Preliminary Report on the Results of Substrate Replacement Cultivation Trials of Gastrodia elata

Artificial cultivation of Gastrodia elata mainly uses the trunks of broadleaf trees such as oak, birch, hazel, elm, willow, jujube, pagoda tree, and wild cherry, and requires a diameter of more than 5 cm. For a long time, this has caused severe damage to forest resources, which are now on the verge of exhaustion. Therefore, research on substrate replacement cultivation techniques for Gastrodia elata has gradually become a hot topic. There are already precedents for substrate replacement cultivation using corn cobs, shrub stems, corn cobs, corn pith, branches, and straw, but no reports on the cultivation of Gastrodia elata with cottonseed hulls have been seen. For this reason, this trial was conducted, and the preliminary results are reported as follows:

1 Materials and Methods

1.1 Test materials ① Armillaria mellea was purchased from the Gastrodia elata Research Institute of Yang County, Shaanxi. ② Seed tubers were purchased from the Edible Fungi Research Institute of Xixiang County, Shaanxi, and were first-generation small tubers. Cultivation of Armillaria mellea spawn: the stock culture medium was a comprehensive PDA slant, sterilized by conventional autoclaving. After inoculation, it was cultured at 28°C for 10 d. The mother spawn medium was: 3 parts broadleaf tree sawdust, 1 part wheat bran, and an appropriate amount of short apple branch sticks (1-2 cm thick, 2-3 cm long, soaked in 0.25% ammonium nitrate for 24 h). The water content was 70%. It was bottled and sterilized by conventional autoclaving. After inoculation, it was cultured at 28°C for 30-40 d.

1.2 Test formulas A total of 7 treatments were set up in this trial, as shown in Table 1. In addition, each was supplemented with 1% white sugar, 1% gypsum powder, and 0.1% special disinfectant. The water content was controlled at 70%.

Table 1 Substrate formulas tested (%)

Formula Cottonseed hull Wheat bran Apple branch Potato

　　185155

2401540 (short sticks*) 5

3301550 (short sticks*) 5

4201560 (short sticks*) 5

5401540 (long branches**) 5

6301550 (long branches**) 5

7201560 (long branches**) 5

Note: * 1-2 cm thick, 2-3 cm long, soaked in 0.25% ammonium nitrate for 24 h. ** 1-2 cm thick, length based on being able to lie flat in the box, soaked in 0.25% ammonium nitrate for 24 h.

1.3 Cultivation and management methods Potato tubers were boiled, mashed into a paste, diluted with water, and sugar, gypsum, and disinfectant were added. After dissolution, cottonseed hulls and wheat bran were mixed in and stirred evenly for later use. Indoor box cultivation was used. The wooden boxes were enclosed around the sides with plastic film. A 10 cm layer of substrate was spread flat on the bottom of the box, a layer of Armillaria mellea spawn was scattered on top, 1 Gastrodia elata seed tuber was sown every 10 cm, then another layer of substrate was spread, then another layer of spawn and Gastrodia elata was sown, and then 10 cm of substrate was covered, with a layer of plastic film on top. Daily management: spray water frequently to keep it moist, pay attention to aeration and pest prevention. In midsummer, keep the indoor temperature below 28°C.

1.4 Trial time Sowing was on March 20, and harvest was on November 20.

2 Results and Analysis

As can be seen from Table 2, the yields of formulas 3, 4, and 6 were higher than those of the other treatments and relatively close to one another, while formula 1 was the worst. This indicates that the content of apple branches in the substrate plays an important role. Using only cottonseed hulls may provide insufficient nutrition, so the Gastrodia elata was smaller and the yield was extremely low. With an increase in the proportion of apple branches, the yield of Gastrodia elata was extremely low. However, when the proportion was too high, the yield fell again. The reason may be that the branches combine loosely and the hyphae do not easily spread. The optimal amount of apple branches was 50%. The length of the apple branches had little effect on yield, and long branches can be used in production. This can save labor, because processing short sticks is quite time-consuming and labor-intensive.

Table 2 Harvest yield of Gastrodia elata under each formula

Formula 1234567

Seed tuber weight 4.54.54.54.54.54.54.5

Harvest yield 19346660315950

Weight of the largest one 9132823112421

Note: The data in the table are the average weight of three replicates, in g.

3 Discussion

From the trial results, it is feasible to cultivate Gastrodia elata with cottonseed hulls and apple branches. ① It can alleviate the shortage of wooden sticks (fungus wood), change the situation of reckless deforestation, and protect forest resources and the ecological environment. ② It opens up a new way for utilizing the byproducts of the cotton and fruit industries, turning waste into treasure and increasing farmers' income.

It should be pointed out that many problems in this technique remain to be solved. For example, the optimal formula, the Armillaria mellea strains suitable for cotton and fruit production areas (northern China), and Gastrodia elata varieties still need further selection, and outdoor cultivation conditions still need to be explored. In addition, cottonseed hulls carry a relatively large microbial load, and because aseptic operation cannot be carried out during sowing, contamination is relatively likely. We have already screened a special disinfectant that inhibits contaminating microbes without affecting the growth of Armillaria mellea, and it is currently undergoing further verification.