Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Improving genomic resources for the study of invasiveness in Eurasian watermilofil (Myriophyllum spicatum) and their hybrids(Montana State University - Bozeman, College of Agriculture, 2021) Pashnick, Jeffrey John; Chairperson, Graduate Committee: Ryan Thum; This is a manuscript style paper that includes co-authored chapters.Genomics has revolutionized the way biologists ask fundamental questions about evolution. The thousands to tens of thousands of molecular markers generated through modern genomics increase the likelihood of detecting traits associated with a phenotype of interest. While genomics provides ever increasing evidence detecting these traits, they must be developed in each new system. Myriophyllum spicatum L. (Eurasian watermilfoil, EWM) and their hybrids with native Myriophyllum sibiricum Komorov (northern watermilfoil, NWM) are heavily managed aquatic plants in the United States. Genotypes both within and across these taxa and their hybrids can differ in their growth and herbicide response, prompting interest in determining which specific genotypes and genes will respond best to specific control tactics. However, because genotypes are unable to be distinguished by morphology, distinguishing genotypes requires molecular markers. EWM, NWM, and their hybrid are hexaploid (2n=6x=42) and developing these molecular markers requires accurately genotyping in a hexaploid with unknown chromosomal inheritance. The first manuscript of this dissertation empirically tested the genotyping information obtained from three commonly used molecular marker types, AFLPs, microsatellites, and GBS data. We found that while GBS markers have the lowest error rate, all molecular marker types provide the same genotype information. In the second chapter we used a mapping population, GBS data, and likelihood models to determine if watermilfoil was an allohexaploid, autohexaploid, or a mix between them. We found overwhelming evidence that watermilfoil is an allohexaploid across the genome. Finally, using the characteristics of each molecular marker type, the third chapter developed a cost-effective and information dense panel of microhaplotypes to genotype in watermilfoil. Microhaplotyping data can be shared across laboratories and promotes collaboration with weed managers by informing management with genetic information. Together, the work in this dissertation provides diploidized molecular markers and polyploid mode of inheritance to begin to connect genotype to herbicide response traits in watermilfoil.Item Effects of a barley chromosome 6H grain protein QTL on agronomic traits, malt quality traits, and stomatal control under two irrigation and nitrogen fertilization regimes(Montana State University - Bozeman, College of Agriculture, 2018) Mangel, Dylan J. L.; Chairperson, Graduate Committee: Andreas FischerCereal grain protein concentration (GPC) is an important quality parameter, with high GPC desirable when grain is used for food or feed, while low (typically below 12- 13%) GPC is needed when barley grain is used for malting. A major QTL controlling grain protein has previously been identified on barley chromosome 6H. Based on the comparison with a co-linear region on wheat chromosome 6B, the functional status of a gene coding for a NAC transcription factor (HvNAM-1) is responsible for controlling whole-plant senescence, nutrient remobilization from leaves to developing grains, and grain protein concentration. In this context, the purpose of this study was the analysis of the influence of a low- vs. a high-grain protein allele at this locus on barley agronomic and malting quality parameters in different genetic backgrounds. Integration of the low-protein allele stably lowered GPC by 1.6-1.8%, in both years and across all combinations of genetic backgrounds and management practices. Lines with the low-protein allele matured 1.4 to 2.5 days later, dependent on management, and had stably lower malt protein and diastatic power. Effects on additional agronomic and malt quality parameters including yield, test weight, percentage of plump kernels, free amino nitrogen and alpha-amylase activity were subtler and depended on the genetic background tested. Our data also provide important information on the influence of soil N and water availability on malt quality characteristics. Overall, use of the chromosome 6H low-grain protein allele stably lowered grain and malt protein levels without important negative influences on any of the tested agronomic and malt quality parameters, indicating its usefulness in the development of new malting barley germplasm. The studied chromosome 6H GPC QTL also controls expression of a gene coding for a glycine-rich RNA-binding protein (HvGR-RBP1) that may improve drought tolerance. Stomatal conductance and canopy thermal imaging assays did not show consistent effects of the allelic state of the GPC QTL on stomatal control. However, our data showed important correlations between stomatal conductance, canopy temperature depression and agronomic parameters including yield, demonstrating the value of the performed assays for variety selection and breeding.Item Identifying regions of conserved synteny between pea (pisum spp.), lentil (lens spp.), and bean (phaseolus spp.)(Montana State University - Bozeman, College of Agriculture, 2006) Moffet, Matthew Durwin; Chairperson, Graduate Committee: Norman Weeden.The identification of conserved synteny in legumes can facilitate many different types of gene discovery. Techniques like marker assisted selection and the candidate gene approach can benefit greatly by identifying conserved synteny and genes located within those regions. Both Pisum and Phaseolus have detailed linkage maps, but a limited number of markers have been located in both species. In the present study I mapped 21 genes in Phaseolus vulgaris, 16 of which had already been located on the Lens and Pisum sativum linkage maps, the markers were used to look for conserved synteny between Pisum, Lens and Phaseolus. In particular, I was able to target marker/gene-rich regions of pea linkage groups V and VII, as well as pea linkage group III, with Pisum STS markers and universally designed gene-specific markers already located on the pea linkage map.