黑龙江省哈尔滨市苜蓿镰孢根腐病病原菌分离鉴定

Isolation and identification of pathogens of Fusarium root rot on alfalfa in Harbin City, Heilongjiang Province

摘要:

【目的】明确黑龙江省哈尔滨市苜蓿根腐病病原菌种类。【方法】采集 38 株黑龙江省哈尔滨市农业科学院示范区的苜蓿根腐病病株，经组织分离法分离致病菌，通过科赫氏法则验证其致病性并结合形态学和 rDNA-ITS 序列分析鉴定病原菌。【结果】从患有苜蓿根腐病的病根分离并选取具有代表性的 5 株真菌 KY1、J1、S1、SA1、C1，分别被鉴定为腐皮镰孢(Fusarium solani)、尖镰孢(F. oxyspo- rum)、水稻恶苗病菌(F. fujikuroi)、三线镰孢(F. tricinctum)和层出镰孢(Fusariumproliferatum)。致病性测定表明 5 株真菌均为苜蓿根腐病致病菌。【结论】腐皮镰孢不仅分离率最高，为 57. 45%，且致病性也较强，病情指数为 61. 00，是优势病原菌。

Abstract:

【Objective】 To clarify the pathogenic species of Fusarium root rot of alfalfa in Harbin City，Heilongji‐ ang Province.【Method】 Thirty ‐ eight alfalfa root rot disease strains were collected from the demonstration area of Harbin Academy of Agricultural Sciences in Heilongjiang Province，and the pathogenic fungi were isolated by tissue separation method，verified by Koch's rule and identified by morphology and rDNA‐ITS sequence analysis.【Result】 The five representative fungal strains，KY1，J1，S1，SA1 and C1，were isolated and selected from alfalfa roots and identified as F. solani，F. oxysporum，F. fujikuroi，F. tricinctum and F. proliferatum，respectively. The pathogenicity test showed that all the five fungi were pathogenicfor alfalfa root rot.【Conclusion】 F. solani not only had the highest isolation rate (57. 45%)，but also had strong pathogenicity，with a disease index of 61. 00，which was the dominant pathogen. The alfalfa root rot caused by F. fujikuroi was reported for the first time in China.