Nutrient Compositions and Optimization of Elephant Grass (Pennisetum purpureum) Stem to Cotton Seed Proportion for the Cultivation of Oyster Mushroom (Pleurotus ostreatus) at Ambo Western, Ethiopia.

At present more emphasis has been given to mushroom cultivation for the nutrition and medicinal uses and Agricultural product recycling technology. The aim of this study was to investigate the usability of Pennisetum purpureum stem as major substrate for cultivation of oyster (Pleurotus ostreatus) mushroom with supplement of different proportion of cotton seed waste. The culture of the oyster mushroom was maintained on potato dextrose agar, and the spawn was prepared on yellow collared sorghum and sterilized substrate was inoculated with 10% of the spawn wet basis on dry basis of the substrate. The experimental design constitutes ten treatments on the stem of elephant grass with ratios of cotton seed wastes (T1-T10) in three replications. At T4 (70:30) the fastest mycelial grow on the stem of elephant grass and Slowest mycelia extension were observed on T7 (60:40). the highest fresh weight were observed on T4 (70:30) stem of elephant were recorded 1254 g / 500g dry substrate, highest number of fruits recorded on T5 (62) while largest cap diameter (11.5cm) was recorded on T2 of the stem of elephant grass the highest stipe length were recorded on T9 (3.67cm) . The highest biological efficiency observed on T4 (250.5%) on stem of elephant grass. the highest protein contents were recorded on T7 (36.17%) on stem of elephant grass with supplementation of cottonseed wastes and the least one were recorded on T9 (80:20) 16.87%, on the others treatments intermediate number of food contents were recorded. Even though on the stem of elephant grass and the proportion supplementation of cotton seed waste was varied for all the treatments except on T1 treatments make 100% Pennisetum purpureum dry stem were made. Over all, the results of the study showed that the Pennisetum purpureum stem supplemented with cotton seed wastes can be gave highest yield and yield related parameters of oyster mushroom. The results of the present study implies to carry out further research on the optimization of Pleurotus ostreatus production using two or more type of substrates tested in this experiment