Abstract In 2014, 2000 plants showing root rot symptoms were collected from 200 commercial soybean (Glycine max L.) fields in South Dakota, USA. One thousand one hundred thirty fungal isolates obtained from the samples were identified as Fusarium species by morphology and sequencing of the translation elongation factor 1-alpha gene. Fifty-one percent were F. graminearum, 30.0% were F. acuminatum, 8.0% belonged to the F. oxysporum species complex, 3.4% were F. armeniacum, 2.0% were F. proliferatum, 1.6% were F. virguliforme, 1.2% belonged to the F. solani species complex, 0.4% were F. nanum (syn. F. incarnatum-equiseti species complex), 0.1% were F. bulbicola (syn. F. fujikuroi species complex) and 0.1% were F. commune. The pathogenicity of 57 isolates was evaluated on the soybean ‘Asgrow 1835’ under greenhouse conditions. Root rot severity was rated 14 days after inoculation on a 1-to-5 scale and expressed as relative treatment effects (RTE). Nine isolates of F. oxysporum, and one each of F. armeniacum and F. commune, caused significantly greater RTE than in the non-inoculated control. Twenty-one accessions were screened for resistance in the greenhouse using one isolate each of F. graminearum, F. proliferatum and F. sporotrichioides. Accession PI361090 was less susceptible to F. graminearum and F. proliferatum than the susceptible controls, ‘Williams 82’ and ‘Asgrow 1835’. All accessions were more susceptible to F. sporotrichioides. These findings suggest that 11 Fusarium species or species complexes are pathogenic to soybean in South Dakota, and PI361090 may be a useful source of resistance to F. graminearum and F. proliferatum.

中文翻译：

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美国南达科他州引起大豆 (Glycine max L.) 根腐病的镰刀菌物种特征

摘要 2014 年，从美国南达科他州的 200 个商业大豆 (Glycine max L.) 田中收集了 2000 株表现出根腐病症状的植物。通过翻译延伸因子 1-α 基因的形态学和测序，从样品中获得的一千一百三十株真菌被鉴定为镰刀菌属物种。51% 为禾谷镰刀菌，30.0% 为尖头镰刀菌，8.0% 为尖孢镰刀菌复合体，3.4% 为 F. armeniacum，2.0% 为 F. proliferatum，1.6% 为 F. virguliforme，1.2%属于 F. solani 物种复合体，0.4% 为 F. nanum（同义词 F. incarnatum-equiseti 物种复合体），0.1% 为 F.bulbicola（同义词 F. fujikuroi 物种复合体）和 0.1% 为 F.commune。在温室条件下对大豆 'Asgrow 1835' 评估了 57 个分离株的致病性。根腐病严重程度在接种后 14 天以 1 到 5 的等级评定，并表示为相对处理效果 (RTE)。F. oxysporum 的 9 个分离株以及 F. armeniacum 和 F. community 各一个，引起的 RTE 显着高于未接种的对照。使用禾谷镰刀菌、增殖镰刀菌和孢子镰刀菌各一种分离物在温室中筛选了 21 个种质的抗性。与易感对照“Williams 82”和“Asgrow 1835”相比，登记PI361090 对禾谷镰刀菌和增殖梭菌的敏感性较低。所有种质都更容易受到 F. sporotrichioides 的影响。这些发现表明 11 种镰刀菌属物种或物种复合体对南达科他州的大豆具有致病性，而 PI361090 可能是对禾谷镰刀菌和增殖镰刀菌产生抗性的有用来源。