Influence of light and spawn quantity on the growth of Nigerian mushroom Pleurotus tuber-regium.

The effects of light and quantity of spawn on the sporophore and sclerotial yields of Pleurotus tuber-regium, cultivated on cotton wastes, rice straw, cocoyam peel, comcob, groundnut shell and sawdusts of Mansonia altissima, Khaya ivorensis and Boscia angustifolia were observed. The organism had sporophore and sclerotial yield values of 36.8 and 27.6 g kg(-1) waste, respectively, in cotton waste, at light quantum of 695 lux. There was a highly significant increase in yield of sclerotia (188.0 g kg(-1) waste), in total darkness, while malformed fruitbodies (sporophores) were produced in all the substrates under the same condition. Increasing the quantity of spawn from 5 to 30% reduced the period of spawn run from 13 to 6, 15 to 8 and 24 to 17 days, respectively in P. tuber-regium fruitbodies grown in cotton waste, rice straw and sawdust of B. angustifolia, with yield values of 38.0 and 20.0 g kg(-1) waste in cotton waste and rice straw. The optimal spawn levels forsclerotia formation in the two wastes were 10 and 5%, respectively. The mushroom did not produce sclerotia in corn cob and groundnut shell when exposed to light. However, maximal yield values of 286.8 and 288.4 g kg(-1) waste were obtained in both substrates in total darkness.