POSTERS: Postharvest pathology and mycotoxins
Amylose-free (“waxy”) wheat colonization by Fusarium spp. and response to Fusarium head blight
Deanna Funnell-Harris - 251 Filley Hall, Food Indus Comp.. Stephen Wegulo- Univ of Nebraska, Zachary Duray- USDA-ARS, Patrick O'Neill- USDA-ARS, Robert Graybosch- USDA-ARS
Hexaploid waxy wheat (Triticum aestivum L.) has null mutations in Wx genes, which results in grain lacking amylose with increased digestibility, usability for specialty foods and improved self-life. The waxy cultivar Mattern is susceptible to Fusarium head blight (FHB) caused by Fusarium graminearum species complex that produces the mycotoxin deoxynivalenol (DON). In Experiment 1, conducted during low natural FHB, grain from waxy breeding lines, Mattern, and wild-type breeding lines and cultivars, were assessed for Fusarium infection and DON concentration. Nine Fusarium species and species complexes were detected from internally-infected (disinfested) grain; F. graminearum-infections were not different between waxy and wild-type. Surface- and internally-infected grain (non-disinfested) had more Fusarium isolates in waxy versus wild-type, but F. graminearum-like infections were similar; however, DON levels were higher (P=0.01) in waxy. In Experiment 2, disease severity, Fusarium-damaged kernels (FDK), and DON were assessed for waxy breeding lines, Mattern, and wild-type cultivars during a severe epidemic. Disease severities and FDK were not significantly different from wild-type but DON was higher (P<0.01) in waxy than wild-type lines. Across both experiments, two waxy breeding lines, Plant Introductions 677876 and 677877, responded similarly to FHB as moderately-resistant wild-type cultivar Overland, showing promise for breeding waxy cultivars with FHB resistance.