Key Points and Detailed Operation Methods of Citrus Grafting Techniques

Citrus is a very common fruit in our daily life, and regular consumption also has dietary therapeutic effects in preventing cancer. It is rich in nutrients, so it is deeply sought after by people. As we all know, citrus is a fruit that can be grafted, and after grafting, some of its undesirable varieties are improved, and its advantages are still very strong.

Citrus Grafting Techniques

Generally, autumn grafting is done in September to October, using the exposed-bud side veneer grafting method. First, at a smooth spot about 10-15 cm above the ground on the rootstock, hold the grafting knife tightly against the main trunk of the rootstock and push downward vertically from top to bottom to make a cut, with the cut going from shallow to deep and slightly into the xylem. The cut should be about 2.5 cm long, slightly longer than the bud piece, and 1/2 of the rootstock bark should be cut away. Open one row of rootstocks at a time, then cut the bud piece. Cutting the bud piece: hold the scion with the left hand in the forward direction, use the grafting knife to make a flat downward cut from 1/3 above the bud toward the front of the bud at 15°~20°, with the bud piece about 2 cm long and slightly into the xylem. Then make a 45° slanting cut at 2/3 below the bud, crossing with the first cut to remove the bud piece, so that the base of the bud piece is wedge-shaped. Insert the bud piece into the bottom of the cut on the rootstock, align the cambium on both sides, and wrap the bud piece with a plastic film strip 20 cm long and 1 cm wide, exposing the bud eye. Be careful to press firmly and wrap each round well, leaving no gaps.

Preparation Before Grafting

Bud grafting is generally carried out in autumn from September to October. The preparation of scions is mainly for autumn grafting. The mother tree providing scions should be propagated from excellent single plants with pure variety, high yield, stable yield, high quality, vigorous growth, and no quarantine pests or diseases. In the scion orchard, in early July, apply 2.5 kg of decomposed cake fertilizer + 0.25 kg of compound fertilizer per plant. In mid-July, shorten the vigorous shoots, single-terminal fruit-bearing shoots, broom shoots, flower-and-fruit-dropped shoots, and spring-tip vegetative shoots, etc., and according to the strength of the base branch, select and retain 1-3 new shoots. Strengthen the control of leafminer and anthracnose, cultivate strong autumn shoots, so as to help improve the grafting survival rate and sprouting rate, and make the grafted buds sprout strongly and vigorously.

Benefits of Citrus Grafting

1. Maintain the excellent traits of the variety. Offspring propagated by grafting can generally maintain the inherent traits of the parent, except for mutations.

2. It can propagate seedless or few-seeded superior citrus varieties. Such as Satsuma mandarin, navel orange, etc.

3. It can bear fruit earlier and achieve high yield earlier. Grafted citrus seedlings generally begin to bear fruit 3-4 years after grafting, while seedling citrus trees often need 8.10 years to begin bearing fruit.

4. Repair and rescue diseased and injured trees. Due to damage to the root crown or trunk gumming caused by foot rot, longhorn beetles and other pests, mechanical injury, etc., approach grafting can be used to replace the rootstock, and bridge grafting can be used to repair the damaged part of the trunk, so that the tree can recover its health.

5. Grafting can be used for top grafting to change varieties. Poor varieties, low-yielding individual plants, or seedling trees and other plants that do not meet requirements can be changed by top grafting into the needed varieties. Different varieties can also be grafted onto one tree to centrally preserve germplasm. Top grafting can also be used to graft hybrid seedlings onto the canopy of mature trees for earlier fruiting and identification, shortening the period of hybrid breeding.

How to Improve the Survival Rate of Citrus Grafting

1. Choose sunny weather for grafting. Before grafting, pay close attention to the weather forecast, grasp the weather trend, and combine this with observing local weather changes. If there is continuous rain, soil that is too wet after rain, fog and low temperature, or continuous sunny high temperature, grafting is not suitable. If drought occurs during grafting, irrigate thoroughly once 2-3 days in advance. Weak seedlings should be fertilized half a month in advance to improve the nutritional level of the seedlings, which is beneficial to grafting survival. However, after grafting, it should not be irrigated, and chemical fertilizers should certainly not be applied.

2. Keep the scions fresh. Scions are best collected locally and grafted immediately after collection. This is because scions collected and grafted immediately are fresh, more nutritious, and highly viable, with a high survival rate. If scions need to be purchased from elsewhere, those that cannot be used up immediately can be stored in layers with moist clean river sand or sphagnum. The humidity of river sand is appropriate when, after inserting a hand into the sand and pulling it out, sand sticks to the hand but not to the fingernails. If no sand sticks to the hand, it is too dry; if sand sticks to the fingernails, it is too wet. The humidity of sphagnum is appropriate when it does not drip.

3. Master the basic grafting skills. Grafting includes the full set of techniques such as sharpening the knife, cutting the bud, opening the rootstock, inserting the bud, and tying. Each step is directly related to the success or failure of grafting and must be strictly controlled, requiring "flat, accurate, tight, and strict," which means the rootstock and scion are cut flat, the cambium is aligned accurately, the film is sealed tightly, and the tying is tight. The better the basic grafting skills and the more skilled the technique, the higher the grafting survival rate.

When grafting citrus, it is essential to wrap it well, with no gaps left between, as this will increase its survival rate. Autumn each year is a good time for grafting, and those who need it can choose to do it during this period. However, grafting also has certain effects, and it requires an additional year of cultivation time.