Browsing by Subject "wheat"

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    2011 Progress Report on Grass Seed Production Research
    (2011) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2012 Progress Report on Grass Seed Production Research
    (2012) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2013 Progress Report on Grass Seed Production Research
    (2013) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2015 Progress Report on Grass Seed Production Research
    (2015) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2016 Progress Report on Grass Seed Production Research
    (2016) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2020 Progress Report on Grass Seed Production Research
    (2021) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    2021 Progress Report on Grass Seed Production Research
    (2022) Ehlke, Nancy; Vellekson, Donn; Grafstrom, Dave
    Summary of research on grass seed production conducted by the University of Minnesota.
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    Analysis of ergosterol in single kernel and ground grain by gas chromatography-mass spectrometry
    (Journal of Agricultural and Food Chemistry, 2006-05-11) Steffenson, Brian; Dong, Yanhong; Mirocha, Chester J
    A method for analyzing ergosterol in a single kernel and ground barley and wheat was developed using gas chromatography−mass spectrometry (GC-MS). Samples were saponified in methanolic KOH. Ergosterol was extracted by “one step” hexane extraction and subsequently silylated by N-trimethylsilylimidazole/trimethylchlorosilane (TMSI/TMCS) reagent at room temperature. The recoveries of ergosterol from ground barley were 96.6, 97.1, 97.1, 88.5, and 90.3% at the levels of 0.2, 1, 5, 10, and 20 μg/g (ppm), respectively. The recoveries from a single kernel were between 93.0 and 95.9%. The precision (coefficient of variance) of the method was in the range 0.8−12.3%. The method detection limit (MDL) and the method quantification limit (MQL) were 18.5 and 55.6 ng/g (ppb), respectively. The ergosterol analysis method developed can be used to handle 80 samples daily by one person, making it suitable for screening cereal cultivars for resistance to fungal infection. The ability for detecting low levels of ergosterol in a single kernel provides a tool to investigate early fungal invasion and to study mechanisms of resistance to fungal diseases.
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    Changing the Game: Using Integrative Genomics to Probe Virulence Mechanisms of the Stem Rust Pathogen Puccinia graminis f. sp. tritici
    (Frontiers in Plant Science, 2016-02-24) Steffenson, Brian; Figueroa, Melania; Upadhyaya, Narayana M; Sperschneider, Jana; Park, Robert F; Szabo, Les J; Ellis, Jeff G; Dodds, Peter N
    The recent resurgence of wheat stem rust caused by new virulent races of Puccinia graminis f. sp. tritici (Pgt) poses a threat to food security. These concerns have catalyzed an extensive global effort toward controlling this disease. Substantial research and breeding programs target the identification and introduction of new stem rust resistance (Sr) genes in cultivars for genetic protection against the disease. Such resistance genes typically encode immune receptor proteins that recognize specific components of the pathogen, known as avirulence (Avr) proteins. A significant drawback to deploying cultivars with single Sr genes is that they are often overcome by evolution of the pathogen to escape recognition through alterations in Avr genes. Thus, a key element in achieving durable rust control is the deployment of multiple effective Sr genes in combination, either through conventional breeding or transgenic approaches, to minimize the risk of resistance breakdown. In this situation, evolution of pathogen virulence would require changes in multiple Avr genes in order to bypass recognition. However, choosing the optimal Sr gene combinations to deploy is a challenge that requires detailed knowledge of the pathogen Avr genes with which they interact and the virulence phenotypes of Pgt existing in nature. Identifying specific Avr genes from Pgt will provide screening tools to enhance pathogen virulence monitoring, assess heterozygosity and propensity for mutation in pathogen populations, and confirm individual Sr gene functions in crop varieties carrying multiple effective resistance genes. Toward this goal, much progress has been made in assembling a high quality reference genome sequence for Pgt, as well as a Pan-genome encompassing variation between multiple field isolates with diverse virulence spectra. In turn this has allowed prediction of Pgt effector gene candidates based on known features of Avr genes in other plant pathogens, including the related flax rust fungus. Upregulation of gene expression in haustoria and evidence for diversifying selection are two useful parameters to identify candidate Avr genes. Recently, we have also applied machine learning approaches to agnostically predict candidate effectors. Here, we review progress in stem rust pathogenomics and approaches currently underway to identify Avr genes recognized by wheat Sr genes.
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    The Effects of Diverse Dietary Interventions on Markers of Colon Cancer Risk in Carcinogen-Treated Rodents
    (2023-12) Bailey, Allison
    Colon cancer, a leading cause of cancer-related deaths worldwide, is largely preventable through lifestyle modifications including diet. While epidemiologic evidence associates foods rich in phytochemicals and dietary fiber with a reduced risk of cancer, the chemopreventive efficacy of specific dietary interventions to reduce colon cancer risk is still uncertain. In four studies, this thesis aims to explore the effects of three dietary interventions (red wheat, apiaceous and cruciferous vegetables, and prebiotic dietary fiber) on colon cancer risk in rodents and to characterize the effectiveness of the Total Western diet as a rodent background diet for colon cancer and inflammatory disease models. The first study used a mouse model to explore the effects of different wheat classes and milling fractions on colon cancer prevention. However, the results were inconclusive. Ultimately this mouse model was unsuitable due to challenges with the carcinogen dosage and toxicity, tissue incompatibility with a major biomarker assay, and the limited volume of tissue available for study due to a mouse’s small size. The second study continued this work using a rat model and added the variable of a comparison of background diets: a standard, optimized rodent diet (AIN-93G) or a newer diet based on the typical Western diet (Total Western Diet; TWD). We found some evidence that whole red wheat may reduce CC risk, but only with the TWD background diet, indicating that TWD may be a better background diet for CC rodent models. The third study examined the effects of apiaceous and cruciferous vegetables on colonic inflammation and compared TWD with the Diet Induced Obesity (DIO) model, which uses the same micronutrient concentrations as the AIN-93G diet. Vegetables decreased colon inflammation, but only with the TWD background diet, further supporting its use in modeling lifestyle diseases. The final study examined the effects of prebiotic dietary fibers, including the novel prebiotic fiber polylactose, on CC risk. We found no evidence that polylactose decreases CC risk, but limited evidence that polydextrose decreases CC risk indicates the need for further research in this area. Taken together, these studies expand our understanding of the effect of diet on CC risk by highlighting the detrimental role of mild micronutrient deficiency modeled by the TWD and providing modest support for consuming nutrient rich foods such as whole red wheat, apiaceous and cruciferous vegetables, and prebiotic fibers to reduce CC risk.
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    Herbicide and Nonherbicide Injury Symptoms on Spring Wheat and Barley
    (St. Paul, MN: University of Minnesota Extension Service, 1998) Cavanaugh, Kevin J.; Durgan, Beverly R.; Zollinger, Richard K.; Selberg, Wayne A.
    Covers the topic of wheat and barely injury in two parts: herbicide injury symptoms and nonherbicide injury symptoms.
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    Introgression of leaf rust and stripe rust resistance from Sharon goatgrass (Aegilops sharonensis Eig) into bread wheat (Triticum aestivum L.)
    (Genome, 2014) Steffenson, Brian; Millet, E.; Manisterski, J.; Ben-Yehuda, P.; Distelfeld, A.; Deek, J.; Wan, A.; Chen, X.
    Leaf rust and stripe rust are devastating wheat diseases, causing significant yield losses in many regions of the world. The use of resistant varieties is the most efficient way to protect wheat crops from these diseases. Sharon goatgrass (Aegilops sharonensis or AES), which is a diploid wild relative of wheat, exhibits a high frequency of leaf and stripe rust resistance. We used the resistant AES accession TH548 and induced homoeologous recombination by the ph1b allele to obtain resistant wheat recombinant lines carrying AES chromosome segments in the genetic background of the spring wheat cultivar Galil. The gametocidal effect from AES was overcome by using an “anti-gametocidal” wheat mutant. These recombinant lines were found resistant to highly virulent races of the leaf and stripe rust pathogens in Israel and the United States. Molecular DArT analysis of the different recombinant lines revealed different lengths of AES segments on wheat chromosome 6B, which indicates the location of both resistance genes.
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    Misfits of wheat stem rust resistance-­‐ Unusual solutions to a consistent problem
    (2016-12) Briggs, Jordan
    Rust fungi include some of the most economically damaging pathogens of wheat. They are notorious for their ability to quickly spread in susceptible host populations and greatly reduce grain yield potential and quality when managed improperly. Puccinia graminis f. sp. tritici (Pgt), the causal agent of wheat stem rust, can cause yield losses exceeding 50%. Stem rust is controlled in the U.S.A. using several methods including the introduction of genetic resistance, selection for earlier maturing varieties, removal of the alternate host Berberis vulgaris, and the application of fungicides. Subsequently, epidemics of stem rust causing greater than 10% yield losses have not been observed in the U.S.A. since the mid 1950’s. Together, removal of B. vulgaris from wheat growing regions and the introduction of genetic resistance have accounted for much of the control of stem rust. Genetic resistance remains the dominant method of controlling stem rust in regions where removing B. vulgaris is not applicable. In more recent years, races of Pgt have been identified that overcome most widely deployed resistance genes. In 1999 race TTKSK was identified in Uganda that overcame stem rust resistance gene Sr31. Following deployment of Sr24 in Kenya, further selection for virulence resulted in the identification of race TTKST, then TTTSK (Sr36 virulence), and more recently TTKTT and TTKTK (SrTmp virulence). Major resistance genes have continually proven to not provide a durable form of resistance to wheat stem rust. Some resistance genes however have proven the test of time and remain effective to date. These resistance genes include Sr2, Lr34, Lr46, and Lr67. Each gene functions in an additive, minor-effect, and in some cases recessive manner, atypical of standard major genes, and provides and/or enhances resistance to multiple diseases including stem rust, leaf rust, stripe rust, and powdery mildew. Additionally Lr34 and Lr67 do not have the NB-LRR protein domains consistent with major genes. Durable genetic resistance to stem rust may require sources of resistance that deviate from standard mechanisms. This dissertation describes such sources of resistance. SrTm4 is a major gene identified in Triticum monococcum that functions in a recessive manner, is broadly effective, and elicits a mesothetic (intermediate-effect) infection type. The adult plant resistance observed in ‘Morocho Blanco’ was found to have two underlying QTL, Qsr.cdl.2BS.2 and Qsr.cdl.6AS.1. These two loci comprise much of the adult plant resistance in ‘Morocho Blanco’ and exhibit interactions with environment or pathogen race. The Sr12 mutants created in this dissertation were made to characterize the disease reducing capabilities of Sr12: a recessive, race specific major gene that co-locates with adult plant resistance to Sr12 virulent races. Lastly, this dissertation also describes the identification of putative susceptibility genes for rust pathogens in barley, maize, soybean, and Brachypodium distachyon. The putative susceptibility gene in B. distachyon was tested with a T-DNA insertion mutant and exhibits enhanced rust resistance, however, may be linked to changes in overall plant growth and development. Each source of rust resistance defies standard systems of characterization and includes some traits that are less desirable along with their resistance capabilities, for example: unstable expression due to environmental interactions, race specificity, or recessive gene action. However, the benefit of these sources of stem rust resistance may compensate for their less desirable traits.
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    Pathovar identification and genetic diversity of Xanthomonas translucens strains isolated from weedy grasses and cultivated wild rice in Minnesota
    (2019-09) Ledman, Kristi
    Bacterial leaf streak (BLS) of wheat, caused by Xanthomonas translucens pv. undulosa, has been prevalent in Minnesota wheat fields for the past decade. Infested seed and crop debris can serve as inoculum for subsequent crops. Weeds are also considered a potential inoculum source, but little is known about specific pathovars and genetic diversity among strains of X. translucens from these different hosts. The objectives of this study were to isolate X. translucens from poaceous weeds and cultivated wild rice in Minnesota, determine pathogenicity of these strains on wheat and barley, assess phylogenetic relationships and genetic diversity of strains using multilocus sequence analysis (MLSA) and typing (MLST) of four housekeeping genes (rpoD, dnaK, fyuA, and gyrB), and evaluate the efficacy of loop-mediated isothermal amplification (LAMP) assays designed to identify X. translucens pathovars that cause BLS on small grains. Bacteria were isolated from 157 plant samples, representing 12 poaceous hosts collected in and around commercial fields of wheat and wild rice. Strains exhibiting characteristic colony morphology on Wilbrink’s medium were purified and evaluated further. The majority (87/134) of Xanthomonas strains were predicted to be X. translucens by 16S rDNA sequencing. A subset (51) of the strains predicted to be X. translucens were infiltrated into leaves of wheat and barley seedlings and found to cause disease. Eight of these strains were also tested in the field and likewise caused disease on wheat and barley. Phylogenies from MLSA show that strains from weedy grasses and wild rice are closely related to known X. translucens pathovars, most commonly X. translucens pv. undulosa. The findings suggest that poaceous weeds and cultivated wild rice have potential to serve as reservoirs of inoculum for the bacterial pathogen inciting BLS of wheat.
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    Sample 360 video for the analysis of plant movement
    (2018-09-12) Susko, Alexander, Q; susko004@umn.edu; Susko, Alexander, Q; University of Minnesota Oat Breeding and Genetics Lab
    Violent movement of cereal crop stems can lead to failure under high winds. Known as lodging, this phenomenon is particularly severe in cereal crops such as oat, barley, and wheat, and contributes to yield and economic losses. Quantifying the movement of cereal crops under field wind stress could aid in the breeding and selecting of lodging resistant cereals. We present a method to quantify the wave like movement of cereal crop rows in a high throughput fashion under field wind conditions. By analyzing pre-defined regions of hemispherical 4K resolution video, we obtain a time varying color signal of wind induced stem and canopy movement. Bandpass filtering is applied to the color signals to filter out changes in lighting due to sunlight changes, enabling comparisons across different lighting conditions. Peaks are then identified in the signal, and the distance in frames to the next peak as well as the absolute area under the curve between peaks is recorded. The distributions of distances to adjacent peaks (expressed as frequencies) are recorded and the area within a defined frequency bin is summed to get an approximation of the frequency and amount movement. We applied this method to analyze the wind induced movement of 16 cereal cultivars planted in a randomized complete block design on 5 different windy days. We detected significant differences in the mean frequency and amplitude within 0.2 Hz frequency bins among 16 cereal cultivars, with mean frequencies ranging between 1.24 and 1.53 Hz. This method quantifies the frequency and amplitude of movement in cereal varieties at high throughput in the field, and shows promise for characterizing the physiological basis for differences in cereal movement and lodging resistance.
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    The Small Grains Field Guide
    (St. Paul, MN: University of Minnesota Extension Service, 2005) Wiersma, Jochum J.; Ransom, Joel K.
    This book is a guide for the production of wheat, barley, and oats in Minnesota and North Dakota. Contains 10 sections: Agronomic Management, Crop Growth and Staging, Fertility Management, Photographs, Pesticide Management, Weed Control, Disease and Pest Management, Harvest and Storage Management, Wheat Marketing, and Useful Internet Information Resources.
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    Studies On Wheat Resistance To UG99
    (2010-10) Rouse, Matthew
    Wheat stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt) has historically been a devastating disease of wheat. In 1998, a race of Pgt was detected in Uganda that is virulent to the majority of wheat cultivars being grown. This new race, commonly referred to as Ug99, was characterized as race TTKSK based upon the North American stem rust differentials. Race TTKSK has recently spread throughout eastern and southern Africa, and into the Middle East. Data suggest that Ug99 can alternatively be described as Pgt race PTKSK, based upon demonstrated avirulence to stem rust resistance gene Sr21. Accessions of wild relatives of wheat, Triticum monococcum, T. urartu, and Aegilops tauschii were screened with Pgt race TTKSK. Crosses among resistant and susceptible accessions of T. monococcum led to the characterization of two new stem rust resistance genes effective to Pgt-TTKSK. Preliminary screening of 700 accessions of spring wheat led to the identification of 88 accessions with resistance to Ug99. Examination of the genetics of resistance in one of these accessions, SD 1691, identified Sr28 as conferring a high level of resistance. Molecular markers linked to Sr28 were identified on chromosome arm 2BL. Examination of the genetics of resistance in Gabo 56 indicated the presence of a single dominant gene. This gene was temporarily designated as SrGabo56 and mapped on chromosome arm 2BL. Segregation of resistance in the progeny of the cross between SD 1691 and Gabo 56 indicated that Sr28 and SrGabo56 are linked. Characterization of the genetics of resistance to Pgt-TTKSK in synthetic wheat TA4152-37, resulted in the identification of Sr13 in TA4152-37. Molecular markers linked to Sr13 in hexaploid wheat were identified on chromosome arm 6AL. Overall, 3 new stem rust resistance genes effective to Pgt-TTKSK were identified. Molecular markers linked to SrGabo56, Sr13, and Sr28 were described. The identification of markers linked to multiple stem rust resistance genes will facilitate the combination of these genes in breeding lines. The identification of the new sources of resistance to Pgt-TTKSK will provide plant breeders with additional tools to protect wheat from this dangerous race.
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    Videos for Cereal Crops in a Wind Tunnel
    (2019-05-10) Susko, Alexander Q; susko004@umn.edu; Susko, Alexander; University of Minnesota Saint Anthony Falls Laboratory
    92 videos analyzed for "A wind tunnel analysis of cereal drag coefficients and stem bending". Scripts for analysis, including data obtained for the videos, is available online at https://github.com/Hortus/windtunnel_video_analysis.
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    Wheat and Barley Drying
    (St. Paul, MN: University of Minnesota Extension Service, 1992) Wilcke, William F.; Hellevang, Kenneth J.
    This fact sheet gives recommendations for drying wheat or barley that has been harvested at high moisture content.
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    Wheat and Barley Storage
    (St. Paul, MN: University of Minnesota Extension Service, 1992) Wilcke, William F.; Hellevang, Kenneth J.
    This fact sheet describes how to select and manage grain storage equipment to reduce losses to mold and insects, and reduce exposure to mold spores and pesticides.