Variation within isolates of Typhula incarnata from localities differing in winter climate

Isolates of Typhula incarnata, a snow mold fungus, were collected from four localities with different winter climates. Their ecological traits such as mycelial growth rate, sclerotium size, carpogenic germination of sclerotia, and aggressiveness were compared between populations in order to reveal infraspecific differentiation associated with climatic differences. Population variability was evident only in sclerotium germination: isolates from more snowy localities germinated faster than those from less snowy localities. T. incarnata is regarded as a versatile pathogen with no specialized forms in contrast with T. ishikariensis. The germination rate of sclerotia is considered very critical in the life history of T. incarnata.