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为了明确天竺葵腐霉枯萎病的病原菌种类,从内蒙古通辽采集天竺葵腐霉枯萎病样品,对病原物进行了分离、纯化和致病性测定,并对病原物进行形态学和rDNA-ITS序列分析鉴定。结果表明,从10个植物样品中分离得到16个腐霉菌株,分别属于终极腐霉Pythium ultimum var.ultimum、瓜果腐霉P.aphanidermatum和两个与P.ultimum var.ultimum相似的待定种。其中,P.ultimum var.ultimum的分离频率为75%、P.aphanidermatum的分离频率为12.5%,两个腐霉待定种的分离频率均为6.25%;P.ultimum var.ultimum是优势类群。致病性测定结果表明,4种腐霉菌都能引起天竺葵腐霉枯萎病,与自然发病症状相同,其中P.ultimum var.ultimum和P.aphanidermatum的致病性较强,发病率分别为71.4%和85.7%。
In order to clarify the pathogen species of Pythium blight in Geranium natans, the samples of Pythium fortunei wilt disease were collected from Tongliao, Inner Mongolia, and the pathogens were isolated, purified and pathogenicity tested. Morphological and rDNA-ITS sequence analysis . The results showed that 16 Pythium strains were isolated from 10 plant samples, belonging to Pythium ultimum var. Multimum, P. aphanidermatum and two similar species to P.ultimum var. Multimum respectively. The separation frequency of P. polymum var.ultimum was 75%, that of P. aphanidermatum was 12.5%, and that of P. pyrifolium was 6.25%. P. multimum var. Multimum was the dominant group. The results of pathogenicity test showed that all four Pythium strains could cause Pythium blight, which was the same as the natural pathogen. The pathogenicity of P.ultimum var.ultimum and P. aphanidermatum were high, the incidence rates were 71.4% And 85.7%.