Storage and survival studies on different strains of Volvariella volvacea (Bull. Ex. Fr.) Singer

The study aimed to determine the effect of storage of isolates on the maintenance of growth characteristics and survival ability of ten strains of Volvariella volvacea. Studies were conducted by varying storage media, temperature levels and using different storage techniques. The effect of storage of spawn at varying temperature levels was also evaluated. The characteristics of ten different strains in culture media, spawn and in fruiting bags varied from one another. Good colony growth and spawn run guaranteed desirable fruiting characters of V. volvacea as shown by strains 659 and 566. Recovery growth of the straw mushroom was affected by the interaction of strain and medium during storage. Although choice of medium depended on the strain stored, recovery growth of most of the strains did not vary significantly with storage medium. Strains 566, 567, 600, and 659 consistently gave larger colony, diameter of recovery growth. Most of the strains survived 6-month storage in PDA [potato dextrose agar] at 20 deg C in test tubes with cotton plugs. Strains 600 and 659 showed good survival ability over a wide range of storage temperatures up to 6 months. Response to storage temperature also depended on the strains. Five-month storage in screw-crapped test tubes gave better recovery at all temperature levels except 20 deg C for both 566 and 659 storage in test tubes with cotton plugs gave satisfactory recovery growth at lower temperature (15-20 deg C). Storage technique and storage temperature both determined recovery growth of strains 566 and 659. Three-month old spawn stored at 30 deg C gave the highest yield of Volvariella. Yield of stored spawn was generally higher than yield from unstored spawn but the difference was not significant. Yield potential was still present even in 3-month old spawn stored at varying temperature levels.