Mycosystema. 1995, 14(Z1): 137-151.
Two wild-type multi-spore isolates of Beauveria bassiana and some single spore isolates from them were subcultured on 7 artificial media under different conditions of temperature, humidity and light. The results showed that substantial saltation of 3 different types occured mainly due to different growth rates and morphologies of original colony and sectorial variation area. The variation of morphology, color, growth rate and sporulation of these segregants derived from the sectors under different conditions was tested and compared. The initial wild- type isolates degenerated within 4-14 generations. Medium, temperature, humidity, and light induced the variation obviously. Cultures on SDAY at 15℃, comparatively low humidity, and under full light resulted in low frequency variation. Noticebly, segregants derived from the single-spore isolates produced brownish yellow or reddish brown pigment secretion, suggesting the unreliablity of specy division by culture characteristics such as colony color and morphology. In addition, growth rate increase was followed by sporulation decline. They were negatively correlated. Some possible approach to the strain variation were proposed involving genetic mechanisms inner and outer nuclei.
