Detailed Explanation of High-Efficiency Seedling Techniques for Taxus wallichiana var. mairei

Taxus wallichiana var. mairei belongs to the family Taxaceae and the genus Taxus. It is an evergreen large tree, an endangered plant worldwide, and is listed as a national first-class protected tree species. This tree species prefers a warm and humid climate and is mainly distributed in areas south of the Yangtze River basin below 1500 m in altitude. In our city, ancient trees are scattered in Liandu, Suichang, Qingtian and other places. The wood of Taxus wallichiana var. mairei has a fine texture, is lustrous and elastic, with purplish-red heartwood and strong decay resistance, making it a superior industrial timber; research has found that taxol and taxane extracted from its bark, roots and leaves have special preventive and therapeutic effects on cancer, leukemia and AIDS; Taxus wallichiana var. mairei has a quaint and dignified tree form, with verdant leaves. After autumn, the outer seed coat is bright red like blood and very attractive. When planted in shady areas of courtyards as a landscape tree, or combined with other tall trees to form ornamental groves, its ornamental value is extremely high. Therefore, Taxus wallichiana var. mairei is a plant that integrates medicinal, timber and ornamental uses, with high development and utilization value.

The seed coat of Taxus wallichiana var. mairei has poor permeability and a long dormancy period, making seed propagation difficult. To promote the production of seedlings, from 2002 to 2004 in Chenliao Village, Liandu District, 1.3 million seedlings were successfully propagated from seed, covering an area of 20 mu, with a seed germination rate of over 95% and a seedling survival rate of over 85%. At the same time, rapid propagation by cuttings was also carried out at the Lishui Institute of Agricultural Sciences, achieving a rooting rate of 50%-60%. The specific operations are introduced as follows:

1. Field sowing and seedling raising

1.1 Seed collection and storage

1.1.1 Seed collection and treatment. Local seeds of Taxus wallichiana var. mairei are collected in batches after mid-October, when the outer seed coat of the fruit turns dark red. After collection, the fruits are piled for one week, the outer seed coat is washed off, fine sand is added, and they are rubbed repeatedly to remove the waxy layer. The seeds are then soaked and disinfected in 0.3% potassium permanganate for 30 minutes, and the surface water is air-dried, ready for storage.

1.1.2 Seed storage. After collection, the seeds of Taxus wallichiana var. mairei have a one-year physiological maturation period, and can be stored by natural wet sand stratification or in a 5°C cold storage. Generally, sand storage is adopted, with a ratio of pure river sand to seeds of 3:1, stored indoors or in a cellar in a cool and ventilated place, turned over once every 1-2 months, and checked for pests and diseases, and protected against rodents.

1.2 Land preparation and sowing

1.2.1 Seedbed preparation. Select a plot with sufficient light, convenient drainage and irrigation, and deep, fertile, loose soil as the seedbed. Prepare the land into beds 1.5 m wide (net bed surface width 1.2 m, path width 0.3 m) and 20 cm high. While preparing the land and making beds, apply 1500 kg of decomposed organic fertilizer and 50 kg of quick-dissolving high-quality compound fertilizer per mu, and mix in 5-8 kg of carbofuran to control underground pests. Turn the fertilizer into the soil layer and level the bed surface. Ten days before sowing, apply 50 ml of 40% formalin per square meter, add 10-12 kg of water, sprinkle it on the soil, and cover with plastic film. Remove it 3-4 days before sowing, then sow.

1.2.2 Timely sowing. After one year of storage, some seeds have cracked and shown white. At this time, screen them out and wash them clean, float off the empty grains, soak and disinfect in 0.05% potassium permanganate solution for 10 minutes, then rinse clean with water, and sow after air-drying. Sowing can be done by broadcasting or by drilling in rows and spots: broadcasting is to evenly scatter the seeds on the bed, and cover the seeds with a mixture of screened plant ash and fine soil, until the seeds are no longer visible; for drilling in rows and spots, a specially made wooden funnel-shaped sowing trough 1.2 m long with an upper opening 5 cm wide can be used, sowing at a spacing of 5×10 cm, evenly sowing the seeds, and covering the seeds with screened plant ash and fine soil. Use 15 kg of seed per mu. After sowing, use Harness for surface weed control, lay plastic film, and build a small plastic film arch shed to increase temperature and retain moisture, and carefully prevent rodent damage.

1.3 Field management

1.3.1 Shading during the seedling stage. In early to mid-April, when the temperature has gradually stabilized and begun to rise, remove the film in time, cover with a shade net (shading rate 70% in the early stage, 50% in the later stage), cover tightly and securely, and carefully prevent wind damage, rodent damage and bird damage. Until the end of the fast-growing period, in mid to late September, remove the shade net on a cloudy or rainy day. The autumn shoots of Taxus grow rapidly and are tender, so the time of film removal is critical. If too early, the new shoots of the seedlings will be sunburned and turn yellow; if too late, it will affect the growth of side branches and hardening of the seedlings.

1.3.2 Pest and disease control. After the seedlings emerge, they are susceptible to infection by pathogens, causing root rot and damping-off. The key is "prevention". After the seedlings emerge, spray 800-fold Topsin or half-strength Bordeaux mixture every 7 days, used alternately, spraying on the seedling stems and the undersides and upper surfaces of leaves. Soil pests and diseases should also be prevented in time, by watering the roots with Dexon and phoxim, and adding carbofuran once in the middle stage.

1.3.3 Cultivation, weeding, fertilizing and watering. During the seedling growth period, pay attention to weeding and loosening the soil to improve soil aeration. The principle of weeding is: remove small ones, remove early ones. In the early stage of seedling growth, use 0.2% urea, applying once every month. In the middle and late stages, apply a specially prepared nutrient solution once every month, with the formula: calcium nitrate 550 mg/L, potassium nitrate 150 mg/L, magnesium sulfate 155 mg/L, potassium dihydrogen phosphate 135 mg/L, potassium chloride 750 mg/L, ammonium sulfate 750 mg/L, manganese sulfate 0.40 mg/L, zinc sulfate 0.06 mg/L, boric acid 0.65 mg/L, sodium molybdate 0.025 mg/L, chelated iron 0.65 mg/L. Water management can be combined with fertilization. Seedlings are afraid of waterlogging, so the field must not accumulate water.

1.4 Outplanting

Through careful management, one-year-old seedlings with a height of 15-35 cm, a ground diameter of 0.3 cm, and 3-5 side branches can be outplanted.

2. Greenhouse sowing and seedling raising

2.2 Sowing

2.2.1 Preparation of nutrient pots. Select 7 parts of high-quality fresh red loam soil, 2 parts of decomposed organic fertilizer, and 1 part of sand or perlite, and stir and pile them fully one month in advance. Build a plastic greenhouse. The nutrient pot specification is 8×12 cm. Adjust the moisture content of the nutrient soil, fill the nutrient soil, and arrange them neatly in beds.

2.2.2 Timely sowing. In early October, increase the moisture content of the seeds during storage so that they show white earlier, and they can be sown at the end of January the following year. One seed per pot.

2.3 Seedling stage management

Remove the film in time, cover with a shade net, prevent pests and diseases, cultivate and weed, fertilize and water.

2.4 Outplanting

Through careful management, one-year-old seedlings are 30 to 50 cm high, with a ground diameter of 0.5 cm and 6-10 side branches, yielding 20,000 high-quality seedlings per mu.

3. Rapid propagation by cuttings

The mother trees from which detached materials are cut are best 3-8 years old. Cut semi-lignified branches of the current year as cuttings, preferably at around eight in the morning. After cutting the branches, immediately put them into a plastic bucket filled with clean water to prevent dehydration and drying. Then bring them indoors for cutting into fixed segments. Each detached material segment is 10-15 cm long, retaining 3-5 axillary buds or lateral terminal buds. The cut should be flat and smooth, not torn, and the lower end should be even. Soak in a prepared indolebutyric acid solution of 100 ppm, with a soaking depth of about 5 cm, for 18 hours (or treat with 200 ppm indolebutyric acid for 2-4 hours). Then insert the cuttings into a seedbed with river sand or perlite as the substrate. The seedbed should be 1.2 m wide, with a suitable length. The cutting depth is 5-8 cm, and the row-to-plant spacing is 4×8 cm. Spray water immediately after insertion. Build a frame on the seedbed, cover with a shade net, and start the plant rapid propagation simulation computer. After 2 months, the rooting rate generally reaches 50%-60%, and after 3 months they can be transplanted.