Phytophthora sojae, the causal organism of stem and root rot, and <i>Soybean mosaic virus</i> (SMV) cause two of the most highly destructive diseases of soybean (<i>Glycine max</i> L. Merr). <i>P. sojae</i> can be managed either through deployment of race-specific resistance or through quantitative resistance termed partial resistance. In the current study, partial resistance to <i>P. sojae</i> was mapped in an interspecific recombinant inbred line (RIL) population of <i>Glycine max</i> by <i>Glycine soja</i>. One major quantitative trait loci (QTL) on molecular linkage group (MLG)-J (chromosome 16) and two minor QTL on MLG-I (chromosome 20) and -G (chromosome 18) were mapped using conventional molecular markers. Additionally, partial resistance to <i>P. sojae</i> was mapped in the same RIL population using single feature polymorphism (SFP) markers that further fine mapped the <i>P. sojae</i> QTL and identified potential candidate genes contributing to resistance. In a separate study, race-specific resistance was characterized in PI96983 discovering a potentially new allele of <i>Rps4</i> on MLG-G. Finally, using the newly available whole-genome shotgun sequence of soybean, <i>Rsv4</i> conferring resistance to strains of SMV known in the US, was localized to an approximately 100 kb region of sequence on chromosome 2 (MLG-D1B). Newly designed PCR-based markers permit for efficient selection of <i>Rsv4</i> by breeding programs. Identified candidate genes for <i>Rsv4</i> are discussed. Genomic resources developed in all of these studies provide breeders the tools necessary for developing durable resistance to both SMV and <i>P. sojae</i>. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/79598 |
| Date | 04 May 2009 |
| Creators | Tucker, Dominic M. |
| Contributors | Crop and Soil Environmental Sciences, Saghai-Maroof, Mohammad A., Tolin, Sue A., Jelesko, John G., Rainey, Katy Martin, Tyler, Brett M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation, Text |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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