The latest course of breeding techniques and methods of Taxus chinensis

Taxus propagation techniques are mainly divided into three kinds, sexual reproduction, asexual reproduction and micro-insertion propagation. Below, we will describe these three propagation techniques in detail.

Sexual reproduction of Taxus mairei

In previous years, the emergence rate of wild yew seeds was less than 10%. Scientific research has found that the dormancy period of its seeds is as long as several years. After outdoor variable temperature storage and the use of drugs to break seed dormancy, the emergence rate can be increased to more than 70% and 80%, making it possible for the sexual reproduction of Taxus mairei to break through difficulties and to plant seedlings in large quantities.

1. Seed collection: collect mature fruits from September to October, put them in a basin, add an appropriate amount of coarse sand and water, scrub repeatedly on the board, scrub off the outer skin and pulp of the seeds, and then rinse them with water for use.

2. Soaking seeds: before sowing, soak in 50 degree liquor and 40 degrees warm water 1 ∶ 1 for 20 minutes, then soak it in 500p P M gibberellin for 24 hours, which can induce hydrolase production and promote its germination.

3. Sowing: the experiment shows that the fresher the seed, the higher the emergence rate. The germination rate of sowing seeds within a week after seed collection can reach more than 90%, and that of the Beginning of Spring sowing seeds is only 50%. Therefore, seedlings are raised immediately after seed collection in September and October, with a height of 1.2m and a seedbed of 100m2 per kilogram in length. The seedbed is combined with turning the soil and applying farm manure, with 100 kg of phosphorus fertilizer and 30 kg of nitrogen fertilizer per mu. Use 2 kilograms of powder insecticides to kill underground pests, and then open ditches for backup. Dry the soaked seeds in surface water, add an appropriate amount of fine sand, sow them evenly on the seedling bed at a dosage of 5 kg per mu and water them thoroughly, and then cover them with prepared fine soil about 1 cm thick.

4. Seedling protection: after sowing, the flat film seedling bed is used. After the Beginning of Spring, the flat film is changed into arch film, and the temperature and humidity are checked at any time. If the temperature is too high, one side of the agricultural film can be opened to cool down. After starting to sprout, water the seedlings once in about 4 days. When the seedlings have two leaves, they should remove the thin film to refine the seedlings and plant sparsely. When the seedlings grow to 5 cm high, uniform the seedlings in the dense place, keep 20,000 basic seedlings in one mu, and pseudo-plant the seedlings to other plots with a row spacing of 15 × 20 cm. Weeding and topdressing fertilizer in the seedling stage, weeds often grow in the nursery, which can be removed manually or combined with loosening soil for weeding. After each loosening of the soil, 10 kg of urea per mu and 5 kg of potassium chloride are applied. Mature farm manure needs topdressing three times in the seedling stage to ensure strong seedlings. Spiders, aphids and fleshy green insects may appear in the seedling stage, which can be sprayed and controlled by dichlorvos and dimethoate. After growing in the seedling bed for one year, the seedling height is more than 30 cm and the rod diameter is 0.3 cm.

Asexual reproduction of Taxus chinensis

Asexual reproduction is mainly cutting propagation, Taxus mairei hybrid varieties, in order to maintain the purity of varieties, generally limited to asexual reproduction.

1. Time. Spring can be carried out from February to April, autumn can be carried out from September to November, during this time the temperature is generally above 15 ℃ and below 25 ℃, to ensure that the moisture of cuttings reduce evaporation and root healing.

2. Insert. The cuttings should be disease-free and pest-free, strong branches with a thickness of 0.3 to 0.8 cm and a length of 10 to 15 cm. The cut branches should first remove the lower part of the 3 leaves, soak them in rooting solution for two hours, and then insert them into the seedbed in time.

3. Seedbed. Conditional can be done in the greenhouse seedbed, the matrix can be used perlite, metatarsal stone. A small amount of propagation can choose sandy soil, add 1xpg 3 humus soil, the seedling bed can be 1.2 meters wide, the length depends on the seedling, the matrix part is about 20 cm thick, first irrigate to make the substrate firm before cutting.

4. Cutting. Insert the spare cuttings into the nursery bed at a distance of 4cm between the plants and 10cm between the rows, and insert the cuttings into the soil.

5. Management. Spring cuttings usually take 30 days to take root, and autumn cuttings usually take root next year, so the management of the seedling bed is the key to the survival of cuttings. Irrigate in time after cutting, arch the seedling bed into a frame 15 cm high above the ground with bamboo slices, lay the film on the shelf, remove the film after spring planting in April, cover the sunshade net, and transplant seedlings in autumn. The film will be covered until April of the following year, and the sunshade net will also be changed when the temperature is high. The main purpose of using the film is to maintain the humidity in the seedbed, and it can also increase the temperature of the seedbed in winter. Sunshade net generally use 80% shading rate is better. When rearing in a large area, the sunshade net should be about 2 meters off the ground, and a small amount can cover the seedbed. After sowing, the leaves remain green, neither withered nor yellow, indicating that the management is normal. After 20 days, the cuttings are pulled out to see whether there are signs of healing and tissue growth at the base of the cuttings, which is an important manifestation before rooting.

The spring seedlings take root after the increase of cell tissue, and after the increase of this kind of cell tissue in autumn, the temperature drops until the temperature rises after February next year before continuing to grow from the original cell tissue to form a new root. However, this nodular tissue also has the function of absorbing water and nutrients, and can maintain the demand of sowing its own water. After the new root grows, fertilizer can be applied at a rate of 20 jin per mu of urea per mu of seedbed and 5 kg of compound fertilizer. It can be applied twice before coming out of the nursery, and the amount of fertilizer can be determined according to the seedling condition. Foliar fertilizer can be applied after 10 days, usually once every 20 days, which can promote root healing at the initial stage, and promote root growth and upper branchlet growth after rooting. In the small seedling stage, the weeds in the seedling bed should be removed frequently so as not to compete with the seedlings for water and fertilizer. After September of that year, the roots of spring seedlings are basically developed, which has reached about 20, the root length is about 15 cm, and the upper part has 3 to 5 new branches with a length of more than 10 cm. Autumn seedlings begin to take root after February of the next year, and can be grafted or transplanted after June (the temperature in June and July is too high to be transplant), or continue to stay in the seedbed management, which can be transplanted after September, and the growth period of autumn seedlings is longer and better than that of the same year. No matter which kind of insertion method, as long as good management, the survival rate can reach more than 90%, is the current development of the main breeding method of Taxus mairei.

Micropropagation of Taxus chinensis var. mairei

The method of micro-insertion propagation is called "non-test tube tissue culture", which is characterized by increasing the reproduction multiple of limited materials, using it in the case of small amount of female parent trees, low reproduction cost and large reproduction quantity. The disadvantage is that the seedling period should be extended by 1 year before transplanting, and pseudo-planting for 1 year after rooting can meet the requirements of coming out of the nursery. The breeding technology is relatively high, and it can only be used if there is a certain technical basis and production conditions. Cover the sunshade net, keep the seedling bed moist at any time, and forbid direct sunlight, as long as the leaves are not yellow or withered, keep green, which means that the growth is normal. In about 20 days, you can check whether the cut at the base of the cuttings is healed and whether there is cellular tissue growth. This is the main state before rooting, during which foliar nutrient fertilizer can be applied. After 40 days, it is checked that new roots have grown, and nitrogen fertilizer can be applied with water and nitrogen fertilizer. At most two times in the seedling stage, the spring seedlings are generally transplanted in autumn, and the autumn seedlings are transplanted before June or September in the second year. The standard of transplanting seedlings should be more than 20 fibrous roots, and there are generally about 3 new branches in the upper part of the root length of 10 cm, with a length of 5 Mel 10 cm.