Productivity of Agaricus brunnescens stock cultures following 5-, 7-, and 10-year storage periods in liquid nitrogen

Eight cultivars of the commercial mushroom, A. brunnescens, were preserved in liquid nitrogen for 10 years with no apparent changes in morphological or physiological characteristics. With one exception, cropping trials after 5-, 7-, and 10-years storage showed no significant differences in the productive capacity of frozen cultures as compared to the same cultivars maintained by conventional mycelial transfer. Cryogenic preservation of mushroom stock cultures was shown to be a realistic, practical method of long-term conservation. The major advantages of nitrogen storage are the preservation of the original genetic lines, protection of cultures from loss through contamination or mutation, and the reduction of time, materials, labor and space necessary for conventional maintenance.