How to graft Camellia oleifera rootstock? Camellia oleifera is an evergreen shrub or small tree of Camellia of Theaceae. It is one of the top ten traditional famous flowers in China. It is not only suitable for family potted plants, but also suitable for landscaping. It has high ornamental value. It is one of the five golden flowers (azalea, chrysanthemum, camellia, rose and apricot) developed in Macheng. Camellia oleifera cultivation in Macheng has a long history. Because some camellia oleifera in Macheng are small and old trees with low fruit, these low-yield camellia oleifera can be used as rootstocks to graft camellia, so the cultivated camellia is big, long-lived and has high ornamental value. Among various propagation techniques of camellia, grafting is an important means to expand and accelerate the propagation of fine varieties. Grafting Camellia oleifera as rootstock can not only retain its original excellent characteristics, but also improve its adaptability to the environment. At the same time, it can increase the growth of Camellia oleifera, bloom ahead of time and prolong the viewing time of Camellia oleifera. Camellia grafting technology can form a good crown in the second year of grafting, so grafted seedlings grow faster than sowing seedlings and cutting seedlings, which greatly improves the growth speed of camellia. This grafting technique has been widely used in Wunaoshan National Forest Park in Macheng City. After grafting on Camellia oleifera, more than 600 varieties of Camellia oleifera have been cultivated in Macheng, and Camellia oleifera cultivation in Macheng has a history of 1600 years.
Experimental 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, at the southern foot of the middle Dabie Mountain, at the junction of Hubei, Henan and Anhui provinces, with latitude of 30 52 ′ ~ 365 438+0 36 ′ and longitude of 65 438+04 40 ′ ~ 65 438+066. At an altitude of 25 ~ 1337 m, it belongs to subtropical continental monsoon climate, with the characteristics of abundant sunshine, mild climate, abundant rain, the same season of rain and heat and distinct four seasons. The annual average rainfall is 1223.7mm, the maximum rainfall in wet years is 2009.0m( 1954), and the minimum rainfall in dry years is 683mm( 1978), which is unevenly distributed during the year, and May-September is the flood season. The annual average temperature is 65438 06℃. The extreme maximum temperature is 4 1.5℃( 1959) and the minimum temperature is-15.3℃( 1977 in January). The annual sunshine hours are 2036.7 ~ 2 153. 1h, and the sunshine percentage is 46% ~ 49%. The total radiation energy is108.2 ~113.3 ka/cm2. Frost-free period 228d. There are yellow brown soil, fluvo-aquic soil and paddy soil. The range of soil pH is 5.60 ~ 6.68, the range of soil organic matter content is 0.6% ~ 2.5%, the range of total nitrogen content is 0.5% ~ 0.2%, the range of alkali-hydrolyzable nitrogen content is 30 ~ 15 ppm, and the range of available potassium content is 30 ~ 200 ppm.
1 Preparation before grafting
1. 1 rootstock preparation
(1) Selection and transplantation of low-yield Camellia oleifera forest. The transformation of low-yield camellia oleifera can not only reuse resources, but also greatly shorten the rootstock cultivation time. In the existing low-yield Camellia oleifera forest, trees with tree age of 30-50 years, ground diameter of 5- 10 cm, strong growth and no pests and diseases are selected as rootstocks (Figure 1).
(2) The rootstock is trimmed before grafting. 1~ Before grafting Camellia oleifera in February, the long branches, dead branches, weak branches, diseased branches and overlapping branches of the rootstock should be cut off, so as to facilitate ventilation and lighting, reduce the occurrence of diseases and pests, avoid useless nutrient consumption, make the plant grow sturdily and ensure the vigorous growth of the rootstock. Before grafting, cut off the trunk of Camellia oleifera 50 ~ 100 cm from the ground (as shown in Figure 2 and Figure 3).
1.2 scion preparation
There are more than 600 excellent camellia varieties in Macheng, and precious varieties such as Magu Fairy, Flower Buddha Ding, Eighteen Bachelor, Zhuangyuanhong, Red Hibiscus and Pink Xia can be selected as scions. Woody or semi-woody branches of mature tea trees (1 ~ 2 years old) are selected as scions, which are well developed, stout, full of axillary buds, robust in growth and free from pests and diseases. The branch length is 5 ~ 10 cm, and the base thickness is more than 0.25cm. After grafting, the growth vigor is strong and the flower buds form early. When scions are picked and grafted, the collected scions should be marked and cloned. If long-distance transportation is needed, it should be collected in the morning and evening or when the weather is cool, and attention should be paid to temperature control and moisturizing during transportation.
2 grafting
2. 1 grafting time
The grafting period of Camellia oleifera is usually from early May to early June in late spring and early summer, and grafting can also be appropriate in autumn.
(1) Spring grafting. Spring is neither too cold nor too hot, the sap flows at a moderate speed, the callus of plants is easy to produce and heal, and the grafting survival rate is high. The top grafting of camellia is suitable for spring, and the best grafting time in Macheng is early May, when the rootstock has not fully germinated and spread its leaves. This is the best time to choose camellia scion grafting. After grafting, the crown recovered quickly and the flowering and ornamental period could be advanced.
(2) Grafting in summer and autumn. In summer, the temperature is high and the humidity is high, and the phloem cortex of Camellia oleifera is distinct, which is convenient for grafting Camellia oleifera scions. At this time, the cambium cells of rootstock and scion are very active, which are easy to form callus and have high grafting survival rate. Because the shoots are rich in growth hormone, grow fast and have high grafting survival rate, 1 ~ 2-year-old branches are often used as the scion of camellia oleifera grafting. Grafting seedlings with camellia oleifera as rootstock can be carried out in early June in summer. Because the rootstocks of Camellia oleifera have consumed a lot of nutrients when they germinate and spread their leaves in summer, it is difficult to provide nutrients for highly grafted Camellia oleifera, and the growth potential and pest resistance of grafted plants are not strong. In autumn, the temperature gradually drops, the humidity decreases and the grafting period is long. At this time, grafting should pay attention to moisturizing, and the survival rate of grafting is not high. In the high grafting of camellia, attention should be paid to the growth after grafting in spring. If the 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 grafting survival rate.
2.2 Grafting technology
(1) pruning. Before grafting, the harvested fresh scions should be fully moisturized. First, the scion should be sprayed with water and covered with plastic film. When grafting, well-developed axillary buds or terminal buds should be selected. The lower ends of both sides of the leaf buds should be cut into thin wedges, with a section length of about 65438±0cm, and both sides should be even and smooth, and then cut off 0.5cm above the bud tip to become scions. When cutting the ear, the knife should be sharp, and the knife should not be returned on the cutting surface (Figure 4). In order to prevent the transpiration of water, half of the leaves on the scion need to be cut off, leaving half for photosynthesis. In order to keep moisture before grafting, it is best to put the cut scion into a basin filled with clear water.
(2) cutting the anvil. First, clean the cross section of the rootstock with a clean towel, then smooth the kerf of the rootstock with a grafting knife, cut two parallel knives at both ends of the rootstock from top to bottom, which looks like a "door" until it reaches the xylem, and then lift the bark away (Figure 5).
(3) cutting. Insert the cut scion into the groove of the rootstock with torn skin, align the inner surface of the scion with the rootstock, and then cover the scion with the torn rootstock skin (Figure 6).
(4) dressing. After cutting, the grafting site should be immediately bandaged with plastic bandage, and the grafting site should be tightly bandaged as far as possible without damaging the bud.
(5) cover. In order to maintain the humidity of grafted seedlings, a plastic cover should be tied at the scion after dressing change, and the plastic cover is lantern-shaped toward the scion, so as to strictly prevent the plastic cover from contacting the scion leaves to avoid burning the leaves. The bound plastic cover should be tightly airtight, otherwise it will not keep moisture and affect the survival of grafted seedlings (Figure 7 and Figure 8).
3 Management after grafting
3. 1 management of plastic cover
After grafting, put a plastic bag on the plastic cover quickly to ensure that the relative humidity in the bag reaches above 95%. Prevent insects from biting the moisturizing bag after grafting. If damage is found, the moisturizing bag should be replaced immediately. About one month after grafting, the scion grows rapidly. At this time, a small hole can be cut on the bagging, so that the branches and leaves of the scion can be properly ventilated. When the new branches grow to about 2cm, the camellia leaves grow stably and the color of the camellia leaves turns to dark green, the moisturizing bag can be cut or put in the evening, but it still needs shading 1-2 weeks. Because the branches of camellia sprout quickly after high grafting, a small stick should be tied near the interface as a support after grafting, which is convenient to expand the space covered by plastic and ensure that the scion is not broken by the wind. (Figure 9).
3.2 In addition to sprouting tillers
Because the trunk of grafted Camellia oleifera rootstock is thick, most of the hidden buds on the original trunk may germinate after grafting. If the buds of Camellia oleifera are not removed in time, the new buds will grow too fast, which will inevitably lead to nutritional competition with Camellia oleifera scions, which will eventually lead to slow growth until it stops and finally dies. Therefore, it is necessary to clean up the buds of Camellia oleifera on the rootstock in time to ensure the rapid growth of new shoots after grafting.
3.3 Water and fertilizer management
After grafting Camellia oleifera, the grafting interface should keep proper humidity, which can promote the formation of callus. In addition, the grafted trunk needs water because of cutting rootstocks and joint healing, so it is necessary to topdressing nitrogen fertilizer in time, a small amount of times, combined with irrigation, watering during drought, and not waterlogging, so as to promote the rapid growth of plants, increase the leaf area of plants, enhance photosynthesis and improve various growth of plants.
3.4 Pest control
Camellia itself has no specific pests and diseases, but special attention should be paid to prevent common insects such as scarabs, scale insects and aphids from harming the new shoots of Camellia. When the damage is serious, cut off the insect spawning branches and damaged branches first, and then spray the poisonous silk book with 1000 ~ 1500 times of liquid. Scale insects can infect camellia with bituminous coal disease. In severe cases, in addition to spraying poisonous silk once every 10d, you can also brush it off with an old toothbrush or bamboo chips. The mature branches of camellia are relatively stable, and they may encounter leaf roller moths in spring and summer, but generally they will not cause great harm. Just pick the leaf roller moths directly. Summer is hot and humid, so special attention should be paid to strengthening management. In order to improve the disease resistance of plants, once symptoms are found in branches and leaves, the diseased leaves should be removed as soon as possible, and fungicides should be sprayed at the same time to prevent the invasion of pathogens such as gray leaf spot.
3.5 plastic decoration
Too many buds on camellia branches will weaken the tree. In order not to make it bloom in the second year after grafting, it is necessary to remove flower buds to ensure the rapid growth of camellia branches and form a good crown. In the late management of high exchange grafting, attention should also be paid to cutting off dense branches, cross branches, disease and insect branches and overlapping branches, so as to make the tree beautiful and flourish, and at the same time improve the ventilation and lighting conditions of the crown; In addition, in order to accelerate the metabolism of grafted camellia and improve photosynthetic efficiency, some old leaves must be removed, so as to keep the balance between vegetative growth and reproductive growth of camellia plants, ensure the healthy growth of plants and reduce the occurrence of pests and diseases.