1 cutting time
The cutting time of Photinia rubra should be adapted to local conditions. Cuttings are usually carried out in spring, summer and autumn in East China, and the general temperature is 18 ~ 37℃, and the most suitable cutting temperature is 28 ~ 33℃. Therefore, the cutting time in Fuyang City, Anhui Province is March in spring, June in summer and September in autumn. It was found that summer was the golden cutting season of Photinia rubra.
2 scion selection
When cutting, we should also pay attention to the choice of cuttings. Usually, mature and lignified annual branches are selected for spring cutting, while robust, lignified or semi-lignified branches are selected for summer cutting or autumn cutting. Cut the cuttings into 3 ~ 5 cm, cut the upper incision into a flat mouth, cut the lower incision into an oblique mouth, and cut it into one leaf and one bud, so as to facilitate the cuttings to produce callus and accelerate the cutting healing and rooting. The number of leaves left on the cuttings should be determined according to the size of the selected cuttings and the real-time temperature in the arch shed of the seedbed during cutting. Generally, when the cutting leaves are large and the cutting temperature is high (the real-time maximum temperature exceeds 28℃), there are relatively few leaves left, generally 0.5 leaves left; When the cutting leaves are small and the cutting temperature is low (the real-time maximum temperature is below 28℃), the leaf retention accounts for a large proportion, generally 1.0 leaf retention; There should be no leaves on the cuttings. Pay attention to spray moisturizing after cutting to prevent water loss from affecting the survival rate of cutting.
3 cutting equipment
3. 1 seedbed preparation
The seedbed soil should be loose, fertile, slightly acidic to neutral, and ensure that the seedbed is close to the water source, which is convenient for watering and drainage when encountering stagnant water. Seedbeds are generally based on high beds to facilitate drainage. First, the nursery was plowed and leveled, and pesticides were applied to control underground pests. Then a brick fence with a width of 24cm and a height of 14cm is used as the seedbed. The fence is 200.0 meters long and 2.4 meters wide. Then lay a layer of fine sand with a thickness of 2 cm at the bottom of the seedbed as a drainage layer. Then spread the cutting substrate on the shortlisted seedbed, level it, and keep the substrate thickness at about 7cm. The selection principle of cutting substrate is loose and breathable, which is convenient for water storage and drainage, easy for survival cuttings to transplant, and does not destroy the root system in the later stage. Clean sand or loess with fine sand is usually used as the base. Under special circumstances, if it is difficult to obtain sandy soil or loess, loose acidic soil with good soil quality, no extensive cultivation, clean soil quality and low organic matter content can also be used as matrix. Finally, 5cm fine sand was spread on the substrate as an intercalation, which was beneficial to the rooting of cuttings. No matter which substrate is selected, the selected substrate must be disinfected before cutting to prevent the cuttings from mildew and rot. Before the substrate is laid on the seedbed, it can be turned over for disinfection, or it can be sprayed and watered with potassium permanganate (1000 ~ 1500 times) or putrescine (15g potassium permanganate particles mixed with 15kg water) or 800 ~ 1000 times.
3.2 the erection of arch shed
The arch shed in the steel frame greenhouse is more conducive to the control of cutting environment. The sunshade net in the steel frame greenhouse can better control the temperature and humidity in the greenhouse. Seedbed arch shed A single arch simple shed is built above the fence of seedbed, with the arch height of 0.5 ~1.0m. The arch shed skeleton structure can be built with Vitex negundo or bamboo, and covered with PVC transparent plastic film, which requires the arch shed to be durable and convenient for seedling transplanting in the later period.
4 cutting process
The results showed that the rooting time of cuttings without rooting treatment was more than 30 days, while the rooting time of cuttings with rooting agent was only about 10d, so cuttings should take root before cutting.
Rooting agent is an auxin compound belonging to plant growth regulator and promoter. Commonly used rooting agents are indoleacetic acid, indolebutyric acid, naphthylacetic acid, royal rooting agent and BR rooting agent. The rooting agent used in this experiment is indoleacetic acid, which is diluted several times according to a specific ratio for later use.
The rooting treatment process of cuttings is as follows: 100 cuttings are tied into a bundle for rooting treatment, and 1/2 of the bundled cuttings are put into rooting agent for 2-3s, and then pulled out and placed. Rooting agent can be dried on the surface of cuttings before cutting. When cutting, the cuttings should not be inserted too deep into the seedbed, otherwise it is not conducive to the breathing and rooting of cuttings, and the insertion depth is generally not more than 2/3 of the cuttings. The row spacing of cutting plants is (3 ~ 4cm) × (3 ~ 4cm), and 1m2 can be used for cutting 600 ~ 1000 plants. It is not suitable for over-dense planting to cause rot, and it is not suitable for over-sparse planting to cause cost increase and low emergence rate. When cutting, pay attention to the same direction of leaves on cuttings, which is beneficial to the uniform illumination of cuttings in the same bed and the management after cutting. After cutting, water should be poured, and after the leaves are dry, carbendazim and rot fungi can be sprayed 800 ~ 1000 times. After the cutting is completed, it can be covered with plastic film and the edges can be compacted. A temperature hygrometer is placed in the shed to facilitate real-time monitoring of the situation in the shed.
5 Post-insertion management
After cutting, the seedbed should be tracked and checked frequently, and the moisture of the seedbed, the temperature and air humidity in the shed should be paid attention to. The air humidity in the shed shall not be lower than 80%, and the temperature in the shed shall not exceed 34℃. If the temperature is too high, spray it to cool down. Callus and roots began to germinate 10 ~ 15 days after photinia rubra cutting. During this period, according to the weather changes, we should do a good job of drainage in rainy days, shading in high temperature weather, insect prevention around the shade shed and so on. About 20 days after transplanting, check the rooting situation, and gradually ventilate the seedlings according to the rooting situation of transplanted seedlings. Generally, when the transplanted seedlings take root to 60%, the two ends of the shading film can be slightly opened for ventilation, and the shading light transmittance can be controlled at 50%. When all the seedlings take root and more than 50% germinate (see figure 1), the film in the shade shed can be gradually removed, and then the shade net can be gradually opened to start hardening the seedlings. After uncovering the film, it is necessary to strengthen fertilizer and water management and pest control. Fertilization should be based on the principle of thin fertilizer and diligent application, combined with spraying foliar fertilizer or low concentration water-soluble chemical fertilizer to promote the healthy growth of cuttings. Such as urea and 800 ~ 1200 times humic acid solution, sprayed or watered every 5 ~ 8 days.
6 Common problems and solutions
6. 1 Less rooting and slow speed.
The main reasons for this situation are improper selection and use of rooting agent and too little alcohol added when using it. Generally, the rooting agent should be dissolved in the 20% ethanol solution of the total liquid medicine, and then the ethanol solution should be slowly poured into the water and fully stirred before use. The prepared liquid medicine should be prepared with it or sealed for storage. Pull the cuttings with little and slow roots out of the seedbed, cut off the wound, and soak them with drugs again before inserting them back into the seedbed.
6.2 slow germination
High cutting density and high shading rate lead to less nutrient absorption, less light exposure to leaves and low root activity due to water accumulation in seedbed. The above problems should be solved according to the actual situation. If the cuttings are too dense, the cuttings with poor growth can be intermittently pulled out and replanted in other seedbeds. If the shading rate is large, the shading net can be opened appropriately to increase the light transmittance; If there is water in the seedbed, you can dig a small drainage ditch at the edge of the seedbed, monitor the water accumulation in time and make a response. After the cuttings take root and survive, liquid fertilizer can be used appropriately, diluted and sprayed in proportion, and gibberellin and cytokinin can be sprayed every 5 ~ 7 days to facilitate their rapid germination.
Figure 1 Cutting Rooting and Shooting
6.3 Common disease symptoms and preventive measures
Gray mold grows on the shoots, leaves and young stems of Photinia rubra. At first, the disease spots are small spots like water stains, then they expand into large gray spots with irregular shapes, and finally the infected parts are covered with gray mold layers until necrosis or rot. In this regard, attention should be paid to management, drainage and timely removal of the sick and disabled. 300 ~ 400 times of 50% carbendazim solution and 300 ~ 400 times of thiophanate-methyl solution can be sprayed evenly for prevention and treatment, and seriously ill patients can spray/kloc-0 once every 7 days, 2 ~ 3 times each time. Erythema mainly occurs on leaves. At the beginning, the lesion was brown. After expansion, the lesion is semicircular or irregular with black particles, which is serious in rainy season. Therefore, fertilization should be reasonable and nutrition should be balanced. It can be controlled by spraying 1000 ~ 1500 times banfuqing or 800 times 50% carbendazim wettable powder. Patients with severe illness should be sprayed once every 7 ~ 10d, and sprayed two or three times each time.