How to graft camellia with Camellia oleifera rootstock? Technology of high grafting camellia with Camellia oleifera rootstock

How does the camellia oleifera rootstock graft camellia? Technology of High Grafting of Camellia oleifera Rootstock

How does the camellia oleifera rootstock graft camellia? Camellia is a camellia plant of Theaceae, evergreen shrub or small arbor. It is one of the ten traditional famous flowers in China. It has the beauty of peony and the wind of plum blossom. It is suitable for both family potted plants and garden greening. It has extremely high ornamental value and is the five golden flowers mainly developed in Macheng City.(rhododendron, chrysanthemum, camellia, rose, apricot flower), Camellia oleifera has a long cultivation history in Macheng City, and the cultivation area is relatively large; because some Camellia oleifera trees in Macheng City belong to small old trees with very low seed setting, these low-yield Camellia oleifera trees can be utilized as rootstock grafting camellia, and the camellia cultivated in this way has large individual size, long life span and high ornamental value. Grafting is an important method to enlarge and speed up the propagation of camellia. Grafting camellia oleifera as rootstock can not only preserve the original excellent characteristics, but also improve the adaptability of camellia to the environment, and at the same time can improve the growth amount of camellia, blossom ahead of time, and prolong the viewing time of camellia. Camellia high-grafting technology in the second year of grafting can form a good crown, so that the grafted seedlings than seedlings and cuttings grow faster, greatly improve the growth rate of Camellia. This grafting technique has been widely adopted in Wunaoshan National Forest Park in Macheng City. After grafting on Camellia oleifera trees in Macheng City, more than 600 Camellia varieties have been cultivated. Camellia cultivation in Macheng City has a history of more than 1600 years.

Test site: Wunaoshan Forest Farm in Macheng City, also known as Wunaoshan National Forest Park in Macheng City, is located in the northeast of Hubei Province, the southern foot of the middle Dabie Mountain, and the junction of Hubei, Henan and Anhui provinces. It is located at 30°52 '~31°36' N and 114°40 '~115°28' E. Altitude ranges from 25 to 1 337 m. A subtropical continental monsoon climate, with sufficient light, mild climate, abundant rain, rain and heat in the same season, four distinct seasons characteristics. The annual average rainfall is 1 223.7 mm, the maximum rainfall in wet year is 2 009.0 m(1954), and the minimum rainfall in dry year is 683 mm(1978). The annual distribution is uneven, and the flood season is from May to September. The annual average temperature is 16 ° C. The highest extreme temperature was 41.5 ° C (1959) and the lowest was-15.3 ° C (January 1977). The annual sunshine hours were 2 036 7 ~2 153 1 h, and the sunshine percentage was 46%~49%. The total energy of light radiation is 108.2~113.3 ka/cm2. Frost-free period 228 days. The soil includes yellow brown earth, fluvo-aquic soil and paddy soil. The pH value of the soil ranges from 5.60 to 6.68. The organic content of the soil ranges from 0.6% to 2.5%, the total nitrogen content ranges from 0.5% to 0.2%, the alkali-hydrolyzable nitrogen content ranges from 30 to 15 ppm, and the available potassium content ranges from 30 to 200 ppm.

1 Preparation before grafting

1.1 Rootstock preparation

(1)Selection and transplantation of low yielding camellia oleifera trees. The transformation of Camellia oleifera with low yield can not only reuse resources, but also greatly shorten the time of cultivating rootstocks. In the existing low-yield Camellia oleifera forest, select a Camellia oleifera tree with an age of 30 - 50 years, a ground diameter of 5 - 10 cm, strong growth and no pests as a rootstock (Figure 1).

(2)Pruning of rootstock before grafting. 1~2 months before grafting, the long branches, dead branches, weak branches, diseased branches and overlapping branches of the rootstock are cut off, so as to facilitate ventilation and illumination, reduce the occurrence of diseases and insect pests, avoid useless nutrient consumption, make the plant grow healthy and ensure the vigorous growth of the rootstock. Before grafting, the trunk of Camellia oleifera 50~100 cm above the ground was sawed off (as shown in Figure 2 and Figure 3).

1.2 scion preparation

Macheng City has more than 600 varieties of fine camellia, you can choose valuable varieties such as Magu Fairy, Huafoding, Shiba Scholar, Zhuangyuanhong, White Peony, Red Hibiscus, Fenxia and so on as scions. selecting lignified or semi-lignified branches of mature camellia trees which are fully developed, robust, full in axillary buds, robust in growth, free of diseases and insect pests and 1 - 2 years old as scions, wherein the branches are 5 - 10 cm in length and more than 0.25 cm in base thickness, the growth potential is stronger after grafting, and flower buds are formed early. The scions collected should be marked well and cloned. If long-distance transportation is required, it should be collected in the morning and evening or in cool weather, and attention should be paid to temperature control and moisture preservation during transportation.

2 Grafting

2.1 grafting time

Camellia oleifera high grafting time in early may to early june and other late spring and early summer season, autumn can also be appropriate grafting.

(1)Spring grafting. Spring is neither cold nor hot, sap flow rate is moderate, plant callus is easy to produce and heal, grafting survival rate is high. The best grafting time of Camellia is in early May in Macheng City, when the rootstock has not completely sprouted and leaves are displayed. At this time, it is the best time to select scion and graft Camellia. After grafting, the crown recovers quickly, which can advance the flowering and viewing period.

(2)Grafting in summer and autumn. In summer, the temperature and humidity are higher, the phloem cortex of Camellia oleifera is distinct, which is convenient for scion grafting. At this time, the rootstock and scion cambium cells are very active, which is easy to form callus, and the grafting survival rate is high. Because young branches are rich in growth hormones, grow fast and have high grafting survival rate, the scion grafted by Camellia is often used as scion with 1~2 year old branches. Grafting seedlings with Camellia oleifera as rootstock can be carried out in early June in summer. Because the rootstock of Camellia oleifera has consumed a lot of nutrients to complete germination and leaf expansion in summer, it is difficult to provide nutrient supply for high grafting and seed replacement of Camellia oleifera. The growth potential of grafted plants is not strong, and the resistance to diseases and insect pests is not strong. Autumn temperature drops gradually, humidity decreases, grafting survival period is long, grafting should pay attention to moisture at this time, grafting survival rate is not high. In the process of high grafting and seed replacement of camellia, attention should be paid to the growth after grafting in spring. If grafting fails or the effect is not good, a small amount of supplementary grafting can be carried out in summer and autumn to improve the survival rate of grafting.

2.2 grafting technology

(1)Cutting ears. The fresh scion collected should be treated with moisture before grafting. First, the scion should be treated with water spray and covered with plastic film. When grafting, the fully developed axillary bud or terminal bud should be selected. The lower end of the leaf bud should be cut into thin wedge shape at 0.5 cm, the length of the surface should be about 1 cm, and the two sides should be evenly smooth. Then the scion should be cut off at the upper part of the bud tip at 0.5 cm to become a scion. When cutting ears, the knife should be sharp and sharp, and the knife should not be turned back on the cutting surface (Figure 4). To prevent transpiration of water, the scion leaves need to be cut in half, leaving half for photosynthesis. In order to keep moisture before grafting, it is best to put the cut scion in a basin filled with clean water.

(2)Cutting anvil. Clean the cross section of rootstock with clean towel first, then cut the saw cut of rootstock flat with grafting knife, cut two parallel knives from top to bottom at both ends of rootstock, like "door", deep into xylem, and then lift up the bark (Figure 5).

(3)Spike. Insert the peeled scion into the rootstock groove with torn bark, align the inner cutting surface of scion with rootstock, and then cover the torn rootstock bark on the scion (Figure 6).

(4)Bandaging. After inlaying ears, the grafting parts should be immediately bandaged with plastic bandages. When bandaging, the buds should not be damaged. The grafting parts should be bandaged tightly as possible.

(5)Cover. In order to keep the humidity of the grafted seedlings, a plastic cover should be tied to the scion after wrapping. The plastic cover is lantern shaped at the position of the grafted bud, and the plastic cover should be strictly prevented from touching the leaves of the scion to avoid burning the leaves. The bound plastic cover should be tight and airtight, otherwise it will not play a role in moisture retention and affect the survival of grafted seedlings (Figure 7, Figure 8).

3 Management after grafting

3.1 Management of plastic covers

After grafting, it is necessary to quickly put a plastic bag on the plastic cover to ensure that the relative humidity in the bag reaches more than 95%. After grafting, prevent insects from biting the moisturizing bag. If damaged, replace the moisturizing bag immediately. About one month after grafting, scion grows rapidly. At this time, a small hole can be cut in the bag to make the branches and leaves of scion grow properly ventilated. When the new plant grows to about 2 cm, the buds of Camellia sinensis grow steadily and the color of Camellia leaves turns dark green. After that, the moisture bag can be cut open or removed in the evening, but it still needs shade for 1-2 weeks. Because camellia branches grow quickly after high grafting, small sticks should be tied near the interface as support after grafting, which is convenient to expand the space of plastic cover and ensure that scions are not broken by wind. (Figure 9).

3.2 degerminating

Because of thick trunk, most hidden buds on the original trunk may germinate after grafting. If the buds of Camellia oleifera are not removed in time, the buds will grow too fast, which will inevitably compete with the scion of Camellia oleifera, and finally lead to the slow growth of scion of Camellia oleifera until it stops and finally dies. Therefore, we should clean up the buds of Camellia oleifera on rootstock in time to ensure the rapid growth of new shoots after grafting.

3.3 water and fertilizer management

After Camellia oleifera was grafted, proper humidity should be kept at the interface of the grafting, which could promote the formation of callus. In addition, the grafted trunk needs water and fertilizer due to cutting stock and interface healing, so it must be timely applied nitrogen fertilizer, a small amount of multiple times, combined with irrigation, watering when dry, not waterlogging, to promote rapid growth of plants, and increase leaf area of plants, enhance photosynthesis, and improve various growth quantities of plants.

3.4 pest control

Camellia itself has no unique diseases and insect pests, but special attention should be paid to prevent common insects such as chafers, scale insects and aphids from harming camellia shoots. When the damage is serious, the spawning branches and damaged branches of insects should be cut off first, and then the poison silk should be sprayed with 1 000~1 500 times solution; scale insects will infect camellia with bituminous coal disease. When serious, besides spraying poison silk every 10 days, it can be brushed with old toothbrushes or bamboo chips. Camellia mature branches are relatively stable, spring and summer may encounter leaf rollers, but generally will not form a greater harm, only need to directly pick off leaf rollers larvae can be. Summer high temperature and high humidity, special attention should be paid to strengthen management, in order to improve the disease resistance of plants, once the symptoms of branches and leaves are found, the diseased leaves should be removed as soon as possible, and fungicides should be sprayed at the same time to prevent the occurrence of gray spot disease and other pathogens.

3.5 training and pruning

Camellia branches too many buds will weaken the tree vigor, in order not to make it bloom in the next year after grafting, it is necessary to remove the buds to ensure rapid growth of Camellia branches, forming a good crown. In the late management of high grafting, attention should also be paid to cutting off dense branches, cross branches, diseased branches and overlapping branches, so as to make the tree beautiful, luxuriant foliage, but also improve the ventilation and lighting conditions of the crown; In addition, in order to speed up the metabolism of camellia after grafting and improve photosynthetic efficiency, some old leaves should be removed, and reasonable shaping and pruning must be carried out, so as to maintain the balance between vegetative growth and reproductive growth of camellia plants, ensure strong plant growth, and reduce the occurrence of diseases and insect pests.