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The Role of Environmental, Temporal, and Spatial Scale on the Heterogeneity of Fusarium Head Blight of Wheat

Kriss, Alissa Brynn
http://rave.ohiolink.edu/etdc/view?acc_num=osu1320932280

Abstract Details

2011, Doctor of Philosophy, Ohio State University, Plant Pathology.
Fusarium head blight (FHB) of wheat is a disease of foremost importance in many parts of the world, including Europe and the US. FHB reduces quantity and quality of yield by reducing grain weight and contaminating grain with mycotoxins [especially deoxynivalenol (DON)]. FHB is known to be highly variable at several spatial and temporal scales, which is likely due, in part, to the variability in environmental conditions. Different statistical approaches were used to empirically quantify this heterogeneity in FHB and relate it to environmental conditions. First, window-pane methodology was utilized to determine the length and starting time of temporal windows where environmental variables were associated with: (a) the inter-annual variation in FHB in four US states; and (b) the spatio-temporal variation in FHB, pathogen biomass, and toxin concentration in grain across three European countries. Associations between biological and environmental variables were quantified with Spearman rank correlation coefficients. Atmospheric moisture- or surface-wetness-related variables (e.g., average daily relative humidity) were positively associated with FHB intensity for multiple window lengths and starting times in the US analysis, especially for times shortly before and after anthesis. Results from the European analysis confirmed that FHB intensity was associated with moisture variables, and also showed that biomass of the causal agents and the associated mycotoxins in harvested grain were significantly associated with these same environmental conditions, although mycotoxin concentrations were only associated with post-anthesis conditions. Second, cross-spectral analysis was used to characterize the coherency between inter-annual variation in FHB in Ohio and Indiana and global climate variability. Climate patterns investigated were the Oceanic Niño Index (ONI), the Pacific/North American (PNA) pattern, and the North Atlantic Oscillation (NAO), which are known to have strong influences on the Northern Hemisphere climate and weather. Results showed that the ONI was significantly coherent with FHB in Ohio, especially with a period of about 5.1 years (as well as for some adjacent periods). The estimated phase-shift distribution indicated that there was a generally negative relation between the two series, with high values of FHB estimated to occur less than 1 year after low values of ONI. At periods between 2 and 7 years, the PNA and NAO indices were coherent with FHB in both Ohio and Indiana, although results for phase shift and period depended on the specific location, climate index, and time span used in calculating the climate index. Third, a generalized linear mixed model (GLMM) was fitted to multilevel survey data for the incidence of FHB from the 2002 through 2011 growing seasons in Ohio. Spatial heterogeneity of the complementary log-log link function of expected disease incidence among counties, fields within counties, and sites within fields and counties was quantified through the estimated variance components of the GLMM and their profile-likelihood-based confidence intervals. The GLMM was based on the assumption that the disease status of wheat spikes within sites was binomially distributed conditional on the random effects of county, field, and site. Results confirmed that FHB is sporadic on a spatial scale, and that larger-scale variability can dominate the spatial patterns, with very low variability among sites within fields.
Laurence Madden, PhD (Advisor)
Pierce Paul, PhD (Advisor)
Michael Ellis, PhD (Committee Member)
Clay Sneller, PhD (Committee Member)
253 p.
Plant Pathology
Fusarium head blight; generalized linear mixed models; cross-spectral analysis; window-pane analysis

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Citations

  • Kriss, A. B. (2011). The Role of Environmental, Temporal, and Spatial Scale on the Heterogeneity of Fusarium Head Blight of Wheat [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1320932280

    APA Style (7th edition)

  • Kriss, Alissa. The Role of Environmental, Temporal, and Spatial Scale on the Heterogeneity of Fusarium Head Blight of Wheat. 2011. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1320932280.

    MLA Style (8th edition)

  • Kriss, Alissa. "The Role of Environmental, Temporal, and Spatial Scale on the Heterogeneity of Fusarium Head Blight of Wheat." Doctoral dissertation, Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1320932280

    Chicago Manual of Style (17th edition)

osu1320932280
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© 2011, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.