球孢白僵菌混菌培养的遗传学分析

放线酮抗性及34℃耐受性不同的球孢白僵菌两营养亲和单孢株经混合培养，能够形成异核体。在分生孢子形成的单倍化过程中，异核体中的染色体或其片段发生连续丢失，至少经4代准性循环，遗传性状才会趋于相对稳定。遗传标记及RAPD分析表明，异核体中染色体的丢失并非随机的，重组株的遗传性状表现为倾向选择，即子代主要只表现为某一母株的遗传性状，另一亲本型性状被完全抑制或其遗传物质被丢失。混合比例不同、培养介质不同可影响准性生殖过程及倾向选择频率。混菌培养有利于优良性状的保持。

GENETICAL ANALYSIS ON CROSS INCUBATION OF BEA UVERIA BASSIANA

Heterokaryon of Beauveria bassiana was formed during the cross incubation of two vegetative compatible strains with genetic markers of actidione resistance and 34 degrees C tolerance. The chromosome(s) or its fragment successive losses, recombination and segreation led to haploidization during the conidia formation period. After at least 4 generations of parasexual cycle, the genetic character of heterokayon could get to relative stable. Genetic marker and RAPD analysis indicated that the combinants showed the phenomenon of preferential selection of one parental type by unrandom chromosome lossing and the gene of the other parental strain was suppressed or lost completely. Different culture medium, in vivo or in vitro, and different mixture ratio of original strain spores could affect parasexual process and then the preferential selection. The results also demonstrated the heterosis effect of cross culture.