Spawn And Its Production
• Spawn is the planting material for the cultivated mushroom.
• It is merely the vegetative mycelium from a selected mushroom strain grown in a convenient medium.
• The particular strain of mushroom selected decides the type of mushroom the spawn would produce.
Mother Spawn/ Master spawn
The commonly followed method in India is as given below:
Ten kg of wheat or sorghum grains are boiled in 15 litres water. Water is drained off over a wire netting to dry slightly. 120 g gypsum and 30 g lime (CaCO3) are mixed with 10 kg of boiled grains. The gypsum prevents the sticking of grains together as clump and lime adjusts the pH. The grains are then filled into a half litre milk or glucose bottle container upto three-fourth the capacity.
Bottles are plugged with non-absorbent cotton plug and are to be sterilized at 20-22 lb. psi (1260 C) for 1 ½ to 2 hours. Sterilized bottles are taken out from the autoclave while still hot and are shaken to avoid clump formation. The bottles are immediately transferred to inoculating room or chamber and allowed to cool down overnight.
On the following day, bottles are inoculated with two bits of agar medium colonized with the mycelium of pure cultures raised either by tissue or spore by putting the culture bits just opposite to each other in the inner side of glass surface in the middle of the bottle. About 7-10 days after inoculation, bottles are to be shaken vigorously so that mycelial threads are broken and mixed with grains evenly. Three weeks after incubation, the stock culture becomes ready for further multiplication of spawn. One bottle of stock culture is sufficient to multiply in 30-40 polypropylene bags or bottles. Inoculated bottles are incubated at ambient temperature.
The technique for raising commercial spawn is essentially the same as for master spawn except that instead of glass bottles, polypropylene bags can be used as the containers for filling grains. Inoculated bottles or polypropylene bags are incubated at ambient temperature. In two to three weeks after inoculation, spawn becomes ready for seeding the compost.
Boiled with water (1:1.5 w/v)
Drain off excess water
12g/kg grains CaSO4 and 3g/kg grains CaCO3
Filled in bottle
Sterilized at 22psi for 90 minutes
Inoculation with pure culture
Qualities of a good spawn
• The spawn should be fast growing in the compost
• It should give early cropping after casing
• It should be high yielding
• It should produce better quality of mushroom