甜瓜枯萎病菌（Fusarium oxysporum）专化型的初步研究

本研究获得的甜瓜枯萎病病株9株分离物（南通市6株，新疆3株），经PDA培养性状发现，其在菌落颜色、质地和生长速率方面存在差异，大型分生孢子的大小为(19.54～41.11)μm×(4.90～8.16)μm，与西瓜枯萎病菌的大型分生孢子有较大差异。胚根法成株期致病性测定结果发现，本研究的甜瓜枯萎病菌分离物在不同鉴别寄主和鉴别品种上致病性存在专化型和生理小种方面的差异，但分离物中不存在西瓜枯萎病菌。利用核糖体转录间隔区保守序列设计引物，PCR检测也证明本研究甜瓜枯萎病菌不同分离物中不存在西瓜枯萎病菌。

Studies on the differentiation of pathogenicity in Fusarium oxysporum on melon

Nine isolates from Fusarium oxysporum grown on PDA plates had great difference in colony color, texture and growth rate. Their sizes of macroconidia (19.54-41.11)μm ×(4.90-8.16)μm, were significantly different from that of F. oxysporum f.sp. niveum. The results of pathogenicity test in adults indicated that the pathogenicity of F. oxysporum on different living hosts and differential varieties was different in forma specialis and physiologic races, but F. oxysporum f.sp. niveum was not found in the isolates from Fusarium wilt. The results of polymerase chain reaction, with primers designed according to the conservative sequences of the internal transcribed space (ITS) regions of the ribosomal DNA, also proved that no F. oxysporum f.sp. niveum existed in different isolates.