How to best select Gastrodia elata tubers for use as seed
Gastrodia elata tubers that are undamaged, free of pests and diseases, and free of deformities are best for cultivation as seed. However, when seed is in short supply, tubers with minor damage can also be treated and used for cultivation as seed. The treatment method is: first cut away the damaged part with a knife or bamboo slice, sun-dry the cut surface until it no longer bleeds sap, then plant, and generally they will grow as normal.
When large white Gastrodia tubers are cultivated as seed, after 1 year they can become 1 large arrow Gastrodia tuber. When arrow Gastrodia tubers are cultivated as seed for asexual propagation, the mixed bud at the tip of the arrow tuber that looks like a "parrot's beak" must be pinched off, so that the arrow tuber will not produce an arrow (no longer send up a stem), which is called "extinguishing the arrow." After extinguishing the arrow, let it air for a while so that the part where the bud was removed can form a thin film (no longer exuding nutrient solution), and only then can it be planted, otherwise it easily rots. Arrow-removed arrow tubers can, 1 year after planting, grow 3-5 large and medium white tubers and a small number of millet-sized tubers.
Large white Gastrodia tubers can be processed into commercial Gastrodia tubers for medicinal use, while cultivating them as seed is not cost-effective, but some people have also used the arrow-extinguishing method for arrow tubers to conduct bud-extinguishing experiments on large white tubers (mainly to break apical dominance). The bud-extinguishing method is the same as the arrow-extinguishing method for arrow tubers, using a sterilized knife to carve out the young bud (because the buds of white tubers are small and cannot be pinched off by hand). Each time a cut is made, the knife is sterilized once, then the seed tuber body is lightly sun-dried so that the sap seeping from the cut area dries into a thin film. Once the thin film has formed, do not continue drying it in the sun; bring it back immediately and plant it. After planting, many bud eyes on the tuber body can successively sprout more new tubers; some of these tubers 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 millet-sized tubers. In the spring 1975 harvest by Dongfeng Team 3 of Dishuipu Commune, Ningqiang County, Shaanxi, there was one bud-extinguished white tuber originally weighing 20 grams that grew all around 8 arrow tubers (weighing 0.925 kg), 7 white tubers (weighing 0.15 kg), and 78 millet-sized tubers.
The number of arrow tubers and white tubers formed depends mainly on the supply and extent of nutrients provided by Armillaria mellea; if the nutrient supply is sufficient, then more arrow tubers, white tubers, and millet-sized tubers will grow.