Life-history strategy in Typhula incarnata and T. ishikariensis biotypes A, B, and C as determined by sclerotium production

Abstract

The life-history strategies of Typhula incarnata and T. ishikariensis, the snow mold fungi, were studied in culture experiments. Radial mycelial growth at 0 °C, a temperature at which they thrive under natural conditions, was about half that of growth at the near-optimal temperature, 10 °C. However, when the colonies were covered with unsterile soil, mycelial growth at 0 °C was much greater than at 10 °C. Sclerotium production by T. incarnata was rapid in the latter half of the culture period, and sclerotium maturation was promoted by selected fungi. Typhula incarnata produced sclerotia frequently along the junction with colonies of selected fungi. Typhula ishikariensis biotype A produced the highest percent sclerotial biomass. Sclerotium maturation, i.e., pigmentation, was not stimulated by the selected fungi, but sclerotium production was moderately frequent in dual cultures with them. Typhula ishikariensis biotypes B and C produced the lowest percent sclerotial biomass. Their sclerotium maturation was rapid but not stimulated by the selected fungi. These findings suggest that although these snow mold fungi are, as a whole, stress tolerant, T. incarnata is relatively ruderal, T. ishikariensis biotype A is typically stress tolerant, and T. ishikariensis biotypes B and C are adapted to habitats with high stress and high disturbance.