Degree

Doctor of Philosophy (PhD)

Department

School of Plant, Environmental, and Soil Sciences

Document Type

Dissertation

Abstract

Fusarium head blight (FHB), caused by the fungus Fusarium spp., is a disease that attacks several grass species, including wheat. Wheat variety AGS 2060 has remained moderately susceptible to FHB and is regularly found in pedigrees of resistant breeding lines. Quantitative trait loci (QTL) mapping was conducted to find sources of resistance to FHB in AGS 2060. A 90K SNP chip was used to genotype a double haploid mapping population produced from a cross between wheat varieties AGS 2060 and AGS 2035. There were highly significant differences between lines in the population for Fusarium damaged kernels (FDK) rating and deoxynivalenol (DON) content across all locations and years. QTL analysis was conducted individually for each combination of location and year (model) in the experiment for resistance to FDK and DON. The 15 QTLs detected were distributed over 13 chromosomes. The QTL on chromosome 2A was the most consistently detected (5 models) in the experiment and provided resistance to both DON and FDK. The best location to evaluate for resistance was Winnsboro in 2019, where 11 QTLs where detected.

Fhb1 is widely considered as the most important quantitative trait locus (QTL) for genetic resistance to FHB. This study was conducted to evaluate the effect of Fhb1 on FHB infection, FDK, DON, and grain yield in a soft red winter wheat biparental family inoculated with Fusarium spores collected in Louisiana. Wheat lines at the F4:5 generation from a cross containing a Fhb1 parent were observed to segregate for FHB, FDK, and DON. F4:6 lines were tested as head rows in misted nurseries as well as in replicated yield plots. Fhb1 had a significant effect on both FDK and DON content (P<0.0001); however, there was no significant difference for yield (P=0.1389) and test weight (P=0.8273).

Date

11-1-2019

Committee Chair

Harrison, Stephen

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