The Latest Taxus (Yew) Propagation Techniques and Methods Tutorial

Taxus propagation techniques fall mainly into 3 types: sexual propagation, asexual propagation and micro-cutting propagation. Below we will explain these three Taxus propagation techniques in detail.

Sexual propagation of Taxus  

In earlier years, the seedling emergence rate of wild Taxus sown from seed was less than 10%. Scientific research has found that its seeds have a dormancy period lasting several years; after using outdoor alternating-temperature storage and applying drugs to break seed dormancy, the emergence rate can be raised to more than 70%-80%, breaking through the difficulties of sexual propagation in common Taxus and making artificial mass seedling cultivation and large-area planting possible. 

1. Seed collection: Collect ripe fruit from September to October, put it in a basin, add an appropriate amount of coarse sand and water, rub and wash repeatedly on a wooden board to remove the outer peel and pulp of the seeds, then rinse repeatedly with clean water and set aside. 

2. Seed soaking: Before sowing, first soak in a 1:1 mixture of 50-degree baijiu and 40-degree warm water for 20 minutes, then remove and soak in 500 P P M gibberellin for 24 hours, which can induce the production of hydrolytic enzymes and promote germination. 

3. Sowing: Experiments show that the fresher the seeds, the higher the emergence rate. Seeds sown within one week after collection can reach a germination rate of more than 90%, while seeds sown at the Start of Spring have a germination rate of only 50%, so seedlings should be raised immediately after seed collection in September and October. For the seedbed method, make it 1.2 m high, and the length is calculated by seed quantity at 100 sq m of seedbed per kilogram of seed. When turning the soil in the seedbed, apply farmyard manure, 100 kg of phosphate fertilizer and 30 kg of nitrogen fertilizer per mu. Use 2 kg of powdered insecticide to kill underground pests, then open drainage channels and set aside. Dry the surface water of the soaked seeds, add an appropriate amount of fine sand to facilitate broadcasting, evenly broadcast at a rate of 5 kg per mu onto the seedbed, water thoroughly with clean water, and shortly after cover with the prepared fine soil at a thickness of about 1 cm. 

4. Seedling care: After sowing, cover the seedbed flat with plastic film; after the Start of Spring, change the flat film to an arched film and begin raising the temperature to force germination. Check temperature and humidity at any time; if the temperature is too high, uncover one side of the agricultural film to cool it down. After germination begins, water the seedlings about once every 4 days. When the small seedlings have two leaves and one heart, remove the film to harden the seedlings and thin them for sparser planting. When the seedlings grow to 5 cm tall, thin the dense areas to maintain a basic stand of 20,000 plants per mu, and heel in the thinned seedlings in other plots at a spacing of 15×20 cm. Weeding and topdressing during the seedling stage: weeds often grow in the nursery and can be pulled by hand or removed along with loosening the soil; after each soil loosening, apply 10 kg of urea per mu, 5 kg of potassium chloride, and decomposed farmyard manure. During the seedling stage, topdressing is needed three times to ensure strong seedlings. During the seedling stage, spiders, aphids, green caterpillars and the like may appear and can be controlled by spraying dichlorvos, dimethoate and similar insecticides. After growing in the seedbed for one year, when the seedlings are more than 30 cm tall with a stem diameter of 0.3 cm, they can leave the nursery for afforestation. 

Asexual propagation of Taxus

Asexual propagation is mainly cutting propagation. Taxus media is a hybrid variety, and to maintain the purity of the variety it is generally limited to asexual propagation. 

1. Time. In spring it can be done from February to April, and in autumn from September to November. During this period the temperature is generally above 15°C and below 25°C, ensuring reduced water evaporation from the cuttings and root healing. 

2. Cuttings. For cutting propagation, the scions should first be pest- and disease-free, vigorous branches, 0.3 to 0.8 cm thick and 10 to 15 cm long. After cutting, first remove the leaves from the lower 1/3 of the branch, place it in rooting solution to soak for two hours, then insert it into the seedbed promptly. 

3. Seedbed. If conditions permit, make the seedbed inside a greenhouse; the substrate can use perlite or vermiculite. For small-scale propagation, sandy soil with 1/3 humus soil added can be used. The seedbed can be made 1.2 m wide, with length depending on the number of seedlings to be raised; the substrate layer is about 20 cm thick. First irrigate to settle the substrate, then carry out cutting. 

4. Cutting. Insert the prepared cuttings into the seedbed at a plant spacing of 4 cm and a row spacing of 10 cm, with 1/3 of the cutting inserted into the soil. 

5. Management. Spring cuttings generally take 30 days to root, while autumn cuttings generally root the following year, so seedbed management is the key to cutting survival. Water promptly after insertion. On the seedbed, use bamboo strips to arch a frame 15 cm above the ground, lay film flat over the frame; for spring cuttings remove the film after April and cover with a shade net; for autumn cuttings, the film must remain covered until April of the following year, and when the temperature is high also replace it with a shade net. The film is mainly used to maintain humidity in the seedbed, and in winter it can also increase the seedbed temperature. A shade net with a 80% shading rate generally gives better results. For large-scale propagation, the shade net should be set about 2 m above the ground; for small quantities, covering the seedbed is enough. After insertion, if the leaves remain green, neither withering nor yellowing, it indicates normal management. After 20 days, pull one out to check whether the cut at the base of the cutting shows signs of healing and cell tissue growth; this is an important sign before rooting.

Spring cuttings root soon after the cell tissue increases; for autumn cuttings, after this cell tissue increases, as the temperature drops, rooting waits until after February of the following year when the temperature rises, and then new roots continue to grow from the original cell tissue. However, this tumor-like tissue also has the function of absorbing water and nutrients and can maintain the cutting's own water requirements. After new roots grow, fertilizer can be applied as topdressing, using 20 jin of urea and 5 kg of compound fertilizer per mu of seedbed, applied by irrigation; before leaving the nursery, topdressing can be applied 2 times, and the fertilizer amount can depend on seedling condition. Foliar fertilizer can be applied after 10 days, generally sprayed once every 20 days; in the early stage it can promote root healing, and after rooting it can promote root growth and the growth of upper small branches. During the seedling stage, weeds in the seedbed should be removed frequently to prevent them from competing with the seedlings for water and nutrients. Spring cuttings basically develop a well-developed root system after September of the same year, reaching about 20 roots, with roots about 15 cm long, and the upper part sends out 3 to 5 new branches more than 10 cm long. Autumn cuttings begin to grow roots after February of the following year, and after June can be heeled in or transplanted (transplanting is not suitable in June and July when the temperature is too high), or they can continue to be managed in the seedbed, and after September can be transplanted. Autumn cuttings have a longer growth period and grow better than cuttings from the same year. No matter which cutting method is used, as long as management is done well, the survival rate can reach more than 90%, making it the main propagation method for developing Taxus media at present. 

Micro-cutting propagation method for Taxus

The micro-cutting propagation method is also called the “non-test-tube tissue culture method”. Its characteristic is that it can increase the propagation multiple of limited material, and it is used when the number of mother trees is small; moreover, the propagation cost is low and the propagation quantity is large. The disadvantage is that the seedling stage is extended by 1 year before transplanting, and after rooting it needs to be heeled in for 1 year before reaching the requirements for leaving the nursery. The propagation technique is relatively demanding and can only be used with a certain technical foundation and production conditions. Cover with a shade net on top, keep the seedbed moist at all times, and strictly prohibit direct sunlight. As long as the leaves do not yellow or wither and remain green, it indicates normal growth. After about 20 days, check whether the cut at the base of the cutting has healed and whether cell tissue has grown; this is the main state before rooting. During this period, foliar nutrient fertilizer can be applied as topdressing. After 40 days, check that new roots have grown, and nitrogen fertilizer can be applied by watering. At most two applications during the seedling stage. Generally, spring cuttings are transplanted in autumn, and autumn cuttings are transplanted before June of the 2nd year or in September. The standard for transplanting seedlings is that fibrous roots should be more than 20, root length 10 cm, and the upper part generally has about 3 new branches growing, 5—10 cm long.