Cutting Propagation of Rhododendron

Plant reproduction methods have always been divided into sexual and asexual two categories. At present, the mass production of rhododendron mostly uses the cutting method of vegetative reproduction, which is one of the ways to ensure that the offspring are exactly the same as their parents, and it is a commercial way to reproduce the so-called clones that are the same as each other.

First, the breeding object:

Roughly speaking, for the largest species of leaves, the base temperature should be added when cutting and the air humidity should be high. At the end of June, we began to use a closed cutter, and the branches should be fully mature and about two-year-old branches would be suitable for use. The short alpine rhododendron creeping on the high mountain should be harvested in autumn when it is propagated, it is not necessary to increase the bottom temperature when it is inserted, and it should take root only under the condition of proper ventilation. Species with medium-sized leaves are required to be right between the two extremes.

Second, take the insert:

1. Pick up time:

Generally speaking, the varieties with medium or large leaves of evergreen rhododendron can get gratifying results from September 20 to the end of October.

As for the varieties of Yingshanhong which are easy to take root, it is the best time to use semi-mature branches to cut in the open field from the middle of June to the middle of July, when the air temperature is 20 ℃ and the ground temperature is 30 ℃. Mature branches are used for cutting indoors in autumn and winter, and the survival rate is very high.

2. Cuttings requirements:

With mature, robust, pest-free and highly resistant mother plants, it is best to take the branches that are planted under the shade or where there is only half-shade every day. 2 days before harvesting, the mother plant should be fully irrigated. Then pick the cuttings on a sunny morning or cloudy day and use various methods to keep the cuttings from withering. The length of cuttings should generally reach 10 cm, and the branches should be of medium thickness. If there are flower buds on the cuttings, it will affect rooting, and the flower buds must be removed before insertion.

Third, the preparation of the insertion:

1. Cut the cuttings:

The length of the cutter should be standardized (about 10 cm), and the lower incision is under the section. If the leaf blade is too large, cut off 1 beat 3 to 1 stroke 2. It is enough to leave 3 leaves on an insert.

2. The unique treatment methods of cuttings:

On the lower side of the cutter, cut off a piece of about 4 cm with a sharp knife, including the cortex, cambium and xylem. The length of the cut depth on each insert should be the same.

3. To ensure the balance between matrix humidity and ventilation.

Fourth, the treatment of rooting hormone:

1. Indolebutyric acid (IBA) has a very obvious effect on promoting rooting. After experiments, the cuttings were soaked in 150ppm (equal to 0.015%) indolebutyric acid aqueous solution for 18 hours. The cuttings should be immersed in the solution of this concentration at room temperature, and the immersion depth should not exceed 5 cm.

2. B9 can also be used to deal with cuttings. "B9" is a growth regulator, soaked in 2500-5000ppm (0.25Mel 0.5) aqueous solution for 5 seconds for 10 seconds, then inserted into the matrix.

Fifth, the preparation of matrix:

1. There are many basic kinds of rhododendron cuttings, one part of sand and one part of peat is commonly used, and the effect of cutting is very good. Peat should not be too finely crushed. If it is too dry, it should be moistened with water before use. Sand to choose coarse sand, wash before use, can not contain silt and other impurities. Sand size of 3 mm is best, even with 6 mm gravel, especially in the case of full light fog, large particles drain well. It has been suggested that cutting rhododendron with 1 hammer 3 coarse sand and 2 hammer 3 peat mixture is also good.

2. The pH and depth requirements of the matrix:

The pH of the matrix is required to be between PH4~4.5. After the matrix is matched, put it into the basin, shallow box or bed frame ready for cutting, the depth shall not be less than 7.5 cm. To prevent mosses, a layer of sand can be added.

3. After a batch of cuttings take root, the substrate should be replaced, and it should be replaced at most twice in a row, so as to avoid parasitism of miscellaneous bacteria.

4, used matrix and basin, bed frame, etc., should be disinfected, the most convenient is to use high-temperature steam.

Sixth, the temperature and light requirements of the matrix:

1, hotbed cutting cuckoo, some people call it "hot cutting method". The cutter for large-scale cutting in greenhouse usually uses a distance of 10 × 10 cm. After insertion, the soil is not pressed, but sinks by irrigation, and then covered with plastic film to make the internal humidity reach saturation. It is convenient to heat the bottom temperature with hot water pipes in the greenhouse, and the substrate can reach 20 ℃ 22 ℃. After about 3 months, after rooting, the bottom temperature can be reduced to 18 Mel.

2, light requirements: light, cutting in the open field to prevent direct sunlight, but also can not be too shaded.

Spray also has a certain shading effect, such as the frequency of spray is large, although each time is not long, there is no need for shading, that is, "all-light fog interpolation". But the drainage of the matrix must be good, summer with fog insertion method because of sunshine, sufficient water, exuberant photosynthesis, rooting is very good. Cutting under light can not be shaded, and try to achieve the best effect of light and humidity under manual control, whether it is "cold light source" (that is, fluorescent lamp) or "hot light source" (that is, incandescent lamp). It is best to apply both equally. It was 30cm away from the plant and irradiated with 18ml for 24 hours a day, and the effect was ideal. It is worth mentioning that the use of flash at night, cutting bed every 60 seconds flash 1 second light, every day 8 Mel 24 hours, the effect is also very good, and electricity can be greatly saved.

7. Management after taking root:

The cuttings of semi-mature branches must take root in August. Before transplantation, you can open the window or part of the shed, and gradually begin to breathe and adapt to the external environment. Prepare for the transplant. It can be transplanted after about 10 days of exercise. First transplant to a small basin or shallow box with a diameter of 8 centimeters, or you can go directly to the ground, but you have to go through the initial stage in a semi-shady environment. The soil in the basin and shallow box must be loose, with half peat and half sand, plus half rotten leaves. As the winter is approaching, the seedlings with primary roots should be protected beyond the first winter. In order to make the future plants short and round, the new shoots on the top should be cut off to promote the formation of lateral branches.

In the spring of the following year, the planting beds planted in the open field were prepared early and made into east-west beds with a specification of 10 × 2 (meters). The surface was covered with peat 10 cm thick, and then turned evenly into the topsoil. The planting distance of large leaf species can be reduced by 25 × 25 cm and small leaves can be reduced. After planting, the ground is covered with 5 cm thick leaves, pine needles or sawdust to reduce evaporation. Shading methods can be done with shading nets, wood chips, bamboo curtains, etc., but it is appropriate to require a light transmittance of 50%.

In the second year, we still have to take 1 or 2 times of heart extraction. Cuckoos like to be moist and afraid of high temperature, so sprinkler irrigation in summer should be carried out frequently. Adding fungicides, pesticides, chemical fertilizers and herbicides to irrigation water has become very popular, which can kill two birds with one stone.