Effect of Plant Growth Promoting Rhizobacteria (PGPR) onYield and Quality of Button Mushroom in Different Industrial and Agricultural Wastes as Growth Beds

In order to evaluate the effects of plant growth promoting rhizobacteria (PGPR) on some quality and quantity traits of button mushroom (Aaricus bisporus) in different industrial and agricultural wastes as growth beds, a factorial experiment was conducted, using a completely randomized design with three replications. Five different beds were used containing wheat straw as the main substance and powdered supplements of fish meal, slaughter-house wastes, olive wastes, and cattle and chicken manures. The beds were inoculated with mixture of Bacillus and pseudomonas, except the uninoculated control. The results indicated that the effects of bed types, PGPR inoculation, and their interactive effects were significant on fresh and dry weight, nutrient elements concentrations, and protein contents of mushroom, but had no significant effects on the number and ash contents of mushrooms. The highest fresh weight (751.5 gr plot-1) of the mushrooms were measured in the bed with cattle manure inoculated with PGPR, whereas the lowest (592.6 gr plot-1) were obtained from the bed containing slaughter-house wastes without PGPR inoculation. Also, the highest (7.1%) and the lowest (4.4%) dry matter of the mushrooms were obtained from the bed containing chicken manure with PGPR inoculation and the bed containing fish meal wastes without PGPR inoculation, respectively. The highest protein contents (29.25%) and concentrations of N, P, Mg, Zn, and Cu were obtained from the bed containing fish meal wastes with PGPR inoculation, while the bed containing cattle manure without any inoculation and the bed containing olive wastes with PGPR inoculation had the lowest protein contents (17.27%) and the highest Fe concentration, respectively. In general, in this experiment the effect of PGPR on fresh and dry weight as well as on protein contents of button mushroom was significant and positive.