Grafting Seedling technique of Alpine Rhododendron with large White Rhododendron as rootstock

Grafting Seedling technique of Alpine Rhododendron with large White Rhododendron as rootstock

Alpine rhododendron: small evergreen shrub, up to 1 m tall, densely branched, prostrate or erect. Leaves often scattered on top of branches, leathery, light gray to dark grayish green above, yellowish brown to reddish brown below, petiole scaly. Inflorescences terminal, umbellate, with several flowers, flower bud scales deciduous, calyx small, reddish or purple, Corolla broadly funnelform, lilac rose to purple, rarely white, filament base woolly, capsule oblong-ovate, flowering from May to July and fruiting from September to October. Born in high mountains, tundra, rocky places, or swamps. Produced in Daxing'an Mountains, Changbai Mountain and Inner Mongolia in Northeast China. There are also in Canada and Alaska. The flowers of this species can be planted in garden beds and can also be used as vases of cut flowers, which has high horticultural value. Alpine rhododendron is mostly used for potted ornamental plants. It likes cool and humid environment. Because of its large crown, it needs a lot of water. The root system is well developed, it is a shallow root tree species, the cultivation medium should be loose, rich in humus, the soil aggregate structure is good, and the pH value is between 5. 5% and 6. 5%. It is best to be planted in muddy tile pot. Alpine rhododendron is not resistant to high temperature, poor growth over 35 ℃, but can withstand severe cold of-10 ℃ [Jishan Huayao].

The problem of low sprouting rate of seed propagation was solved in the introduction and domestication of alpine rhododendron, but the seedling growth of seed propagation was very slow, which affected the popularization and application of alpine rhododendron. Grafting propagation takes only one year to blossom. The study of their grafting propagation law will play a positive role in their introduction and domestication and the development and utilization of resources.

The main results are as follows: (1) from March to April, the 4-year-old strong rhododendron plant was selected as the rootstock, the evenly distributed branches on the tree as the grafting point, and the budding 1-year-old branches of pure alpine rhododendron were selected in sunny weather. cut into a scion with 2-3 buds, the length of the spike is 6-8 cm, the cut is coated with ferrous chloride starch solution, and the plastic film is used to seal the system. The whole scion was covered with a wet towel with a temperature of 23 ℃ and a humidity of 93%. The mass fraction of ferric chloride in the starch solution dissolved with ferrous chloride is 0. 24%, the mass fraction of starch is 5. 0%, and the rest is water.

(2) before grafting, the bottom of the scion was dipped in 110ppm naphthalene acetic acid solution for 12 seconds, the lower end of the scion was cut into a wedge, cut vertically at the center of the grafting point of the rootstock, and the incision conformed to the wedge size of the scion. The scion was inserted into the incision of the rootstock to align the phloem of the rootstock with the scion, and then press the scion with the skin of the rootstock, then bind and wrap the whole scion with a black film belt. Prevent direct sunlight and Rain Water from getting wet after grafting. Among them, the branches on the grafting point of the rootstock remain 16 cm long, and the old branches and new buds on the rootstock will be cut off according to the tree type, with the remaining old branches accounting for 13% and the remaining new buds accounting for 8%.

(3) after 8 days of grafting, wet nutrient solution was sprayed at the grafting site in the morning and evening, the dosage was 9 ml / plant, and used continuously for 4 days. After 33 days of grafting, the scion sprouted and the black film band was removed. Normal cultivation and management can be carried out after 48 days of grafting. Liquid fertilizer was sprayed within 55 cm of the root of the rootstock every 16 days, with a dosage of 75 kg / mu. The nutrient solution was prepared by the following components according to the mass percentage: ferrous sulfate 0. 19%, ethylenediamine tetraacetic acid 0. 33%, potassium dihydrogen phosphate 0. 11%, ammonium nitrate 0. 14%, magnesium sulfate 0. 09%, potassium iodide 0. 13%, zinc sulfate 0. 07%, copper sulfate 0. 17%, sodium molybdate 0. 06%, and the rest is water. The fertilizer liquid is made of the following components according to the mass percentage: urea 3. 3%, potassium sulfate 2. 2%, calcium chloride 1. 9%, ammonium nitrate 1. 6%, organic fertilizer 1. 3%, fermented cake fertilizer 0. 9%, manganese sulfate 0. 6%, the rest is water.