大丽轮枝菌异核体及其后代的形态与致病力变异*

以硝酸盐利用缺陷型突变（nit突变）和抗杀菌剂突变两种遗传标记，对大丽轮枝菌（Verticilliumdahliae）异核体后代的形态和致病力进行研究，结果表明，菌核型菌株与菌丝型菌株经菌丝融合形成异核体后，菌丝型菌株能恢复形成微菌核，其后代单孢菌落形成微菌核的数量明显低于菌核型亲本，且遗传性状不稳定；随着转代次数的增多，微菌核形成能力的丧失较菌核型亲本菌株快。异核体后代对棉苗的致病力变化较大，一般均低于致病力强的亲本菌株，或介于两个亲本致病力之间，或与亲本致病力相近。

MORPHOLOGY AND VIRLIENCE VARIANCE OF HETEROCARYON OF VERTICILLIUM DAHLIAE AND ITS PROGENIES

Morphology and virulence of V dahliae heterocaryon progenies weretested by using nit mutants and carbendazim resistant mutants. The isolates having andlacking microsclerotia(MS) were paired and the progenies of the heterocaryon wereanalysed. MS Phenotype was recovered in some single spore isolates whose parentwas lacking MS structure,The morphology of these isolates was instable anddissimilar as compared with parent isolates having MS structure. The number of MSwere reduced or lost after repeated transfer in culture. The virulence of these isolateswas lower than that of strong virulence parent isolates and higher than that of weakvirulence parent isolates.