香荚兰根腐病菌硝酸盐营养突变类型及营养亲和性

利用氯酸盐对从西双版纳、河口、海南香荚兰种植园根腐病标样中分离得到36个尖孢镰刀菌进行诱变。诱导获得459个nit突变体，并用不同氮源培养基对突变体进行鉴定，划分出nit1、nit3、nitM、nitX等4种突变类型，其中nit1出现的频率最高，nitM亲和性最强。经配对实验将36个菌株归为15个VCG组群，表明尖孢镰刀菌香荚兰专化型的群体遗传多样性，且VCG组群与菌株的地理分布有一定的相关性。

Nitrate Nonutilizing Mutants of Fusarium oxysporum f. sp. vanillae and Their Vegetative Compatibility

Thirty-six strains of Fusarium oxysporum f.sp. vanillae isolated from Xishuangbanna, Hekou and Hainan were determined by vegetative compatibility groups. Four hundred and fifty-nine nitrate nonutilizing mutants were recovered from 36 strains of Fusarium oxysporum, and these mutants were divided into four phenotypic classes by their ability to utilize various nitrogen sources,i.e.nit1,nit3, nitM and nitX. The frequency of nit1 phenotype was high. The compatibilities between different nit phenotypes varied, in which nitM with every nit phenotype were high. The 36 strains, were assigned to 15 vegetative compatibility groups based on pairing of complementary nit mutants on the media MM. The result showed that the colony of Fusarium oxysporum f.sp. vanillae Gordon was rich in genetic diversity,and showed definite relation to the distribution of vanilla.