Spawn is sterilised grain that a laboratory has grown mushroom mycelium through. It is not seed. Nothing crosses or pollinates on your farm, so every mushroom in the bag is a copy of the strain the lab supplied.
Strain choice therefore travels with the spawn. The NHB model report lists Indian strains from 14 to 16 kg per 100 kg compost up to 22 to 27 kg for DMR-NBS-5, measured with spawn run near 24 °C and fruiting near 15 °C. Buy from a recognised laboratory and note the strain and lot number.