Influence of substrate formulation on some morphometric characters and biological efficiency of Pleurotus ostreatus EM-1 (Ex. Fr) Kummer grown on rice wastes and "wawa" ( Triplochiton scleroxylon ) sawdust in Ghana.

A study was conducted to correlate the stipe length, cap diameter, and growth yield (fresh weight) of the fruiting body of Pleurotus ostreatus strain EM-1 using different rice lignocellulosic wastes and "wawa" ( Triplochiton scleroxylon ) compost: raw unamended rice straw; rice straw amended with 1% CaCO 3 and 10% CaCO 3 ; rice straw amended with 1% CaCO 3 and 10% CaCO 3 supplemented with 5, 10, and 15% rice bran prior to bagging; rice straw and rice husk mixture (1:1 w/w) amended with 1% CaCO 3 and 10% CaCO 3 supplemented with 5%-15% rice bran prior to bagging; and wawa sawdust amended with 1% CaCO 3 and 10% rice bran. The experiment was laid out in a completely randomized design in a well-ventilated semi-dark room at 26-28°C and 60%-65% ERH. The fresh weight, length of the stipe, and cap diameter increased differentially in each treatment with an increasing period of composting in the substrates. There was a good coefficient of determination ( R 2 ) among stipe length, cap diameter, and biological efficiency (%). The R 2 among stipe length, cap diameter, and biological efficiency for the different formulated substrates ranged between R 2  = 0.6346-0.9454 and R 2  = 0.570-0.9624, respectively. The highest R 2 was obtained on raw unamended rice straw substrates (stipe length and cap diameter were R 2  = 0.9454 and R 2  = 0.9444, respectively), whereas the lowest correlation coefficient among stipe length, cap diameter, and biological efficiency (%) ( R 2  = 0.6346; R 2  = 0.0570), respectively, was recorded on the rice straw and rice husk mixture substrates. The results show a positive correlation in morphometric growth parameters studied on the different formulated substrates.