Abstract
pH is an impotant factor for good production of Oyster mushroom. Most of the mushrooms grow and perform well at pH near to neutral or light basic. Lime (CaCO3) is an important constituent in mushroom cultivation, commercial cultivation of mushroom depends upon proper adjustment of pH of substrate. Most of the substrates used for the cultivation of mushroom have pH approximately near to neutral i.e., 7 in Pakistan. In this study, Oyster mushroom (Pleurotus sp.) was grown on cotton waste with different levels of lime in substrate like 0%, 2%, 4% and 6% of substrate weight at pH 7.2, 7.8, 8.2 and 8.7 respectively, to find out the most suitable pH/level of lime for mycelial growth and fructification of mushroom. Data regarding number of days for mycelial growth, number of days taken for initiation of primordia, number of pinheads, number of days taken to reach at harvesting stage after primordia initiation, number of days taken to reach at harvesting stage, total number of fruiting bodies, yield of mushroom in 1st flush (g), yield of mushroom in 2nd flush (g) and total yield of mushroom (g) was recorded. It was observed that treatment containing 2% lime completed mycelial growth after 18 days of inoculation of spawn, number of days taken for initiation of primordia (3 days), number of days taken to reach at harvesting stage after primordia initiation (3 days), number of pinheads (30.8), time taken to reach picking stage after spawning (25 days), yield of mushroom in 1st flush (41.02g), yield of mushroom in 2nd flush (15.3g) and total yield of mushroom was recorded 56.32g and 9.57g on fresh and dry weight basis, respectively. In conclusion use of 2% lime is good for the production of Oyster mushroom (Pleurotus spp.) using cotton waste as a substrate. The Oyster mushroom grows well and give best yield at pH slightly basic in nature.