Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA.
Phytopathology. 2013 Aug;103(8):822-32. doi: 10.1094/PHYTO-08-12-0207-R.
Fusarium spp. are commonly isolated from soybean roots but the pathogenic activity of most species is poorly documented. Aggressiveness and yield impact of nine species of Fusarium were determined on soybean in greenhouse (50 isolates) and field microplot (19 isolates) experiments. Root rot severity and shoot and root dry weights were compared at growth stages V3 or R1. Root systems were scanned and digital image analysis was conducted; yield was measured in microplots. Disease severity and root morphology impacts varied among and within species. Fusarium graminearum was highly aggressive (root rot severity >90%), followed by F. proliferatum and F. virguliforme. Significant variation in damping-off (20 to 75%) and root rot severity (<20 to >60%) was observed among F. oxysporum isolates. In artificially-infested microplots, root rot severity was low (<25%) and mean yield was not significantly reduced. However, there were significant linear relationships between yield and root symptoms for some isolates. Root morphological characteristics were more consistent indicators of yield loss than root rot severity. This study provides the first characterization of aggressiveness and yield impact of Fusarium root rot species on soybean at different plant stages and introduces root image analysis to assess the impact of root pathogens on soybean.
镰刀菌属真菌通常从大豆根部分离出来，但大多数物种的致病性活动记录甚少。在温室（50 个分离株）和田间小区（19 个分离株）实验中，确定了 9 种镰刀菌对大豆的侵袭性和产量影响。在 V3 或 R1 生长阶段比较根腐病严重程度和地上部和根干重。扫描根系并进行数字图像分析；在小区中测量产量。疾病严重程度和根系形态的影响在种间和种内均有所不同。禾谷镰刀菌具有高度侵袭性（根腐病严重程度>90%），其次是层出镰刀菌和弯孢镰刀菌。在尖孢镰刀菌分离株中观察到猝倒病（20%至 75%）和根腐病严重程度（<20%至>60%）的显著差异。在人工接种的小区中，根腐病严重程度较低（<25%），平均产量没有明显降低。然而，对于某些分离株，产量与根症状之间存在显著的线性关系。与根腐病严重程度相比，根系形态特征是产量损失更一致的指示因子。本研究首次对不同植物阶段大豆镰刀菌根腐病的侵袭性和产量影响进行了描述，并引入了根系图像分析来评估根病原菌对大豆的影响。
