What methods are there for identifying the quality of edible mushroom spawn?

Many edible mushroom growers often report that the use of poor-quality spawn leads to cultivation failure, yet they do not know how to tell good spawn from bad. For this reason, the author specifically introduces several simple methods for identifying good and poor edible mushroom spawn. 1. Oyster mushroom. Spawn with white, dense, thick mycelium, appearing cottony-woolly, and showing the phenomenon of climbing the bottle wall is good spawn. If spawn cultivated on sawdust is used, sawdust that has been decomposed takes on a light yellow color, and a small number of primordia appear, it is good spawn. If the mycelium is sparse or forms strands, the cottonseed hull substrate turns dark red, the sawdust substrate turns white, the mycelium pulls away from the bottle wall and shrinks, yellow fluid accumulates at the base of the bottle, or mold spots appear on the surface of the substrate, it is all poor-quality spawn. 2. Wood ear. Spawn with white, thick, neat, and uniform mycelium is good spawn. If the mycelium is sparse and particles of the substrate can be seen; if primordia appear before the mycelium has filled the bottle; if light yellow fluid accumulates at the base of the bottle, it is all poor-quality spawn. 3. Enoki mushroom. Spawn with white, thick mycelium, or with a fine powdery appearance, strong vitality, and later forming fruiting bodies in clusters on the substrate, is good spawn. If the mycelium cannot grow deep downward and shows the phenomenon of exuding yellow water, it is aged spawn and cannot be used. 4. Shiitake. Spawn with white, cottony-woolly mycelium, uniform growth, no thick mycelial mat, and easy formation of primordia is good spawn. If the mycelium in the bottle is sparse, the mycelium pulls away from the wall, shrinks, and the mycelial mat turns brown, it is degenerated spawn or aged spawn. 5. Straw mushroom. Spawn with white, transparent mycelium is young spawn; spawn with yellow-white or gray-white, transparent mycelium is spawn of suitable age; spawn with mycelium so dense it forms a mycelial mat and with the upper layer of mycelium shrinking is old spawn. Spawn that is too young or too old cannot be used for cultivation. 6. Button mushroom. Spawn with gray-white mycelium, slightly tinged with blue, in fine threads, and without a yellow-white mycelial mat is good spawn. Spawn with light yellow, shrunken mycelium, or with an overly thick mycelial mat in the upper part of the bottle, is poor-quality spawn. 7. Lion's mane mushroom. Spawn with white, thick mycelium distributed evenly from top to bottom, easily forming fruiting bodies on the surface of the substrate, with thick-fleshed fruiting bodies and long spines, is good spawn. Spawn with sparse, fine, unevenly distributed mycelium, or with primordia appearing before the mycelium has grown halfway, or with the bottom of the bottle filled with yellow viscous liquid, is all poor-quality spawn.