Selection of the best commercial strain of paddy straw mushroom (Volvariella volvacea (Bull.ex.Fr.) Sing.).

摘要

Four strains of paddy straw mushroom (V. volvacea), i.e. PS1, PS2, PS3 and PS4, were subcultured in Petri plates (90 mm) on PDA medium and incubated at 30+or-2 degrees C. The colony diameter was measured periodically to select the best strain under in vitro condition. Formation of chlamydospores was observed. Well-dried and good-quality paddy straw was chopped into small pieces (4-6 cm long), soaked in water for ~24 h (excess water was drained out) and shade-dried. Horse gram powder was mixed with paddy straw at the rate of 10% to wet weight, filled in polypropylene bags and sterilized in an autoclave at 1.46 Kg/cm2 for 1 h. After cooling, the bags were inoculated with mycelial culture of PS1, PS2, PS3 and PS4 strains separately and incubated for ~16-18 days at 30-35 degrees C for complete spawn run and chlamydospore formation. These spawn were used for mushroom bed preparation. The straw was made into small twists of 2.5 m long and 5-8 cm diameter, weighing ~0.5-0.75 kg. Four twisted bundles formed one bed (30x30 cm), weighing 2.5 kg. The twisted bundles were immersed in clean cold water for ~24 h. They were taken out and kept for few hours to drain the excess water and shade-dried to have 65-75% moisture. Initially, the twists were wound clockwise in a circular fashion as close as possible. Then, the coarsely powdered horse gram was sprinkled over the small bits of spawn, which were placed previously all along the periphery. A second layer was built over this in the same manner and spawned. Likewise, third and fourth layers were formed. The completed bed was pressed tightly and kept in a polyhouse at 32-35 degrees and 80-85% relative humidity. The beds were regularly sprayed with clean water. The yield parameters were recorded periodically. PS1 and PS4 strains showed vigorously growing mycelia of 'NN' type and produced the maximum biomass in spawn bags. PS1 and PS4 showed earlier spawn run compared to PS2 and PS3. Among the strains, PS1 recorded the highest yield of 1173.00 g/bed, followed by PS4 (1146.00 g/bed). Thus, PS1 was selected as the best strain for commercial cultivation..