STRAIN VARIATION OF BEAUVERIA BASSIANA IN SUBCULTURING
TANG Xiao-qing , FAN Mei-zhen AND LI Zeng-zhi
Systematic Mycology & Lichenology Laboratory Institute of Microbiology,Academia Sinica Anhui Agricultural University, Hefei,Anhui 230036

ABSTRACT: Two wild-type multi-spore isolates of Beauveria bassiana and some single spore isolates from them were subcultured on 7 artificial media under different condit -ions of temperature, humidity and light. The results showed that substantial sal -tation of 3 different types occured mainly due to different growth rates and mor phologies of original colony and sectorial variation area. The variation of morph -ology,color, growth rate and sporulation of these segregants derived from the se -tors under different conditions was tested and compared. The initial wild-type isol -ates degenerated within 4-14 generations.Medium,temperature,humidity, and light induced the variation obviously.Cultures on SDAY at 15íŠ,comparatively low hu midity, 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 character -istics such as colony color and morphology,In addition, growth rate increase was fo -llowed by sporulation decline.They were negatively correlated.Some possible approach to the strain variation were proposed involving genetic mechanisms inner and outer nuclei.

KEY WORD: Beaveria bassiana;Saltation;Subculture.