Effects of culture conditions on the growth and morphology of 20 strains of Drechslera avenae (Eidam) Scharif

Growth and sporulation of 20 single-spore isolates of Drechslera avenae grown on different agar media were investigated at 24°C and 11°C. Four different agar media were used - water agar (WA, 20 g agar x l-1), maltose-peptone agar (MPA, 20 g maltose from Difco, 2.5 g peptone, 20 g agar x l-1), potatodextrose agar (PDA, from Difco, 39 g x l-1), and rye agar (RA). The isolates were evaluated in respect of growth, colony colour, and formation of morphological structures. The study showed differences between isolates in respect of colony growth, depending on culture conditions. Comparing macroscopic features of all D. avenae isolates tested, three groups of strains formed equal colonies and four individual strains were separated. Generally, most strains, except strains number: 2, 4, 7, 9, 10, 13 and 17, grew faster on all agar media at 24°C than at 11°C. In case of D. avenae isolates, hyphal growth was the fastest on MPA medium and the slowest on WA. All strains investigated produced typical conidiophores and conidia both at 24°C and 11°C, but at 24°C earlier sporulation was observed. MPA and RA were the best media for the sporulation of D. avenae strains. Sporulation of this species was the latest on WA