Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 84-87). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 84-87). Also available on the Internet.

Thesis (Ph.D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xxi, 195 p.; also includes graphics. Includes bibliographical references (p. 184-195). Available online via OhioLINK's ETD Center

Thesis (M.S.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (month day, year) Includes bibliographical references.

Fusarium graminearum, the causative agent of Fusarium head blight, is an economically important pathogen of wheat (Triticum aestivum). Breeding Fusarium head blight (FHB) resistant wheat requires knowledge of the underlying genetic control of FHB resistance. Genetic parameters for FHB resistance and five related traits were estimated in three populations at two locations and in two years. Moderate broad sense heritabilities for FHB severity and Fusarium damaged kernels (FDK) were observed. Incidence of FHB and the toxin deoxynivalenol (DON) accumulation had low to moderate broad sense heritabilities. Correlations between FDK and severity and FDK and DON were moderate to high in the three populations and do support indirect selection for FHB severity or DON based on FDK data alone, but it is important to be cautious in years with a high disease pressure when FHB resistance could be masked. A cycle of among-family and within-family selection cycle was conducted in 2003. Actual selection gain was higher than predicted gain based on variance components in 2003 in the within-family selection study. One population had also a strong response for low DON in the among-family selection study. The observed results suggest that selection for FHB resistant genotypes could be achieved with a recurrent selection scheme. Along with conventional breeding, molecular techniques are being used in breeding for FHB resistance. A first genotypic screening of the three populations showed Population 2 had the presence of a resistance allele form the resistant Chinese cultivar Sumai 3. Although Populations 1 and 3 did not have the resistance allele, the results suggest other sources of resistance might be present in these two populations.

Fusarium graminearum, the causative agent of Fusarium head blight, is an economically important pathogen of wheat (Triticum aestivum). Breeding Fusarium head blight (FHB) resistant wheat requires knowledge of the underlying genetic control of FHB resistance. Two nine-parent diallel analyses were completed in greenhouse and field environments. Combining abilities, variance component ratios, and narrow sense heritabilities for FHB resistance and deoxynivalenol levels were calculated. Significant general and specific combining ability effects were observed. Resistance to FHB seems to be mostly controlled by additive genetic effects with some dominance noted in the field. Resistance noted in the greenhouse environment may not hold up in the field. Genetic parameters for FHB resistance and four related traits were estimated in three populations. Moderate to high broad sense heritabilities for FHB severity and Fusarium damaged kernels (FDK) were observed. Incidence of FHB had low to moderate broad sense heritabilities. Correlations between FDK and severity and FDK and incidence were moderate and low, respectively, and do not support indirect selection for FHB severity or incidence based on FDK data alone. Substantial predicted gains from family selection were observed and therefore selection of FHB resistant wheat lines should be based on family means and not individual selection.

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