Breeding And Analyzing Of The Highly Compatible Strains Of Paecilomyces Cicadae(Miquel) Samson

Now many countries were paying attention to biocontrol using fungi agents, but the testing results in fields were out of people's expectation. This showed that it is much important to improve the virulence of entomopathogenic fungi to make effective production for biocontrol. This paper was a preliminary work for continuable producing more virulent biocontrol strains through breeding more vegetablely compatible parent strains and studying the contitions of diploidization and analyzing the traits of stains mentioned above so as to achieve the relatively stable effects of biocontrol.Thirty-two single condium isolates were obtained from seven strains of Paecilomyces cicadae (Miquel)Samson that were collected from YunNan and GuiZhou provinces. On KPS containing 2%(w/v) KClO₃, several sectors were appeared from different directions of one clone after incubating at 25℃ around for five days. These sectors could be divided into three types. When 110 sectors were selected and inoculated on minimal medium, we obtained sixty nitrate nonutilizing (nit) mutants from them through comparing their morphology of clones. It showed that there was no special corresponding relation between nit mutants and sector types. When vegetative compatibility tests were carried out by pairing the sixty nit mutants on minimal medium at 25℃ for twenty-one days, only seven nit mutants collected from MoJiang of YunNan province were vegetatively compatible while others showed negative reaction. The hypha in mating line stained by Hoechest 33258 showed that hypha with two or more nucleus and phenomenon of H" anastomosis were abounding. But we didn't find any conidia with two or more nuclei. After conidia suspending liquids of the heterocaryons were radiated quantitatively and inoculated on medium supplied with camphor, three assumed diploid strains were selected out through testing its hereditary characters and stability etc. when the nuclei diameters were measured, the results showed that the nuclei diameters of assumed diploid strains were distinctly bigger than those of other strains.When we analyzed all strains'electrophoretogram of soluble protein and content of extra-polysaccharide and virulence to pests in greenhouse (aphid) and activity of chitinase...