Author ORCID Identifier

https://orcid.org/0000-0002-1517-9627

Year of Publication

2019

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department

Plant and Soil Sciences

First Advisor

Dr. David Van Sanford

Abstract

Fusarium head blight (FHB) is a serious disease of wheat (Triticum aestivum) and other small grains; disease severity is affected by temperature and rainfall. This research comprised three studies: an artificially warmed experiment during 2016-2017, a morphology study and an FHB resistance screening study in 2015-2016, using approximately 250 wheat cultivars and breeding lines from programs in the eastern US. The location was the University of Kentucky Spindletop Research Farm in Lexington, KY. Higher levels of Fusarium damaged kernels and the toxin deoxynivalenol (DON) were observed in the warmed treatment compared to the control, and plant development was accelerated. In the FHB resistance screen, significant (p < 0.05) genotype differences for all traits were observed. A GWAS identified 16 SNPs associated with resistance and susceptibility, ranging from -2.14 to 4.01%. Three DON-associated SNPs reduced toxin levels by 3.2, 2.1, and 1.5 ppm. In the morphology study, negative correlations were observed among morphological and disease traits. Small effect SNPs were identified for all morphological traits, which might be useful in genomic selection; traits like spike length, spikelet number and inclination could be used in phenotyping. Response to warming indicates that existing resistance sources may be less effective in a warming climate.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2019.150

Funding Information

Funded by grants from USDA Triticeae Coordinate Agricultural Project, No. 59-0206-4-002 and the U.S. Department of Agriculture, through the US Wheat and Barley Scab Initiative under the agreement No. 59-0206-9-054.

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