PREPARATION OF MOTHER SPAWN
Mother spawn is nothing but the mushroom fungus grown on a grain based medium. Among the several substrate materials tested by TNAU, Coimbatore, sorghum grains are the best substrate for excellent growth of the fungus. Disease- free sorghum grains are used as substrate for growing the spawn materials. The various steps involving in preparation of mother spawn are listed.
- Soak the sorghum grains in clean water to remove chaffy and damaged grains.
- Cook the grains in a vessel for 30 minutes just to soften them.
- Take out the cooked grains and spread evenly on the platform to remove excess water.
- At 50% moisture level mix calcium carbonate (CaCO3) thoroughly with the cooked, dried grains @ 20 g / Kg .
- Fill the grains in saline bottles up to 3/4th height (approximately 300-330 g / bottle), insert a PVC ring , bold the edges of the bag down and plug the mouth tightly with non-absorbent cotton wool.
- Cover the cotton plug with a piece of waste paper and tie tightly around the neck with a jute thread.
- Arrange the bags inside an autoclave and sterilize under 20-lbs. pressure for 2 hours.
- Take out the bags after cooling and keep them inside the culture room and put on the UV light.
- After 20 minutes put off the UV light and start working in the culture room.
Cut the fungal culture into two equal halves using a inoculation needle and transfer one half portion to the bottle. Similarly, transfer another half portion of the culture to another bottle.
- Incubate the inoculated bottle, in a clean room under room temperature for 10 days. This can be used for bed spawn preparation.
Note: The purpose of mixing calcium carbonate is i) to remove the excess moisture present in the cooked grains, ii) to neutralize the pH of the grains and iii) to avoid caking of grains after sterilization.
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