The efficacy of sorghum and millet grains in spawn production and carpophore formation of Pleurotus ostreatus

Sorghum and millet grains were assessed as single treatments and combined in various proportions to determine their suitability for production of spawns and carpophores of Pleurotus ostreatus (Jacq. Ex. Fr) Kummer. The mycelia growth rates on the grains, one of the parameters assessed, were measured from the third to the ninth day of incubation. In addition, for each replicate of the various treatments, the days from inoculation of the bottles till total colonization was recorded. The combination of sorghum and millet grains in a 3:1 (w/w) ratio showed fastest mycelial growth of 16 days followed by sorghum only recording a value of 18 days. These were however not significantly different (P>0.5). The best grain treatments were used as inocula on composted sawdust of Triplochiton scleroxylon to compare their yield characteristics. Parameters assessed during fruiting included the number and weight of carpophores obtained, flush number and biological efficiency (BE). No significant difference in BE was observed. Based on the results obtained, for large-scale P. ostreatus spawn production, a combination of sorghum and millet grains in a 3:1 ratio would be most appropriate for use as substrate.