Interaction between Triticum aestivum Plants and Four Fusarium Head Blight Species on the Level of Pathogenicity: Detected in an in vitro Petri-dish Assay.

The interaction between bread wheat (Triticum aestivum L.) plants and four filamentous species of the Fusarium genus (the causal agent of Fusarium head blight, FHB) was analyzed in an in vitro Petri-dish assay. Pathogenicity criteria as well as germination rate reduction, standardized area under disease progress curve (AUDPC_standard), and coleoptile length reduction were investigated in seeds and six-day-old seedlings showing a moderately level of quantitative resistance, after inoculations with 16 FHB isolates. AUDPC_standard did differentiate FHB isolates and the other two pathogenicity criteria did not. It was not possible to cluster the isolates based on their species origins because of similarity in pathogenic level among the 16 fungal isolates. Cultivar-specific pathogenicity has been detected. The values of disease incidence and disease severity involved in previous artificial head and floret inoculations showed significant correlation with AUDPC_standard: r=0.653** and r=0.559*, respectively. AUDPC_standard could be of potential use in evaluating the pathogenicity of FHB in adult wheat plants. [ABSTRACT FROM AUTHOR]