Abstract: The aim is to clarify the root rot pathogen of Isatis indigotica Fort.in the main producing area and the disease resistance of different germplasms.The inoculation effects of three methods were first compared，including root injection，fungal block inoculation and root irrigation methods.And the concentration of root injection method was optimized. Subsequently，I.indigotica pathogens were isolated by tissue separation method.The pathogenicity of the pathogens was determined by the method of injection. Combined with the morphology and gene sequences of ITS，TEF and Tub，the species were identified.Finally，by using the optimized pathogen inoculation method and the most pathogenic strain isolated，the disease resistance of 58 I.indigotica germplasms collected from different producing areas was measured and evaluated.The results showed that the best identification method for resistance to I.indigotica root rot was root injection inoculation with the conidial concentration of 1×10⁷ cfu/mL.Among 36 samples from Heilongjiang，Shanxi，Henan，Xinjiang and Gansu，a total of 68 fungi were isolated.One strain of XJG39 was selected as the strongest pathogenicity through pathogenicity test.Through morphological observation and molecular biological identification，XJG39 was determined to be Fusarium solani.Through disease⁃resistance analysis，5 resistant germplasms（8.62%） and 7 lowly resistant germplasms（12.07%）were selected.There were 39 susceptible germplasms and 7 highly susceptible germplasms（accounting for 79.31%）.The resistance level of root rot was low for most cultivated germplasms in the main producing area of I.indigotica，which was one of the important reasons for the frequent occurrence of root rot.The five selected germplasms can be used as valuable resources for the subsequent research on resistance breeding and resistance genetics of I.indigotica.

Key words: Isatis indigotica Fort., Root rot, Pathogen identification, Inoculation method, Resistant germplasm screening

摘要： 为明确菘蓝种植区菘蓝根腐病病原菌及不同菘蓝种质的抗病性差异，首先比较了注射法、菌块法和灌根法3种病原菌回接方法的接种效果，并优化了注射法的接种浓度；随后采用组织分离法分离菘蓝病样的病原菌，并采用注射法回接确定病原菌的致病性，结合病原菌形态和ITS、TEF、Tub基因序列确定病原菌种类；最后利用优化的病原菌接种鉴定方法和分离得到的致病性最强的菌株对58份不同种植区菘蓝种质的抗病性进行测定和评价。结果表明，菘蓝根腐病抗性鉴定的最佳接种方法为注射法，注射菌液的适宜浓度为1×10⁷ 个/mL。从来自黑龙江、山西、河南、新疆和甘肃5个种植区的36个菘蓝根腐病病样中共分离出68株真菌，通过致病性测定发现XJG39致病性最强，通过形态学观察与分子生物学鉴定确定XJG39为茄腐镰刀菌（Fusarium solani）。通过抗性鉴定，筛选出5份抗病种质（占比8.62%）、7份低抗种质（占比12.07%）、39份感病种质和7份高感种质（共占比79.31%）。可见，菘蓝种植区大部分栽培种质的根腐病抗病水平较低，筛选出的5份抗病种质可作为菘蓝抗病育种和抗性遗传研究的宝贵资源。

关键词: 菘蓝, 根腐病, 病原鉴定, 接种方法, 抗病种质筛选