Shiitake Mushroom Spawn Production

Shiitake mushroom spawn production includes three stages: mother spawn cultivation, primary spawn cultivation, and cultivation of spawn. The mother spawn must be a superior strain that has undergone certain fruiting trials and been identified; it is a test-tube spawn, also known as primary spawn. The primary spawn is propagated from the mother spawn and inoculated into sawdust or granular culture medium; it is also known as secondary spawn. The spawn is propagated from the primary spawn by inoculating it into sawdust culture medium to supply large-scale production needs; it is also known as tertiary spawn. Each spawn grower should budget and plan their spawn ordering in advance according to their actual production scale to avoid delaying the production cycle.

 Spawn Isolation
Shiitake mushroom spawn isolation can be achieved through tissue isolation and spore isolation. Spore isolation is generally used for spawn selection, while tissue isolation is more commonly used in production. The specific methods for tissue isolation are described below.

(1) Preparation of Equipment and Culture Medium
Dissecting scalpel or knife, inoculation needle, alcohol lamp, cotton wool, 75% alcohol, and potato dextrose medium.

(2) Selection of Seed Mushrooms: Select seed mushrooms from substrate logs with strong mycelial viability, normal fruiting, and a dominant growth pattern. Choose fresh mushroom fruiting bodies that are large, round, thick-fleshed, with short, thin stems, dark color, unopened caps, conforming to the varietal characteristics, and 6-7 parts mature.

(3) Disinfection of Seed Mushrooms: Remove surface debris, cut off the culture medium portion at the base of the stem, and disinfect the surface of the seed mushrooms with 75% alcohol-soaked cotton. Then, transfer the separation equipment and culture medium into the inoculation box and perform routine disinfection before separation.

(4) Separation of Tissue Blocks: Using disinfected hands, tear the stem in half from the base upwards. Use a sharp knife to cut the tissue block slightly above the junction of the stem and cap. Then, use an inoculation needle or tweezers to transfer the cut tissue block into the slant culture medium, slightly inside the center. (5) Cultivation: Place the test tubes inoculated with the tissue blocks at a constant temperature of 25-27℃. Generally, after 48 hours, the tissue blocks begin to recover, with grayish-white mycelia growing around them and colonizing and spreading onto the culture medium. When the mycelia grow to about 1-2 cm on the culture medium, select test tubes with robust mycelia, cut the mycelia into small pieces using an inoculation tool, and transfer them to a new slant culture medium. After cultivation, these become the mother culture.

(6) Inspection: Quality inspection of the mother culture is a very necessary task. The mother culture obtained by tissue isolation method consists of binucleate mycelia. Under a microscope, each cell of the mycelium has two nuclei, and clamp connections are present at the cell septa. The more clamp connections, the stronger the fruiting ability.

(7) Fruiting Test: The mother culture obtained from tissue isolation must pass a fruiting test to confirm its normality before it can be used on a large scale.