Variation in growth at different temperatures and production and size of conidia in hybrid strains of Verticillium lecanii (Lecanicillium spp.) (Deuteromycotina: Hyphomycetes)

抄録

In a previous study, we confirmed alterations in several fungal traits in hybrid strains of Verticillium lecanii generated via protoplast fusion. In the present study, we surveyed radial colony growth in different temperature regimes as well as conidia productivity and conidia size of hybrid strains of V. lecanii to elucidate the various primary fungal properties of these strains and to determine the correlation between these properties and virulence to insect pests. Minimum temperature thresholds for all tested strains (except Vertalec^®) were below 5°C. Optimal temperatures for colony growth were 20–25°C. Colony growth at high temperature was good or poor depending on the genotype. Temperature and strain significantly affected colony growth. Conidial production and conidia size were also significantly affected by strain. Conidial production differed by almost 170 times between the highest conidia-producing strain BbF10 and the lowest conidia-producing strain AaF30, although both strains originated from the same parents. Hybrid strains tended to show slightly larger conidia than their parent strains of the same genotype. Although all these traits varied considerably among hybrid strains, no apparent relationship of these traits with virulence to insect pests was found.