A modified filter paper technique for long-term preservation of some fungal cultures

Abstract

A modified filter paper method was found to be very effective for preservation of Marasmiellus inoderma, Ganoderma sp. and Fusarium oxysporum cultures. At −19°C, 75% of M. inoderma isolates were found to be viable after two years of storage, 81% of Ganoderma isolates after five months and 100% of F. oxysporum isolates after four years. All recovered cultures were found to be free from mite infestation. For successful recovery, fungal cultures must be incubated under optimum growth conditions prior to preservation and mycelial mats on filter papers must be properly dried. When compared to conventional freeze-drying methods, this method of preservations is much simpler, less expensive and requires only a cheap vacuum system consisting of a desiccator and a vacuum pressure station, and either a domestic refrigerator or domestic freezer. For small-scale preservation of cultures in the laboratory, this modified method is also less costly than using liquid nitrogen.