Navel orange seedlings are mainly propagated by grafting technology. To cultivate, the following work must be done. (1) The scions prepared for grafting should be collected from strong navel orange plants that have been identified as virus-free, pure varieties, and have high and stable yields. The picking parts are the one-year lignified (mature) spring shoots, autumn shoots or summer shoots in the middle, upper and outer parts of the crown. Weak branches that droop and grow inside are not suitable as scions. The scion has a high survival rate when picked and used. Only when there is no ear picking nursery or when varieties are introduced, the scions will be stored for later use. There are two storage methods for scion: sand storage and low temperature storage. For sand storage, use clean river sand with a moisture content of 5% to 10%. Put 100 scions in bundles into the sand, fill each bundle with moist river sand, then cover the surface with plastic film to keep it moisturized, and check every 7 to 10 days. And adjust the river sand humidity once.

You can also put the scion into a slightly moist, cleaned moss, use a film to moisturize it and leave stomata, and remove the fallen petioles and deteriorated scions in 3 to 5 days. If there is temperature control equipment, it can be stored in it. It can be stored for about 2 months at a temperature of 4~7℃. (2) Preparation of grafting tools Grafting tools include grafting knives, branch shears, whetstones and grafting films. The bandaging film strips used for abdominal grafting in autumn are about 0.8 centimeters wide and 15 to 17 centimeters long. 1 kilogram of film can cut 3,400 to 3,800 strips. The film used for wrapping spring cuttings is a 4 cm x 10 cm long square, used to wrap the top of the stock.

(3) Grafting method There are two methods of grafting navel orange, abdominal grafting and incision grafting. The scion must be cut off first. Scion cutting: Commonly used grafting buds include single buds and spore pieces. ① Cutting off single-bud scions: Single buds refer to scions with one bud on a 1-1.2 cm branch. Single buds can be used for ventral grafting or incision grafting. How to cut off a single bud: Hold the scion upside down with your left hand, put the broad and flat side of the bud close to your index finger, cut off the scion (short cut surface) at a 45° angle 1-1.2 cm below the bud eye, then turn the branch over, Above the broad plane bud, hold the blade close to the scion and cut off the cortex with one cut, revealing the yellow-white cambium layer (long shaved surface).

The long chamfered surface should be smooth and straight, just reaching the cambium layer. Finally, cut off the scion 0.2 cm above the bud at a 45-degree angle and place it in clean water for later use (should not exceed 4 hours). To cut off a single bud, you can also use the method of holding the branch along the branch. Cut the knife from 1 to 1.2 cm below the bud at the top of the branch toward the top of the branch. Cut off the lower cortex from deep to shallow, and cut off 1 to 1.2 cm below the eye of the branch. branch. Regardless of whether it is upright or backward, it should be straight. ② Cutting off the spores of the scion: Hold the branch with your left hand, place the last 1/3 of the grafting knife between the petiole and the bud on the outside of the bud eye (it can also be placed on the outside of the petiole), and follow the leaf mark toward the petiole at an angle of 20° Make a diagonal cut at the base, reaching deep into the xylem.

Then cut the knife 0.2 cm above the bud eye, and cut toward the base of the branch in a direction parallel to the branch. When it intersects with the first incision, use your thumb to press the peeled buds on the blade, remove the buds, put them into water and set aside. The buds are 0.7~1.0cm long, 0.3cm wide, and have a little The xylem has a wedge-shaped base, and the bud bracts can be used for ventral grafting or incision grafting. (4) Abdominal grafting method and grafting period Abdominal grafting method is widely used. The scion can be either a single bud or a bud bract. Those with single buds are called single bud ventral contact, those with bud bracts are called bud bracts or T-shaped exposed buds.

The operation method of abdominal grafting is as follows: ① Stock incision: The incision is 10 to 15 cm away from the ground, and the smooth side in the southeast direction is selected for the incision. The incision shape is II or T-shaped or inverted T-shaped. The operation method of the inverted T-shaped incision is to place the front 1/3 of the blade close to the trunk of the stock, push down and cut longitudinally, cut the bark of the stock from shallow to deep, the length of the cut is slightly longer than the scion, and cut off 1/3 of the peeled cortex. ~1/2, to prevent the cut skin of the rootstock from covering the bud eye of the scion. The cortex of the scion should be aligned with the cortex of the incision, and the lower end of the short cut surface of the scion should be in contact with the bottom of the incision of the stock. Wrap the scion and stock tightly with film tape. During abdominal grafting in spring or May to June, the buds can be bandaged.

To cut the inverted T-shaped rootstock incision, you should choose the smooth and straight side of the rootstock, make a cut from top to bottom to form an inverted T shape, and insert the grafting bud into the inverted T from bottom to top. into the shaped opening, and then wrap it tightly with a film strip. ②Grafting period: When grafting in the open field, except when the temperature is below 12℃ or above 37℃, the grafting survival rate is low, grafting can be done at other times. Seedlings can be grown in protected areas and can be grafted all year round, but the best effect is when the temperature is between 20 and 30°C. The interface heals fastest when the temperature is around 25°C. (5) In the cutting method and during the grafting period, single buds or bud bracts can be used to cut the scions. Those using single buds are called single bud incisions, and those using bud bracts are called single bract incisions.

In areas with abundant rainfall, 1 to 2 days before grafting, cut the rootstock 15 cm from the ground to allow the excess water to evaporate to prevent excessive moisture at the joints, which may cause the incision to become moldy. ① Rootstock incision: At a distance of 10 to 15 cm from the ground, choose the smooth side in the southeast direction and cut everything longitudinally, with the incision reaching the cambium. At the upper part of the rootstock incision, use a grafting knife to cut off the rootstock diagonally inwards. The cross section of the nitre wood should be smooth to facilitate healing. The rootstock incision is on the side with the lower section, and the length of the incision is related to the scion: if the scion uses a single bud, the incision should be shorter than the scion. After the scion is placed in the incision, the buds should expose the rootstock incision; if the scion uses bud bracts, the rootstock incision should be the same as the bud. Equally long, and cut off 1/3~1/2 of the cortex at the incision of the rootstock to prevent the cortex from covering the bud eyes.

If the grafted rootstock is thick and difficult to cut with a grafting knife, you can use branch scissors to cut off the rootstock first, and then make an incision. Use a knife to trim the rootstock section smoothly, and keep the rootstock incision on the lower side of the rootstock section. When the scion is placed into the incision, the lower end of the short shaved surface of the scion should be in contact with the bottom of the incision, the cortex and cambium of the scion should be aligned with each other, and then the interface should be wrapped. Wrap the interface with a 20 cm long film strip. When bandaging, tie one end of the strip 1 to 2 times in the middle of the interface, then fold the upper end of the film to the opposite side and tie it into the strip so that a film "chamber" is formed in the upper part of the interface. Cover it to keep warm and moisturize, and improve the survival rate.

When the buds sprout 3 to 5 leaves, cut off the top of the "cell" to avoid hindering the growth of the scion. In navel orange production areas where the temperature is rising steadily, exposed buds can be bandaged, but only the small holes at the eyes of the buds will be left, otherwise the survival rate will be reduced. ②Grafting period: Usually grafting is in spring. In the south subtropical navel orange producing areas where the temperature rises steadily in spring, the survival rate of cut grafting is high in spring; while in the central subtropical navel orange producing areas, the survival rate is unstable due to the influence of temperature.