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osu1259765346.pdf (1.18 MB)
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Epidemiology and Variability of Disease and Deoxynivalenol in Fusarium Head Blight of Wheat in Ohio
Author Info
Odenbach, Kylea J.
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1259765346
Abstract Details
Year and Degree
2009, Master of Science, Ohio State University, Plant Pathology.
Abstract
Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schwein.) Petch), is the causal agent of Fusarium head blight (FHB), a fungal disease of wheat and other small grain. This fungus produces a trichothecene mycotoxin, deoxynivalenol (DON), which accumulates in infected grain. The United States Food and Drug Administration has issued a 2 ppm advisory limit for DON in unprocessed grain intended for human consumption. In this study, the effect of host resistance, growth stage at infection, and inoculum density, as well as the interactions of these factors, were evaluated on disease measures and DON content of grain under different environmental conditions. A second study, overlaid on the first, evaluated the same effects on DON and F. graminearum colonization of grain from wheat spikes asymptomatic for FHB. The experimental design was a randomized complete block with a split-split-split plot treatment structure, with planting date (PD) as the whole plot, wheat cultivar (CV) as the sub-plot, infection time (IT) as the sub-sub plot, and inoculum density (ID) as the sub-sub-sub plot. Main effects of CV, IT, and ID were significant in both years for DON and visual measures of disease. The greatest DON levels for the two years were seen when temperatures were cool (<20°C) at anthesis. In general DON and disease were greatest for the earliest (anthesis) infection time and increased with increasing levels of inoculum. Infections that occur at post-anthesis growth stages are sub-optimal for FHB development, yet interactions with high inoculum densities, and favorable weather conditions resulted in compensations in disease and toxin concentration. DON exceeded the acceptable limit of 2 ppm for late infections in symptomatic and asymptomatic infections and in susceptible and more resistant cultivars. These results have implications for FHB management. Since DON can be unacceptably high in grain from late season and asymptomatic infections, care should be taken to plant cultivars with high levels of resistance to toxin accumulation. In addition, it may be worthwhile to apply fungicides at post-anthesis growth stages when environmental conditions are conducive for F. graminearum infections. More research needs to be done to identify specific conditions that warrant additional fungicide applications. DON in grain is highly variable at any given level of visual symptoms on external wheat tissues. As a result, accurate in-field toxin quantification is difficult. Variability of disease and DON was evaluated for plots of six winter wheat cultivars with different levels of resistance to FHB. In the final study, DON and disease index were quantified for 30 clusters of 20 spikes in each plot. Seven nonlinear mixed models were generated for DON prediction based on the level of observed disease for clusters and plots means. The best performing models contained a non-constant error term that incorporated the variance of DON into the residual. Future work will focus on the development of a dynamic sampling-protocol for DON for which determination of sample size will incorporate the level of in-field disease and variability in DON, in an effort to increase the accuracy of in-field DON quantification.
Committee
Pierce A. Paul, PhD (Advisor)
Larry V. Madden, PhD (Committee Member)
Clay H. Sneller, PhD (Committee Member)
Pages
146 p.
Subject Headings
Epidemiology
;
Plant Pathology
Keywords
Fusarium head blight
;
Fusarium graminearum
;
deoxynivalenol
;
epidemiology
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Citations
Odenbach, K. J. (2009).
Epidemiology and Variability of Disease and Deoxynivalenol in Fusarium Head Blight of Wheat in Ohio
[Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259765346
APA Style (7th edition)
Odenbach, Kylea.
Epidemiology and Variability of Disease and Deoxynivalenol in Fusarium Head Blight of Wheat in Ohio.
2009. Ohio State University, Master's thesis.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1259765346.
MLA Style (8th edition)
Odenbach, Kylea. "Epidemiology and Variability of Disease and Deoxynivalenol in Fusarium Head Blight of Wheat in Ohio." Master's thesis, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259765346
Chicago Manual of Style (17th edition)
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Document number:
osu1259765346
Download Count:
616
Copyright Info
© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.