Abstract :
The mycelia growth rate, physical characteristics of first flush, number of flushes and biological efficiency of twenty three exotic strains of eight Pleurotus species grown on composted sawdust of Triplochiton scleroxylon K (Schum) were studied. The mycelia growth rate per week showed significant differences (P < 0.05) among the strains for the first and third week of growth. P. djamour strain PDA-1, P. eryngii strain PEA-1, P. ostreatus strain POA-7, showed no mycelia growth and flushes within the study period. P. solimoneo-stramineus strain PSSC-1 and P. citrinopileatus strain PCC-1 showed very poor and patchy growth and the mycelium never fully colonised the substrate. This indicates that the different strains of the mushrooms utilize the given substrate at different rates. The heaviest cap weight was recorded for P. ostreatus strain POA-1 which ranged from 9.5-49.5 g for the first flush of mushrooms with its corresponding diameter ranging from 7.7-13.45 cm. With the exception of P. sajor-caju strain PSCA-1 and P. citrinopileatus strain PCC-1 which produced only one flush, all strains produced at least two flushes. P. ostreatus strain POA-9; the highest yielding strain produced four flushes. With all the strains flush 1 gave the highest yield of 98.5 g, and flush 4 the lowest yield of 2.36 g. In general, P. ostreatus strains recorded the highest yields and corresponding biological efficiencies (BE) whilst P. solimoneo-stramineus strain PSSC-1 produced the lowest. Significant differences (P < 0.05) in the yield of the different species and strains were recorded. Further cultivation of P. ostreatus strain POA-9 will be encouraged among farmers since its BE values are comparable with P. ostreatus strain EM-1 currently on the Ghanaian market.
