Cultures were maintained on potato dextrose agar (PDA) (Difco) at 25°C, and mycelia for DNA extraction were grown in liquid cultures (120 rpm) at 25°C in potato dextrose broth (PDB) (Difco) for 48 h. Hyphae were collected on filter paper in a Buchner funnel, washed with distilled water, frozen, and lyophilized. Genomic DNA was extracted using the method of Raeder and Broda (31). DNA was resuspended in 50 μl of 10 mM Tris–1 mM EDTA (pH 8) and quantified by use of ethidium bromide fluorescence (35).