Skip to main content
ARS Home » Southeast Area » Raleigh, North Carolina » Plant Science Research » Research » Publications at this Location » Publication #229468
Title: Post-flowering moisture increased Fusarium head blight and deoxynivalenol levels in North Carolina field experiment with winter wheat

Author
item Cowger, Christina
item Patton Ozkurt, Jennifer
item Brown-Guedira, Gina
item PERUGINI, LEANDRO - PIONEER HI-BRED

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2008
Publication Date: 4/5/2009
Citation: Cowger, C., Patton Ozkurt, J.L., Brown Guedira, G.L., Perugini, L. 2009. Post-flowering moisture increased Fusarium head blight and deoxynivalenol levels in North Carolina field experiment with winter wheat. Phytopathology. 99:320-327.

Interpretive Summary: Current models to forecast Fusarium head blight (FHB) and deoxynivalenol (DON) levels in wheat are based on weather near anthesis, and breeding for resistance to Fusarium often relies on irrigation before and shortly after anthesis to encourage disease development. The effects of post-anthesis environmental conditions on FHB are poorly understood. We performed a field experiment at Kinston, North Carolina, to explore the effects of increasing durations of post-anthesis moisture on disease incidence, disease severity, Fusarium-damaged kernels (FDK), percent infected kernels, and deoxynivalenol (DON). Two trials were conducted in successive years, and the experiment had a split-plot design. Main plots consisted of post-anthesis mist durations of 0, 10, 20, or 30 days. Sub-plots were of eight cultivars in the first year and seven in the second year, two being susceptible to FHB and the remainder each with varying putative degrees of Type I and Type II resistance. Plots were inoculated by spraying F. graminearum macroconidia at mid-anthesis. Averaging across years and cultivars, 10 or 20 days of post-anthesis mist had the same effect (P = 0.198) and were associated with an approximately four-fold increase in mean disease incidence (DI) and eight-fold increase in disease severity (DS) as compared to 0 days mist (P = 0.0002). In both years, mean FDK percentages at 0 and 10 days’ post-anthesis mist were the same, and were significantly lower than FDK percentages under 20 or 30 days of post-anthesis mist. Mist duration had a significant effect on percent of kernels infected with Fusarium as detected by a selective medium assay of 2007 samples. Averaging across all cultivars, in both years DON levels increased significantly with 10 days as compared to 0 days mist, and increased again with 20 days of mist (P = 0.04). For all disease and toxin assays, cultivar rankings were significantly non-correlated among mist durations in at least one year, suggesting that FHB screening programs might rank genotypes differently under extended post-anthesis moisture than without it. Our findings also imply that accurate forecasts of DON in small grains must take account of post-anthesis weather conditions.

Technical Abstract: Current models to forecast Fusarium head blight (FHB) and deoxynivalenol (DON) levels in wheat are based on weather near anthesis, and breeding for resistance to Fusarium often relies on irrigation before and shortly after anthesis to encourage disease development. The effects of post-anthesis environmental conditions on FHB are poorly understood. We performed a field experiment at Kinston, North Carolina, to explore the effects of increasing durations of post-anthesis moisture on disease incidence, disease severity, Fusarium-damaged kernels (FDK), percent infected kernels, and deoxynivalenol (DON). Two trials were conducted in successive years, and the experiment had a split-plot design. Main plots consisted of post-anthesis mist durations of 0, 10, 20, or 30 days. Sub-plots were of eight cultivars in the first year and seven in the second year, two being susceptible to FHB and the remainder each with varying putative degrees of Type I and Type II resistance. Plots were inoculated by spraying F. graminearum macroconidia at mid-anthesis. Averaging across years and cultivars, 10 or 20 days of post-anthesis mist had the same effect (P = 0.198) and were associated with an approximately four-fold increase in mean disease incidence (DI) and eight-fold increase in disease severity (DS) as compared to 0 days mist (P = 0.0002). In both years, mean FDK percentages at 0 and 10 days’ post-anthesis mist were the same, and were significantly lower than FDK percentages under 20 or 30 days of post-anthesis mist. Mist duration had a significant effect on percent of kernels infected with Fusarium as detected by a selective medium assay of 2007 samples. Averaging across all cultivars, in both years DON levels increased significantly with 10 days as compared to 0 days mist, and increased again with 20 days of mist (P = 0.04). For all disease and toxin assays, cultivar rankings were significantly non-correlated among mist durations in at least one year, suggesting that FHB screening programs might rank genotypes differently under extended post-anthesis moisture than without it. Our findings also imply that accurate forecasts of DON in small grains must take account of post-anthesis weather conditions.