultivation value. let's take a look at the grafting technology of kiwifruit trees.

Grafting time of kiwifruit trees

The suitable grafting time for kiwifruit trees is from early May to early July, and the most suitable time is from mid-May to early June. At this time, the temperature is suitable, the average temperature is 19.4-23.3 ℃, the survival rate of grafting is high, the buds germinate early, the growth period is long, the growth is large, the number of mature nodes is large, the quality of seedlings is good, and those who do not survive can be regrafted in time.

Selection of kiwifruit rootstocks

The seedlings with strong growth were selected as rootstocks and 2-3 buds were cut flat during the dormant period. If the big tree is replanted with improved varieties, it is necessary to retract the perennial branches, leave 2-3 buds short in the annual branches, and remove the overdense and weak perennial branches and annual branches, so as to reduce the number of branches and buds and promote their growth. After the rootstock sprouted in spring, the buds were wiped and the shoots were fixed. Rootstocks used to propagate grafted seedlings usually leave a new shoot. In order to replace the trees with improved varieties, a certain amount of new shoots should be selected according to the size of the tree, and the new shoots should be evenly and compactly distributed. In order to promote the thickening growth and maturation of new shoots, when the new shoots had 7-8 leaves, 5-6 leaves were left to pick the heart, and the new shoots could be grafted when they were semi-lignified.

Scion preparation of kiwifruit tree

Using the improved varieties adapted to the local environment as the spike mother tree, the new shoot of the scion should be a strong fruiting branch or developmental branch with short internodes, thick petiole and thick leaves. In order to promote the ripening of new shoots and the differentiation of lateral buds, the same coring measures as rootstock shoots were taken and collected during semi-Lignification. Using semi-lignified shoots as scions has high survival rate and early germination. It should be noted that the maturity of scion is basically the same as that of rootstock, so as to facilitate the survival of grafting. Cut off the leaves immediately after picking the new tip of the scion, leaving the petiole not more than 0.5 cm, it is best to marry and collect now. If it is not used or transported for a short time, soak the lower part of the scion in water or wrap it with a wet cloth to moisturize.

Grafting technique of kiwifruit trees

1. Split method: this method is used when the rootstock is thicker, leaving 3-4 leaves on the new tip of the rootstock and cutting it at 4-5 cm on the leaf. The new shoot of the rootstock should have appropriate amount of leaves, too few leaves, small nutritional area, poor growth after grafting, too many leaves, too long rootstock, and the fruit part of the grafted tree should be moved outward and not compact. At the same time, make sure to cut off the semi-Lignification of the new shoot as a rootstock. After the new tip of the rootstock is cut, a joint about 3 cm long is longitudinally split in the middle of the section. The scion with a single bud is cut by 4 centimeters and 5 centimeters under the bud, and an equal length cutting surface is cut on each side of the bud, about 3 centimeters long. the cutting surface is smooth and straight, and then cut at 2 centimeters above the bud. Slowly insert the chopped scion into the interface of the rootstock, exposing the cutting surface of the scion 0.1 to 0.2 cm, and the cambium on one side of the cutting side is aligned with the cambium on the side of the grafting interface of the rootstock. Bind the interface and scion tightly with an agricultural film about 1 cm wide, exposing only the petiole and bud eye of the scion, and finally wrap the interface and scion with 1 or 2 leaves in the lower part of the rootstock to protect them from the sun.

2. Cutting method: this method is used when the rootstock is thinner, leave 3-4 leaves on the new tip of the rootstock, and cut off at 4-5 cm on the bud. When opening the interface, it depends on the thickness of the scion. The incision is cut vertically at 4 points of the cross section, and the length of the incision is about 3 cm. The single-bud scion is cut at 4-5 cm under the bud. According to the size of the interface of the rootstock, the cutting surface is about 3 cm long on the opposite side under the bud, which is the same as the interface width and slightly longer than the interface. On the opposite side of the cutting surface, cut a short cutting surface about 1 cm long, and finally cut it at 2 cm on the bud. After the rootstock is joined, the upper part of the cutting surface of the scion is exposed to 0.1cm and 0.2cm, and the other treatments are the same as the splitting method.

3. Tongue grafting method: this method is used when the thickness of the rootstock is about the same as that of the scion. There are 3 leaves on the new tip of the rootstock, cut off at 4 cm on the bud, cut the Malt-shaped cutting surface of about 2 cm, and cut a cut about 1 cm long vertically at the top of the cutting surface. The single-bud scion was cut at 4-5 cm under the bud, and a cutting surface of the same size and shape as that of the rootstock was cut on the opposite side of the bud. The lower edge of the longitudinal cut of the rootstock and scion was tongue-shaped. Insert the tongue-shaped parts of the rootstock and scion into each other's incisions, and other treatments are the same as the splitting method.

4. Embedded bud grafting: hold the scion upside down when cutting the bud, cut one knife obliquely from 1.5 cm above the bud to about 1 cm under the bud, then cut diagonally at about 0.6 cm under the bud, deep to the last cut, take off the bud with xylem, the length of the bud is about 2 cm, and the thickness of the woody part is 0.2 to 0.3 cm. The interface is opened on the 45th node of the new shoot of the rootstock, and the opening method is the same as cutting the bud, and the size is the same as the bud grafting. The grafting bud is embedded in the graft interface, and the cambium is aligned. If the grafting bud is not as big as the interface, most of the cambium can be aligned. Use agricultural film to bind, fasten the interface and bud grafting, only expose the bud petiole and bud eye, and leave a leaf in the upper part of the interface to cut off the anvil tip.

5. T-shaped grafting: this method is used when the degree of Lignification of rootstock and scion is high. When cutting and grafting buds, first cut a knife to the depth of xylem at about 0.6 cm on the bud, then oblique cut deep into the xylem at about 1 cm under the bud to the cross cut on the bud, gently rub off the bud with your hands, and take the buds with shoots, otherwise it will have a great impact on the survival rate of grafting. Open a T-shaped grafting joint on the 45th section of the new shoot of the rootstock, gently peel off the interface, insert the grafting bud, so that the upper side of the grafted bud is closely connected with the upper side of the interface, and then use agricultural film strips to tie two circles under the petiole to make the bud stretch close to the rootstock, and then tie the whole bud tightly, exposing only the petiole and the bud eye.