Propagation Methods and Key Technical Points for Gastrodia elata

I. Asexual Propagation

1. Cultivation period. Generally, winter planting is carried out in November, and spring planting in March-April, with winter planting being preferable.

2. Selection of seed tubers. White tubers and rice tubers are preferred, with each weighing 5 g-10 g being optimal. Select those with no disease spots, no wounds, no frost damage, no rot, a spindle-shaped body, and obvious bud eyes as seed tubers. Some also use arrow tubers as seed tubers, but the terminal buds must be removed.

3. Amount of seed tubers used. This should be determined by the size of the seed tubers and the number of fungal logs per pit. Generally, for each pit using 9-10 fungal logs, place 5-6 seed tubers per fungal log, weighing 50 g-60 g, and the amount planted per pit should preferably be about 500 g.

4. Cultivation methods. At present, the following 5 methods are mainly used in large-scale production. (1) Fungal log companion planting method. Dig a pit 40 cm deep, place the pre-cultivated fungal logs at the bottom of the pit with a spacing of 5 cm. Place seed tubers alongside each fungal log in parallel, and also place seed tubers at both ends of the fungal logs, with the seed tubers kept close to the fungal logs. Rice tubers are broadcast on both sides of the fungal logs. After planting one layer, fill with soil 3 cm-5 cm so that the underlying fungal logs are not visible. Then plant the second layer using the same method, and finally cover with soil 10 cm-15 cm thick, slightly higher than the ground. (2) Fungal log plus new fungal log cultivation method. Generally use 10 fungal logs: place 5 pre-cultivated fungal logs in the bottom layer, then place 5 new logs that have not been cultivated with fungus at intervals. Place seed tubers on both sides of the pre-cultivated fungal logs and plant according to the fungal log companion planting method. (3) Fungal bed cultivation method. When planting, dig open the pre-cultivated fungal bed and take out the upper 5 fungal logs. Leave the lower fungal logs undisturbed, plant seed tubers according to the fungal log companion planting method, and fill with soil 3 cm-5 cm. Then use the upper 5 fungal logs to plant the second layer, and then cover with soil 10 cm-15 cm. This method has a high inoculation rate, quick survival, and high yield. Alternatively, when planting, open the pre-cultivated fungal bed, take out 5 fungal logs, add 5 new logs, and replant one pit, then use the 5 removed fungal logs plus 5 new logs to plant another pit. (4) Bed cultivation method. In mountainous areas, make beds in forests or on slopes at the forest edge, leaving a 30 cm working path between two beds. Loosen the soil at the bottom of the bed to facilitate drainage. Place fungal logs flat with a spacing of 5 cm-6 cm, add humus soil while placing them, and plant according to the fungal bed cultivation method; one or two layers may be planted. (5) Box cultivation method. The box cultivation method is not limited by site or soil quality and can make full use of idle open space, courtyards, and indoor conditions. This method makes it easy to control temperature and humidity, saves labor and materials, and is simple to carry out. The size of the cultivation box is not strictly required; generally, length 60 cm, width 45 cm, and height 30 cm are sufficient. Usually, the cultivation soil is mostly made by mixing broadleaf tree sawdust, fine sand, and humus soil in a ratio of 1:1:1. However, sawdust must not be too much, otherwise it easily ferments and raises the temperature, harming Gastrodia elata and Armillaria mellea. Method: generally use 4-6 fungal logs per box and plant 250 g of seed tubers. In winter in the north, the box can be moved indoors, and after spring warms up, moved outdoors again; in summer in the south, it should be moved indoors and appropriately sprinkled with water to maintain suitable temperature and humidity.

II. Sexual Propagation

Sexual propagation of Gastrodia elata can not only prevent germplasm degeneration from long-term asexual propagation, but also expand the source of seed material and increase yield. Gastrodia elata seeds are extremely small and simple in structure, consisting of an embryo and a single-layer seed coat, with no endosperm; the embryo has fewer than 100 cells, so the germination rate is extremely low. Under natural conditions, they generally do not germinate easily, and even if a very small number of seeds germinate, it is difficult for them to establish a nutritional relationship with Armillaria mellea, and the survival rate is very low. Therefore, artificial cultivation is relatively difficult and the technical requirements are relatively strict.

1. Cultivate the fungal bed. In March-April, select good-quality fungal logs as raw materials and cultivate them according to the method for cultivating fungal beds.

2. Selection of seed tubers. Select arrow tubers with plump terminal buds, fresh, robust, uninjured, free of pests and diseases, and weighing about 250 g as seed tubers.

3. Planting of seed tubers. Both winter planting and spring planting are acceptable. When planting, place several rows of fungal logs appropriately, place the seed tubers flat with the terminal buds facing upward, with a spacing of 15 cm-20 cm. Generally, winter planting is simple greenhouse cultivation. Choose a wind-sheltered, sunny location; the greenhouse should be built with an east-west orientation, higher in the north and lower in the south, covered with plastic film on top, and with ventilation openings on both sides. Inside the greenhouse, spread sandy loam about 20 cm thick and maintain suitable water content. In winter, plant arrow tubers as they are harvested. After planting, the temperature is required to rise gradually from low to high; generally about 40 days at a low temperature of -1°C-0°C, then gradually rising to 5°C-8°C, 8°C-15°C, and 15°C-24°C, with the growth period maintained at about 25°C, and the relative air humidity maintained at 60%-70%. In April-May, the flowering stalk emerges and blooms. Spring planting is done outdoors; in April-May, plant in conjunction with harvesting, suitably under forest or on wind-sheltered, sunny sandy loam, covering with 5 cm of humus soil. After seedlings emerge, set up supports to fix them and prevent lodging. Build a shade shed, and water during drought.

4. Artificial pollination. Gastrodia elata mainly relies on small soil bees of the genus Halictus for pollination, but there are relatively few small soil bees in nature, so the pollination rate is very low. Therefore, cultivation in courtyards or indoors must use artificial pollination. Generally, this is done around 10 a.m. on the day after flowering. The method is to fix the flower base with the left hand, hold small tweezers with the right hand and gently insert them deep into the flower neck, remove the anther cap with the tweezers, and clip it together with the pollinia onto the sticky stigma at the base of another flower, pressing gently so that the pollen tightly combines with the sticky fluid. When performing artificial pollination, be careful not to puncture the ovary. Gastrodia elata has an indeterminate inflorescence, and the opening time of the basal flowers and the terminal flowers differs by about 10 days-15 days. During artificial pollination, it can be done in stages, and markers should be made to avoid omissions.

5. Fruit harvest. Generally, by late June the seeds mature one after another. Check every day and harvest when the fruit splits; harvest in stages and batches. After harvesting, wrap the fruits in paper and place them in a cool, dry place for 2 days-3 days, then shake out the seeds and sow them.

6. Sowing method. Generally, leaf fungal beds are mostly used for cultivation. In March-April, dig open the cultivated fungal bed, spread sandy loam or humus soil 3 cm-5 cm thick, then place 1 layer of fungal logs with the best Armillaria mellea growth, then spread 1 layer of leaves and press gently to level. Sow with a small cylindrical seeder made from a 120-mesh sieve bottom. After sowing, spread another layer of leaves, then sow the second layer of seeds on top, cover with soil 3 cm-5 cm, cover with 1 layer of leaves, place fungal logs, and finally cover with soil 10 cm-15 cm. For each pit, place 10 fungal logs and sow 5-10 capsules, containing about 200,000-300,000 seeds. Some also adopt a single-layer sowing method; when sowing, leave the fungal logs at the bottom layer of the fungal bed undisturbed, add a thin layer of moist leaves, then sow, put the upper-layer fungal logs back, and cover with soil until level with the ground.