Detailed Explanation of the Low-Altitude Substitute-Material Cultivation Method for Gastrodia elata (Part One)
Gastrodia elata is a rare and precious traditional Chinese medicine. In the past it was gathered from the wild, growing in mountain forests above 500 m in altitude, and was very scarce and difficult to dig up; today it faces extinction. The development of artificial cultivation of Gastrodia elata has saved this precious species, but technically it still cannot break away from cultivation in high-altitude areas, and the raw material cannot be separated from log segments (oak). This makes Gastrodia elata cultivation greatly limited by region. Second, it is limited by the felling of forest resources. These two major drawbacks have long plagued the development of Gastrodia elata, and it has never been possible to achieve modernized, standardized cultivation of Gastrodia elata.
This method addresses the above-mentioned shortcomings of existing technology. Through long-term research and experimentation, we have worked out a new cultivation method for Gastrodia elata that is not limited by regional altitude or raw materials. In areas below 300 m in altitude, it can use straw and corn cobs to cultivate Armillaria mellea and grow high-yield, high-quality Gastrodia elata. Through improvements in elite variety selection and breeding, cultivation environment, cultivation raw materials, culture medium formula, and cultivation methods, low-altitude substitute-material cultivation of Gastrodia elata has been achieved. The specific contents are introduced as follows:
I. Raw material selection and treatment
To cultivate Gastrodia elata, Armillaria mellea must first be well cultivated. In the past, log segments (oak species) were mainly used to cultivate Armillaria mellea. With the protection of ecological balance, the state prohibits the felling of forests, so the raw materials for cultivating Armillaria mellea with log segments have been affected. In order to find a way out, we conducted experiments with straw, and after repeated exploration and practice it was proved that whole corn cobs are the ideal material for cultivating Armillaria mellea.
The materials used to cultivate Armillaria mellea with substitute materials have certain special requirements. Corn cobs can be used either dry or fresh, but whole kernels free of mold and rot are preferred. If fresh corn cobs cannot be used in time, they must be spread out under the sun and fully dried before they can be stored. Otherwise, with moisture present they will become moldy during storage. In particular, green mold and yellow mold occur very easily and will affect the growth of Armillaria mellea in the future. If any moldy ones are found, they must be picked out, or quicklime water can be sprayed on them, or they can be soaked to eliminate the mold. However, when used, they must be rinsed with clean water to avoid excessively high alkalinity affecting the growth of Armillaria mellea.
II. Selection of Gastrodia elata seed
The quality of Gastrodia elata seed is very closely related to Gastrodia elata yield. There are two sources of Gastrodia elata seed: one is sexual reproduction; that is, after Gastrodia elata completes its physiology, it bolts, flowers, and sets seed, producing pollen seed, or pollen seed after artificial cross-pollination. After 3 to 5 months of cultivation with germination-promoting fungi and Armillaria mellea, pollen seed can be dug out as first-generation seed the size of a peanut kernel, called "zero-generation seed," also known as sexually reproduced hybrid seed. This variety is conducive to high and stable yields of Gastrodia elata. In particular, after distant hybridization between wild black-stem and red-stem Gastrodia elata, the selected "TC828 variety" has become the current first-choice high-yield variety for cultivating Gastrodia elata.
The other is vegetatively propagated Gastrodia elata seed, which is the small Gastrodia elata seed that appears each time Gastrodia elata is dug up. This small Gastrodia elata is cultivated again and after one year becomes commercial Gastrodia elata. The continuous cyclic cultivation of small Gastrodia elata is called a vegetatively propagated variety. However, after 3 to 4 years of vegetative propagation, degeneration readily occurs. Whether degeneration is fast or slow is related to environmental conditions and technology. In order to achieve high quality and high yield of Gastrodia elata, it is best to choose sexually hybridized Gastrodia elata seed.
III. Selection of cultivation site
In the past, Gastrodia elata generally grew in mountain forests at 500 to 1500 m in altitude, with areas at 800 to 1200 m being more suitable. Later, artificial cultivation also chose these high-altitude mountain forests. The main reason is that Gastrodia elata is a medium- and low-temperature variety and is afraid of high temperatures. To solve this difficult problem, in addition to selecting and breeding Gastrodia elata seed and domesticating varieties with higher temperature adaptability, the key is to adopt corresponding coordinated measures in the selection of the cultivation site and in artificial cooling, so that cultivation of Gastrodia elata in low-altitude areas can be fully realized.
Low altitude refers to plain areas below 300 m. Cultivation can be carried out in cool indoor environments, outdoors under forest, under artificial shade sheds, and similar environments. A place should be chosen that both avoids direct sun exposure and prevents washing by floods; preferably it is a shady, moist slope with good drainage. In terms of environment, it is best to have large areas of natural shade forest or artificial shade forest. As for soil quality, fertile, relatively loose, air-permeable soil that does not easily harden is preferable. Sandy soil or humus soil may also be used. The soil moisture content should be between 50% and 60%. The suitable soil moisture is such that when squeezed in the hand the soil forms a ball and disperses as soon as it is dropped. Clay or hardened soil is generally not suitable.
IV. Cultivation of Armillaria mellea
There are many kinds of Armillaria mellea. Not all Armillaria mellea are suitable for the growth of Gastrodia elata, and not all those that can suit the growth of Gastrodia elata are excellent Armillaria mellea varieties. Armillaria mellea also differ in quality, and only high-quality Armillaria mellea can grow together with Gastrodia elata with complementary nutrition. At present, from among several Armillaria mellea varieties, the excellent Armillaria mellea variety "XB-9" has been selected. It is most compatible with the excellent Gastrodia elata variety "TC828" and is the basis for high-yield cultivation of Gastrodia elata at low altitude.
Cultivating Armillaria mellea with corn cobs has the advantages of abundant raw material sources, low cost, fast growth, and good results. The shortcoming is that it can only be used for one year and must be replaced every year, unlike log-segment Armillaria mellea, which can be used for 2 to 3 years. The method for cultivating Armillaria mellea with corn cobs is: first soak the corn cobs in water for 12 to 24 hours (they must be soaked through), then take them out and drain off the excess water. First spread a layer of corn cobs on the ground, about 10 cm thick, and sprinkle on Armillaria mellea mother culture, using 750 g/bottle per square meter. Then spread a second layer of corn cobs, sprinkle on Armillaria mellea culture again, and continue in the same way for a third or fourth layer. Then cover with soil 10 to 15 cm deep and let the fungus grow. Another method is: after spreading each layer of corn cobs and sprinkling on Armillaria mellea culture, fill the gaps between the corn cobs with fine soil, then spread a second layer of corn cobs, sprinkle on Armillaria mellea culture, and fill the gaps between the corn cobs with fine soil. Generally no more than four layers.