High-Quality, High-Yield Cultivation Techniques for the New Edible Mushroom Variety Pholiota adiposa
Pholiota adiposa (Fr.) Quél., also known as yellow mushroom, fat scalycap, willow mushroom, etc., belongs to the phylum Fungi, class Basidiomycetes, order Agaricales, family Strophariaceae. It generally occurs in August to October, when temperatures gradually drop and the temperature difference is large, growing on the trunks of poplar, willow and birch, and sometimes also on coniferous trees, solitary to clustered, mostly clustered. The yellow fruiting body is bright in color, golden yellow, with thick flesh, crisp and tender texture, and delicious flavor. It is a rare edible mushroom used both as food and medicine. Its cap surface has a layer of slimy substance, reported to be nucleic acid substances, which can enhance human immunity and inhibit tumors, with an inhibition rate of 80%-90% against mouse sarcoma S-180 and Ehrlich ascites carcinoma, and can also prevent infection by Staphylococcus, Escherichia coli, Klebsiella pneumoniae and Mycobacterium tuberculosis.
In recent years, with the continuous improvement of people's living standards, the enhancement of self-health-care awareness and the continuous improvement of understanding of the value of edible mushrooms, people's attention to the selection of edible mushroom species and the entire process of edible mushroom production, processing and consumption has been increasing day by day. With its superior quality and extremely high health-care value, Pholiota adiposa will gradually become a new favorite for consumers, with great development potential. In recent years, the Edible Mushroom Research and Development Center of the Chinese Academy of Agricultural Sciences has obtained pure strains through field collection, isolation and culture, and through domestication culture and cultivation experiments, has preliminarily explored the biological characteristics of Pholiota adiposa and high-quality, high-yield cultivation techniques for Pholiota adiposa.
I. Morphological Characteristics
1. Mycelium morphology. The mycelium is thick and strong, and the colony is felt-like, dense, white, and secretes pale yellow to orange-yellow pigment in the later stage, with the mycelium at the front forming rhizomorph-like structures.
2. Fruiting body morphology. The fruiting body is solitary or gregarious, with a cap 3-14 cm; initially flat hemispherical, with the margin inrolled, later gradually flattening, valley yellow to light withered-leaf color; sticky and slippery when the surface is moist, with yellow-brown appressed scales or white scales. The flesh is white to pale yellow. The gills are pale yellow to rusty brown, adnate or nearly sinuate, somewhat crowded. The stipe is thick and strong, fibrous, 5-12 cm long, 1-3 cm in diameter, solid, yellow above and brown below, with small scales. The annulus is pale yellow, membranous, borne on the upper part of the stipe, easily falling off. The gills are adnate, somewhat crowded, yellow to rusty brown. At maturity, a large number of rusty-colored spores are released; the spores are elliptical, smooth, 7.5 μm-10 μm × 5 μm-6.5 μm in diameter.
II. Biological Characteristics of Pholiota adiposa
1. Nutrition. Pholiota adiposa is a wood-rotting fungus. Lignin and cellulose are the main nutrients, glucose is a good carbon source, yeast powder is a good nitrogen source, and growth on inorganic nitrogen is poor. Both the mycelial growth and fruiting body development stages require the participation of inorganic elements and vitamins. Sawdust contains relatively few trace elements, so during the fruiting period some trace elements should be appropriately supplemented, such as phosphorus, potassium, manganese, zinc, copper, magnesium and other trace elements, at a content of 0.01%-0.2%. In production, cottonseed hulls, mixed sawdust, willow sawdust, corncobs and wheat bran can be used as the main raw materials for artificial cultivation.
2. Temperature. Pholiota adiposa is a medium-low temperature fungus. The mycelial growth temperature is 8-32°C, with the optimum temperature being 20-25°C. The fruiting body growth temperature is 12-25°C. The optimum temperature is 15-20°C. During the fruiting body differentiation period, stimulation by a temperature difference of 5-10°C is needed, so cultivation in early spring and late autumn is relatively easy for the formation and growth of the fruiting bodies.
3. Humidity. During the spawn-running period, the moisture content of the culture medium is suitably controlled at 60%-65%. When mixing the substrate, the material-to-water ratio is controlled at about 1:1.2, and during the fruiting period the air humidity of the mushroom house is adjusted to 85%-90%.
4. Air. Pholiota adiposa requires oxygen supply during both the mycelial growth stage and the fruiting body formation stage. During the spawn-running period, ventilation holes need to be left at the inoculation openings; during the fruiting period, the mushroom house needs daily ventilation and air exchange, otherwise the stipe elongates and the cap becomes thin, small and deformed. However, before opening the bag, the carbon dioxide concentration inside the bag can stimulate primordium formation; after the primordium forms, the bag is then opened for fruiting, and the fruiting bodies form relatively quickly.
5. Light. Mycelial growth can proceed in darkness, but during the primordium formation stage, induction by scattered light is needed, and appropriate scattered light is also needed in the fruiting house.
6. pH. Pholiota adiposa can grow well in a slightly acidic environment. The suitable pH range is 4-7, with pH 5.5-6.5 being relatively suitable.
III. Spawn Culture of Pholiota adiposa
1. Preparation of mother culture. Mother culture medium: potato 200 g, glucose 20 g, malt extract 2 g, magnesium sulfate 0.2 g, monopotassium phosphate 0.25 g, dipotassium phosphate 0.25 g, VB1 0.5 mg, agar powder 15 g, water 1000 ml, pH natural.
The time for the mycelium in test tube culture to grow over the slant is generally about 10 days.
2. Culture of stock spawn and cultivation spawn. For stock spawn and cultivation spawn, wheat grain spawn or cottonseed hulls can be used as the main raw material.
Preparation of wheat grain spawn medium: before use, soak the wheat grains in clean water for 12 hours, boil the soaked wheat grains in boiling water at 100°C for 20-30 minutes, until the seed coat does not break and there is no white core inside the grain. When the temperature drops to 30-40°C, add 1%-2% gypsum and lime, mix well and bag.
Preparation of cottonseed hull medium: the raw material formula is cottonseed hulls 78%, wheat bran 20%, gypsum 1%, lime 1%, or cottonseed hulls 75%, wheat bran 20%, lime 1%, gypsum 1%, sucrose 2%, urea 1%. Sterilization method: a small autoclave is kept at a pressure of 1.4 kg/sq cm and sterilized for 60 minutes; or a large autoclave is kept at a pressure of 1.2 kg/sq cm and sterilized for 120 minutes.
Culture of stock spawn and cultivation spawn: control the temperature at 23-25°C. At a suitable temperature, the mycelium grows quickly, robustly and evenly, which is beneficial for cultivation and fruiting. After the mycelium has fully grown, it should be used as soon as possible. Generally, the storage period at room temperature does not exceed 7 days, and low-temperature storage does not exceed 15 days. Overdue spawn cannot be used as cultivation spawn.