Selection and Processing Methods of Seed Tubers for Gastrodia elata

Gastrodia elata tubers that are undamaged, free of pests and diseases, and free of deformities are best for seed cultivation. However, when seeds are in short supply, tubers with minor damage can also be used for seed cultivation after processing. The processing method is: first cut away the damaged part with a knife or bamboo slice, sun-dry the cut surface until it no longer leaks sap, and then plant it; generally it will grow normally.

When large white tubers (baima) are used for seed cultivation, after 1 year they can develop into 1 large arrow tuber (jianma). When arrow tubers are used for asexual propagation as seed, the mixed bud at the tip of the arrow tuber, shaped like a "parrot's beak," must be removed, so that the arrow tuber will not send up a shoot (no longer bolt); this is called "arrow elimination." After arrow elimination, the tuber should be aired for a while so that the part where the bud was removed forms a thin film (no longer exuding nutrient fluid) before it can be planted; otherwise it is prone to rot. After planting, an arrow-eliminated arrow tuber can grow 3-5 large and medium white tubers and a small number of small rice tubers (xiaomima) in 1 year.

Large white tubers can be processed into commercial tubers for medicinal use, but using them as seed for cultivation is not cost-effective. However, some people have adopted the arrow-elimination method used for arrow tubers to conduct bud-elimination experiments on large white tubers (mainly to break apical dominance). The bud-elimination method is the same as the arrow-elimination method for arrow tubers: use a sterilized small knife to cut out the young bud (because the buds of white tubers are small, they cannot be removed by hand). Each time a cut is made, the small knife must be sterilized once, and then the seed tuber body is slightly sun-dried so that the sap exuded from the cut surface dries into a thin film. Once the film has formed, do not continue drying it; bring it back immediately for planting. After planting, many bud eyes on the tuber body can successively sprout more new tubers; some of these grow into arrow tubers, some into white tubers, and some into small tubers. One large white tuber can produce several arrow tubers, white tubers, and many small rice tubers. In the spring 1975 harvest of Dongfeng No. 3 Team, Dishuipu Commune, Ningqiang County, Shaanxi, there was one bud-eliminated white tuber originally weighing 20 grams that grew 8 arrow tubers (weighing 0.925 kg), 7 white tubers (weighing 0.15 kg), and 78 rice tubers all over its body.

The number of arrow tubers and white tubers formed mainly depends on the supply of nutrients from Armillaria mellea and the extent of that supply. If the nutrient supply is sufficient, then more arrow tubers, white tubers, and small rice tubers will grow.