How to make high-quality mushroom strains? High-quality shiitake mushroom strains are a strong guarantee for high yields and high economic benefits. The preparation of bacterial strains can go through the processes of pure strain isolation and testing→preparation of mother strains→preparation of original strains→preparation of cultivated species→strain preservation. 1. Pure breed separation and mushroom test: Select mushrooms that have early fruiting, uniform fruiting, clusters, good flower shape, thick and fat, short stalks, good color, and 80% mature mushrooms as seed mushrooms. Use the spore isolation method, tissue isolation method or mushroom wood isolation method, use potato dextrose agar or cornmeal agar culture medium for pure species isolation, culture it in an environment of 22-26 degrees Celsius, and grow into colonies in 10-20 days. Pick out white-colored colonies. , strong, disease-free and pest-free mycelium is transferred to the slant for culture. After 2-3 times of pure culture and fruiting test, excellent strains are selected as mother seeds. 2. Preparation of mother seeds: Take the pure seeds that have passed the mushroom fruiting test and culture them with potato dextrose agar at 24-26 degrees Celsius. The mother seed can be transferred to 3-4 generations for expansion. 3. Preparation of original seeds: Expand the culture of the mother seeds in a culture medium close to the cultivation material to obtain the original seeds. The original seeds can also be used directly for cultivation and inoculation. Original culture medium: 78% sawdust, 20% rice bran or bran, 1% sucrose, 1% calcium sulfate, and appropriate amount of water. Put it into a 750 ml strain bottle, wrap it up and sterilize it under 1.5 kg pressure for 1 hour. After inserting the mother seed, culture it at 24-26 degrees Celsius for 30-40 days until the mycelium fills the bottle. 4. Preparation of cultivated seeds: Cultivated seeds are further expanded production of the original seeds and are directly used for cultivation and inoculation. The medium formula and culture conditions are the same as those of the original seeds. Wood blocks can also be used as culture media. Use 1,000 round wood particles or wedge-shaped wood blocks with a thickness of 1.5-1.8 cm and a diameter of 1 cm, 100 grams of sawdust, 50 grams of rice bran, and 150-200 ml of water. First soak the wood pellets in water, then mix with the water soaked in the wood pellets, then put it into a strain bottle, sterilize it under 1.5 kg pressure for 1 hour, and then inoculate and culture it. 5. Strain requirements: Shiitake mushroom mycelium is white, part of it grows into the material, part of it is aerial, and the appearance is elastic. Mycelial agglomeration is good, and the surface of mature mycelium turns into dark brown, has the special smell of shiitake mushrooms, is free from diseases and insect pests, and is strong. When the strain grows to 1/3 of the bottle, the temperature in the culture room can be lowered by 2-3 degrees Celsius to facilitate the growth of the strain. Mature strains should be stored in a cool, dry and clean environment to prevent contamination and slow down growth, and avoid accelerated aging.