Detailed Explanation of Key Points for High-Yield Cultivation Techniques of the Nameko Mushroom

The nameko mushroom, also known as the slime mushroom or the glistening cap pholiota, is called nameko in Japan. Its scientific name is Pholiota nameko. In botanical classification, it belongs to the kingdom Fungi, subphylum Basidiomycotina, class Basidiomycetes, order Agaricales, family Cortinariaceae, genus Pholiota. It is a rare variety, originally from Japan. Since the mid-1970s, it began to be cultivated in southern Liaoning Province, and the current main production areas are northern Hebei, Liaoning, Heilongjiang, and other places. Since our county began large-scale production in 1989, by using local resource advantages and climatic advantages, and through continuous technological innovation by the broad ranks of scientific and technical personnel, the production volume and quality of the nameko mushroom have been continuously improved. It has now become the leading product of our county's edible mushroom industry. In 2004, the output was 50,000 tons, accounting for 40% of the national output and 25% of the world output. It has become a good project for the broad rural areas of our county to escape poverty and become prosperous.

1. Biological Characteristics

1.1 Nutrition The nameko mushroom is a wood-decay fungus, and in nature it mostly grows on broadleaf trees, especially on the stumps and fallen logs of Fagaceae. For artificial cultivation of the nameko mushroom, agricultural and sideline products rich in lignin, cellulose, hemicellulose, and protein, such as sawdust, straw, rice bran, and wheat bran, are used as artificial cultivation substrate. The nameko mushroom's need for growth factors does not require additional supplementation in commonly used formulas with rice bran and wheat bran as the culture medium.

1.2 Temperature The mycelium of the nameko mushroom can grow between 5°C and 32°C, with the optimum temperature being 22°C to 25°C. The fruiting body can grow between 5°C and 18°C; above 20°C, the fruiting body cap is thin, the stipe is slender, and the cap opens early; below 5°C, growth is slow and basically does not occur.

1.3 Light Nameko mushroom cultivation does not require direct light, but there must be sufficient scattered light. The mycelium can grow normally in a dark environment, but light has the effect of inducing fruiting in physiologically mature nameko mushroom mycelium. During the fruiting stage, a certain amount of scattered light should be provided. If the light is too dim, the cap color is pale, the stipe is slender, the quality is poor, and the yield will also be affected.

1.4 Humidity The water content of the mycelium culture substrate is preferably 60% to 65%. During the fruiting body formation stage, the water content of the culture substrate is best at 75% to 80%, and the relative air humidity is required to be 85% to 95%.

1.5 Air The nameko mushroom is also an aerobic fungus, and its oxygen demand is related to respiratory intensity. In early spring, at the beginning of inoculation, the temperature is low, the mycelium grows slowly, and a small amount of oxygen can meet the need; as the temperature rises, mycelial metabolism accelerates, respiration increases, and mycelial mass increases, so attention must be paid to ventilation of the mushroom house and air exchange inside and outside the substrate bags. During the fruiting stage, the metabolism of the fruiting body is very vigorous and fresh air is even more needed. If the carbon dioxide concentration in the environment exceeds 1%, the fruiting body cap is small, the stipe is slender, and the cap opens early.

1.6 pH The pH of the culture substrate directly affects the activity of cellular enzymes. The mycelial growth of the nameko mushroom requires a pH value of 5 to 6. The culture substrate made from sawdust, wheat bran, and rice bran generally has a pH of 6 to 7, but after heating and sterilization the pH value will decrease, so there is no need to adjust the pH value again.

2. High-Yield Cultivation Techniques

2.1 Cultivation Season The nameko mushroom is a low-temperature, temperature-variable fruiting type fungus. In northern China, spring planting and autumn fruiting is generally adopted. Semi-cooked substrate cultivation is suitable, and it is best to choose the early spring season when the temperature is below 8°C. The best sowing period is mid-February to mid-March.

2.2 Selection of Excellent Spawn

(1) Variety Selection According to differences in fruiting temperature, nameko mushrooms are divided into very early-fruiting varieties (optimum fruiting temperature 7°C to 20°C), early-fruiting varieties (5°C to 15°C), medium-fruiting varieties (7°C to 12°C), and late-fruiting varieties (5°C to 10°C). Producers should select excellent varieties according to local climate, cultivation method, and purpose. At present, the main cultivated varieties in the main production areas mainly include Zaofeng 112, C3-1, and others.

(2) Spawn Selection When selecting spawn, it is required that it is not degenerated and not mixed. Externally, the mycelium should be white, fluffy, dense, uniform, and robust; the spawn age is required to be 50-60 days, not aged, not shriveled, and with no water accumulation. When selecting spawn, varieties should be used in combination and not a single variety alone, to prevent fruiting from being too concentrated and affecting product @#@136@#@.

2.3 Construction of the Nameko Mushroom Fruiting Shed A good cultivation site is the basic condition for the normal growth and development of the nameko mushroom. Under the current production level and economic conditions in rural areas, idle residential houses and sheds are generally used as mushroom houses in a makeshift way, and some also cultivate nameko mushrooms in air-raid shelters, mountain caves, and other places, and most adopt dual use of one site, that is, both a mycelium culture room and a fruiting room for the growth and development of fruiting bodies.

Standardized production now generally uses louver-type fruiting sheds. The shed height is 3.5 m. The cultivation racks in the shed can be built in layers with wooden poles or bamboo poles. Generally, the rack height is 1.7 m to 1.8 m, the width is 0.6 m, the bottom layer is 0.2 m from the ground, and the spacing between layers is 0.3 m to 0.4 m. Seven layers are suitable, with a 0.8 m aisle left in the middle. A structure using cement as upright posts and four No. 8 iron wires stretched as horizontal bars can also be used.

2.4 Commonly Used Formulas (1) Sawdust 77%, wheat bran (or rice bran) 20%, gypsum 2%, superphosphate 1%, pH 6.0-6.5, water content 60%-65%.

(2) Currently promoted formula: sawdust 84%, wheat bran or rice bran 12%, cornmeal 2.5%, gypsum 1%, lime 0.5%, pH 6.0-6.5, water content 60%-65%.

2.5 Mixing Materials Weigh the culture substrate according to the proportions, mix evenly, and add water according to the dryness or wetness of the raw materials so that the water content reaches 60%-65%, then pile and let stand for 30 minutes.

2.6 Sterilization (1) Use bulk material sterilization with a steam type (aerated boiler) and layer-by-layer material scattering sterilization method. First, spread a layer of burlap on the steamer tray to prevent material from leaking. After the steam rises, spread the culture substrate evenly on the steamer tray to a thickness of about 6 cm to 8 cm (do not pat or press it with hands or shovels). When strong steam rises, use a shovel to scatter the material in layers, ensuring even scattering, and press down the steam. Load layer by layer in this way, filling to 8 parts full, that is, loading the material surface to 20 cm from the upper opening. Cover and press firmly, then heat intensely with a strong fire until reaching 100°C, maintain for 2 hours, then let stand for 30 to 40 minutes, and it can be removed from the pot while hot. Sterilization must be thorough. Each pot is suitable for sterilizing 200-500 trays (note: when coarse sawdust is used as the main material, the sterilization time should be extended).