Browsing by Subject "Wheat"

Now showing 1 - 20 of 26
  • Thumbnail Image
    Item
    Bacterial Leaf Streak of Wheat: Inoculation Methods and Epidemiology
    (2019-04) Stanton, Justin
    Xanthomonas translucens pv. undulosa, is the causal organism of bacterial leaf streak (BLS) in wheat (Triticum aestivum). Experiments were conducted to examine the influence of the environment in disease spread from inoculated central points. Inoculations at the three, four, and five leaf, booting, and heading growth stages, indicated that early inoculations produced higher and more consistent levels of BLS than inoculations made at later stages. Warm temperatures favored higher BLS severities in all experiments. The spread of BLS from the inoculated center point was promoted by wind speeds greater than or equal to 3 m/s during periods of leaf wetness. In a second experiment, five trials were conducted to evaluate methods of inoculation. Four methods were evaluated using either a CO2-powered backpack sprayer or a gas-powered mist blower. Severity and uniformity were improved using methods with attachments to the gas-powered mist blower in comparison to the other treatments.
  • Thumbnail Image
    Item
    Characterization and quantitative trait loci (QTL) mapping of Fusarium head blight resistance-related traits in the Japanese wheat landrace, PI 81791 (Sapporo Haru Komugi Jugo)
    (2010-04) Quirin, Edmund Andrew
    Fusarium head blight (FHB) is a destructive disease of wheat (Triticum aestivum L.). Infection by Fusarium graminearum affects yield and grain quality traits that can lead to substantial economic losses. Developing resistant cultivars has been a major objective of plant breeders for controlling FHB. The objective of this study was to assess FHB resistance in the Japanese landrace, PI 81791 (Sapporo Haru Komugi Jugo), a line that does not possess the widely used Fhb1 QTL for type II resistance. A population of 150 recombinant inbred lines (RILs) was developed from a cross between this genotype and the susceptible variety, Wheaton, and was assessed for several resistance-related traits, including type I and II resistance, post-harvest grain traits, and agronomic traits in four field environments in Minnesota. Type II resistance was also assessed in two greenhouse environments. The RILs were genotyped using 377 microsatellite markers. Composite interval mapping detected QTL for resistance traits on chromosomes 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6A and for heading date and height on 1B, 2D, 3B and 4D. The resistance QTL on chromosomes 2B, 3B, and 3D explain the largest amount of variation observed for many of the resistance traits analyzed with alleles being inherited from PI 81791. The QTL on chromosome 3B in the interval of Xbarc229 – Xgwm383b appears to be a major novel resistance locus that explains 7 – 21% of the variation observed for various resistance traits. Similar QTL regions to those on chromosome 2B in the interval of Xgwm639b – Xwmc339 and chromosome 3D in the interval of Xwmc533a – Xwmc656 have been previously reported, supporting their use for FHB resistance breeding. Major resistance QTL were also identified on chromosomes 4A, associated with Xbarc233, and 4D, which is associated with the semi-dwarfing gene, Rht-D1. However, these QTL are likely associated with increased susceptibility from PI 81791 and Wheaton, respectively. Additional type II resistance QTL were identified on 3A in greenhouse environments, explaining as much as 23.2 and 15.8% of the phenotypic variation observed.
  • Thumbnail Image
    Item
    Combating Fusarium Head Blight Resistance in Wheat with Genomic Selection and Computer Vision Technology
    (2022-01) Adeyemo, Emmanuel
    Fusarium head blight (FHB), primarily caused by Fusarium graminarum, Schwabe, is a devastating fungal disease that limits wheat production globally and can significantly reduce yield and grain quality. At the University of Minnesota, screening for FHB begins at the F5 stage and continues annually until the line is released as a cultivar. Before implementing genomic selection at the F5 stage in 2016, we evaluated ~ 3,000 F5 lines annually in field nurseries. The use of genomic selection allowed the prediction of untested lines with a training population of 500 lines selected by pedigree information. The first study showed that a set of 200 lines selected by genomic relationship led to predictive abilities of up to 0.49, whereas a larger, randomly selected subset of 500 F5 lines had a maximum predictive ability of 0.34. While the addition of parents also led to increased predictive abilities, the increments were not significant in most cases. The second study examined the merit of incorporating available germplasm into our existing genomic selection pipeline. We observed that training populations that contained historical data were less useful while those that included a subset of 200 F5 lines selected by genomic relationship, were more effective for predicting FHB. The third study demonstrated the use of computer vision to estimate the percentage of kernels damaged by Fusarium. We utilized 85 samples containing five check cultivars with varying levels of FHB susceptibility and maturity and achieved an accuracy of 90%. Additional studies should be done to assess the utilization of this technology among our experimental lines.
  • Thumbnail Image
    Item
    Crop Sequence Effects of Pulse Crops and Agronomic Research on Lupine
    (Minnesota Agricultural Experiment Station, 1984) Robinson, R.G.; Rabas, D.L.; Smith, L.J.
  • Thumbnail Image
    Item
    Deciphering lodging resistance in oat and other cereal crops
    (2019-08) Susko, Alexander
    Lodging impedes the successful cultivation of oat and other cereal crops in the upper midwestern United States. Lodged cereals not only possess reduced grain yields, but also decreased grain quality. This dissertation first conceives of a camera system to capture plant movement in the wind in the field via a 360-degree field of view camera, followed by a video analysis pipeline to quantify the frequency and amplitude of cereal stem movement under varying wind conditions in the field. The natural oscillating frequencies and amplitudes of stems were dependent on wind speeds and at the cultivar, crop level. Nonetheless, the substantial environmental effects in the field that induce lodging make discovering specific morphologies that confer lodging resistance difficult. Next, in seeking to better identify promising morphological targets for breeding and selecting lodging resistance in cereal crops, a diverse panel of 38 cereal cultivars (oat, wheat, barley) were subjected to replicated testing in a wind tunnel. Wind tunnel testing revealed that a cereal ideotype consisting of low total biomass, high stem strength, and high stem elasticity should confer increased lodging resistance. A field study using the camera system to quantify aspects of plant movement and correlated these phenotypes with physical plant traits is presented next, which indicated that patterns of plant movement are spatially independent in a randomized complete block design of 16 cereal cultivars and that the relationships between plant height, heading date, and plant movement vary among the major cereal crops. Finally, a GWAS and QTL validation study is presented on lodging in oat, which revealed significant marker trait associations for plant height, heading date, and stem snapping, though only QTL for plant height and heading date were successfully validated in derived biparental populations.
  • Thumbnail Image
    Item
    The effect of intake of whole grain and whole grain components on type 2 diabetes in rats.
    (2012-02) Youn, Moon Yeon
    Consumption of whole grains has been associated with reduced risk of type 2 diabetes epidemiologically. However, studies of the effect of individual whole grains on the development of type 2 diabetes are lacking. The objective of this research was to examine the effect of consumption of whole grains and a processed whole grain component on type 2 diabetes in diabetic rats. The first study was designed to investigate the effect of various whole grains consumption on diabetic control and progression in an animal model of type II diabetes, the Goto-Kakisaki (GK) rat. In this study, whole grain consumption showed only slight improvements in glucose control and insulin resistance early in the progression of diabetes, improvements which were lost with time, and no improvement in a marker of oxidative stress. The slight effect of whole grain consumption on slowing the progression of type 2 diabetes may be due to poor bioavailability of nutrients and phytochemicals. Thus, it was hypothesized that consumption of a processed whole grain ingredient with increased bioavailability of nutrients and phytochemicals might improve the diabetic state. The purpose of the second study was to examine the effect of processed wheat bran consumption on metabolic parameters related to diabetes and obesity in an animal model of type 2 diabetes with obesity, the Zucker diabetic fatty (ZDF) rat. The consumption of processed wheat bran had highly beneficial effects on the diabetic state, including decreasing the insulin response after a meal, decreasing visceral fat pad weight, insulin resistance, and plasma and liver cholesterol, and increasing bile acid excretion. The finding of correlations between ferulic acid, the major phenolic in wheat, in plasma and urine and metabolic parameters related to diabetes suggests that increased bioavailability of ferulic acid is responsible for the improvements seen in these parameters. In conclusion, whole grain intake provided a modestly beneficial effect on the development of type 2 diabetes. However, processing of a whole grain component, wheat bran, to increase the bioavailability of active compounds in the bran resulted in highly significant improvements in the diabetic state in an animal model of type 2 diabetes with obesity.
  • Thumbnail Image
    Item
    The effect of whole wheat and wheat milling fractions on metabolic parameters of adiposity, glucose control, and lipid metabolism using a rat model of obesity with type 2 diabetes
    (2014-01) Dos Santos, Ana
    Obesity prevalence is at an all-time high, with 1 in 3 Americans now classified as obese (1). Obesity is a debilitating condition that is associated with various co-morbidities, including type 2 diabetes (T2D), cardiovascular disease, pulmonary dysfunction, gastrointestinal disease, various cancers, and osteoarthritis. T2D is one of the most significant co-morbidities of obesity, as it often leads to other diseases such as non-alcoholic fatty liver disease (NAFLD) and hyperlipidemia. There are now 347 million people worldwide with T2D (2).The incidence of newly diagnosed cases of T2D in America is at its highest of 1.9 million per year and, according to the American Diabetes Association, and if the trend continues, 1 in 3 Americans will have diabetes by the year 2050 (3). There are many factors that increase the risk of developing T2D, some which include being overweight and physically inactive, having a genetic predisposition, and high blood pressure. In addition, there are complications that develop gradually over a period of time during T2D if blood glucose sugar levels are not properly controlled. Long-term poor glucose control puts patients at a higher risk for complications such as cardiovascular disease (CVD), neuropathy, nephropathy, and retinopathy.Obesity and diabetes are having a substantial impact on the economic state of the health care system. The total estimated cost of diagnosed diabetes in 2012 was $245 billion. This includes $176 billion in direct medical costs and $69 billion in reduced productivity, encompassing lower labor force participation from chronic disability and premature mortality (4). In addition to the economic burden, there are substantial intangible costs, such as a reduced quality of life for those people with diabetes, and often for their families and friends as well. Several epidemiological studies suggest that whole grain consumption is associated with a lower risk of obesity and T2D. Whole grain consumption has been found to have an inverse association with fat mass and insulin resistance in both humans and rats, possibly through several different mechanisms, involving mechanical, hormonal, and anti-inflammatory processes. The mechanical mechanism focuses on alterations in caloric density and absorption of nutrients, the hormonal mechanism on changes in hormone synthesis and secretion due to nutrient availability, and lastly, anti-inflammatory and anti-oxidative components in the whole grain. However, it is unclear which milling fraction of the whole grain, the bran, germ, or endosperm, may be responsible for these health benefits. Therefore, the aim of this study was to examine the effects of whole wheat and wheat milling fractions, specifically bran, germ, and endosperm, on glucose control, insulin resistance, fatty liver, and adiposity using an animal model of obesity with T2D, the Zucker Diabetic Fatty (ZDF) rat. Male ZDF rats were fed either a cornstarch-based diet (AIN-93G; obese control ), or diets containing 64% whole wheat flour, 54% refined wheat, 9.4 % wheat bran, 1.6% normal wheat germ, or high 15% wheat germ for 5 weeks. Lean ZDF littermates fed a standard AIN-93G diet served as a negative control. All animals were fed ad libitum. The refined wheat, wheat bran, and wheat germ were present in the diets in the same concentration as would be found in the whole wheat diet. The high wheat germ diet had amounts of germ 10 times that of the normal wheat germ diet. It was found that after 5 weeks, the whole wheat, refined wheat, and high and normal wheat germ groups all showed a significant improvement (p<0.05) in area under the curve during glucose and insulin tolerance tests. There were no differences in body weight or fat pad weight among the ZDF groups; however, there was a significant difference (p=0.031) in fat mass % between the whole wheat group and the obese control. The whole wheat group and all wheat fraction groups decreased the concentration of liver lipids compared to the obese control, and the bran and germ groups also had lower liver cholesterol concentration. Only the whole wheat group had a significantly lower cecum pH (p<0.0001) and greater cecal weight (p<0.0001) compared to the obese control, indicating greater fermentation of the diet. There were no significant differences in plasma adiponectin and resistin levels among the ZDF diet groups. In conclusion, the results of this study suggests that none of the wheat milling fractions stand out as responsible for the metabolic effects seen with consumption of whole wheat and that individual milling fractions of wheat are just as effective in improving insulin resistance and fatty liver as whole wheat.
  • Thumbnail Image
    Item
    The effects of wheat class and processing on markets of colon cancer risk in carcinogen-treated rats.
    (2009-02) Islam, Ajmila
    A previous study in this laboratory found that hard red wheat is more effective than soft white wheat in reducing colon cancer risk, regardless of processing state, based on fewer aberrant crypt foci (ACF), a morphological marker of colon cancer risk. Here we examined the effect of wheat class (red vs. white) and processing (whole vs. refined) on reducing markers of colon cancer risk during the early and late promotion stage of colon cancer development. Rats adapted to a basal diet were treated twice with the colon-specific carcinogen, dimethylhydrazine (DMH). After the last dose of carcinogen, rats were divided into either the basal diet or the wheat flour-based diet groups. Both hard red and soft white wheat flour significantly reduced morphological markers such as ACF, and sialomucin producing ACF (SiM-ACF), an ACF with greater tumorigenic potential, compared to the basal diet. These reductions occurred equally with whole and refined wheat. Both hard red and soft white wheat diets significantly reduced a biochemical marker of risk, beta-catenin accumulated crypts (BCAC), compared to the basal diet, but hard red wheat did so to a greater degree. Only hard red wheat significantly reduced a marker of stem cells mutation, metallothionein positive crypts, compared to soft white wheat. Hard red wheat caused regression of ACF, suggesting it can reduce the risk level of colon cancer. Overall, hard red wheat reduced colon cancer risk more than soft white wheat, regardless of processing state. The differences between wheat flours were greater in the late promotion stage.
  • Thumbnail Image
    Item
    Factors affecting Fusarium head blight development and trichothecene accumulation in fusarium-infected wheat heads.
    (2010-06) Gautam, Pravin
    Fusarium head blight (FHB), primarily caused by Fusarium graminearum Schwabe, is an economically important disease as it results in yield loss and quality losses of infected grain and the accumulation of mycotoxins produced by the invading fungus. Environmental factors, host genetics, and isolate aggressiveness impact FHB development and subsequently trichothecene production and accumulation. Though it is well established that moisture around anthesis promotes FHB development and trichothecene accumulation, the role of moisture, either in the form of rainfall or mist-irrigation during the period from anthesis to harvest has been largely overlooked. A three year field experiment was conducted in 2006, 2007 and 2008 to examine the influence of environmental factors, especially moisture, host resistance, and pathogen variation with respect to mycotoxin production capacity and pathogen aggressiveness, on infection, FHB development and mycotoxin production and accumulation in planta. In mature harvested grain FHB severity, visually scabby kernel (VSK) and mycotoxin concentration were significantly higher in Wheaton (FHB susceptible) than in the other two cultivars examined, Alsen and 2375. Although FHB severities were not significantly different in plots receiving different durations of mist-irrigation, VSK were significantly lower in the treatments receiving the least amount of mist-irrigation (14 DAI) than for treatments receiving mist-irrigation for longer periods, suggesting that extended periods of moisture promote disease development. DON concentration in harvested grain was, however, significantly lower in the treatment receiving the longest duration of mist-irrigation than those treatments receiving less water. In the whole head samples, which were collected 0, 7, 11, 14, 21, 28 and 41 days after inoculation, DON and other trichothecenes either declined with increased durations of mist-irrigation or remained low while water was being applied by the misting system. However, trichothecene accumulation was observed to increase after the cessation of mist-irrigation, with increases being most pronounced for the treatments with shorter mist-irrigation periods. The largest reduction in DON observed as a result of extended mist-irrigation periods was seen in the susceptible cultivar Wheaton. The influence of host resistance and pathogen variation on infection, FHB infection, disease development and mycotoxin accumulation in planta was examined in the series of greenhouse experiments utilizing point and spray inoculations. The levels of FHB severity and mycotoxins were higher in spray inoculated experiment than point inoculation in all cultivars examined. Wheaton (FHB susceptible) had the highest FHB severity and levels of mycotoxins. Alsen (moderately resistant to FHB) had significantly lower FHB severities, DON, 15-ADON, 3-ADON and NIV than either 2375 or Wheaton. Though there were no significant differences in initial infection among cultivars examined, Alsen had reduced spread of FHB symptoms from initial infection presumably due to type II resistance. DON production did not peak in all treatments, but where evident, the peak was earlier in 2375 (11 dai) than Alsen and Wheaton (21 or 14 dai). Multiple peaks and declines in DON levels were also evident. The performance of isolates was highly variable, though generally isolates Butte86Ada-11 and B63A were the most aggressive isolates and 49-3 and B45A were the least. The impact of free moisture, such as that from irrigation systems or rainfall, on mycotoxin accumulation was evaluated in greenhouse experiments. Despite the similar levels of FHB severity observed, the levels of mycotoxins were significantly less in the plants that received a single six hour wetting treatment compared to the respective control. The loss of DON and other mycotoxins was evident in all cultivars examined. Further, DON and 15-ADON were detected in run-off water. The results of these studies suggest that the availability of free moisture such as from mist-irrigation or rainfall may increase FHB severity and VSK, although DON and other trichothecene concentrations may be concomitantly reduced. Leaching appears to contribute to reductions in DON following wetting events.
  • Thumbnail Image
    Item
    The Feeding value of wheat. Press bulletin no.14.
    (University of Minnesota. Agricultural Experiment Station., 1901-10-07) University of Minnesota, Agricultural Experiment Station
  • Thumbnail Image
    Item
    Genetics of Rust Resistance in a Wheat Nested Association Mapping Population
    (2017-10) Manan, Fazal
    Wheat is an important food crop in many parts of the world, but its genetic diversity has been eroded due to intense selection in breeding programs. To increase genetic diversity in the Minnesota wheat breeding program, a nested association mapping population was developed by crossing 25 exotic accessions selected from the USDA-ARS Spring Wheat Core Collection with RB07, a Minnesota cultivar selected as the common parent because it has wide adaptation in the region. Virulent races of the stem rust (Puccinia graminis f. sp. tritici, Pgt), leaf rust (P. triticina, Pt), and stripe rust (P. striiformis f. sp. tritici, Pst) pathogens threaten the wheat crop in the region. Thus, the objective of this thesis was to elucidate the genetics of rust resistance in select families of the Minnesota Nested Association Mapping Population (MNAMP) based on qualitative (chi-square tests of Mendelian gene models) and quantitative (quantitative trait loci (QTL) mapping with 66,685 single nucleotide polymorphic markers) genetic analyses. Four families segregated for resistance to the widely virulent Pgt races of TTKSK, TRTTF, and TTKST. One to five Mendelian genes and five to 19 QTL conferred stem rust resistance in individual families. One family segregated for resistance to Pt race TFBGQ with Lr21 virulence. One Mendelian gene and two QTL controlled resistance to this pathogen race. Three families segregated for resistance to the Pst races PSTv-37 and PSTv-40. Three to five Mendelian genes and two to 12 QTL conferred resistance to these races in individual families. Rust resistant progeny identified from the MNAMP will be useful for enhancing the resistance of wheat to the three rust diseases.
  • Thumbnail Image
    Item
    Hyperspectral image dataset for salt stress phenotyping of wheat
    (2018-04-13) Moghimi, Ali; Yang, Ce; moghi005@umn.edu; Moghimi, Ali; Moghimi, Ali
    The dataset contains hyperspectral images of four wheat lines, each with a control and a salt (NaCl) treatment. Images were captured by a hyperspectral camera (PIKA II, Resonon) under natural light condition one day after salt application when there were no visual symptoms in wheat plants. The camera recorded the spectral response of both control and salt tanks of each line over 240 spectral channels in visible and near infrared region (400 nm to 900 nm) with about 2.1 nm spectral resolution, 640 spatial channels in the cross-track direction, and about 1 mm spatial resolution. Raw images were converted to radiance (Wm−2sr−1nm−1) using a vendor-provided calibration file, and then converted to reflectance (%) using a Spectralon panel. In total 25 spectral bands were disregarded due to high noise. Subsequent to noisy band removal, vegetation pixels were segmented from background using spectral vegetation indices and morphological operation. Although the goal of this study was plant phenotyping to rank salt tolerance of wheat lines, this dataset can be used for other research purposes, such as developing classification algorithms to discriminate healthy and stressed plants and developing methods for spectral feature selection to reduce the dimension of hyperspectral images.
  • Thumbnail Image
    Item
    Identification of new resistance loci to African stem rust race TTKSK in tetraploid wheats based on linkage and genome-wide association mapping
    (Frontiers in Plant Science, 2015-12-09) Laido, Giovanni; Panio, Giosue; Marone, Daniela; Russo, Maria A; Ficco, Donatella B. M.; Giovaniello, Valentina; Cattivelli, Luigi; Steffenson, Brian; De Vita, Pasquale; Mastrangelo, Anna M
    Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn. (Pgt), is one of the most destructive diseases of wheat. Races of the pathogen in the “Ug99 lineage” are of international concern due to their virulence for widely used stem rust resistance genes and their spread throughout Africa. Disease resistant cultivars provide one of the best means for controlling stem rust. To identify quantitative trait loci (QTL) conferring resistance to African stem rust race TTKSK at the seedling stage, we evaluated an association mapping (AM) panel consisting of 230 tetraploid wheat accessions under greenhouse conditions. A high level of phenotypic variation was observed in response to race TTKSK in the AM panel, allowing for genome-wide association mapping of resistance QTL in wild, landrace, and cultivated tetraploid wheats. Thirty-five resistance QTL were identified on all chromosomes, and seventeen are of particular interest as identified by multiple associations. Many of the identified resistance loci were coincident with previously identified rust resistance genes; however, nine on chromosomes 1AL, 2AL, 4AL, 5BL, and 7BS may be novel. To validate AM results, a biparental population of 146 recombinant inbred lines was also considered, which derived from a cross between the resistant cultivar “Cirillo” and susceptible “Neodur.” The stem rust resistance of Cirillo was conferred by a single gene on the distal region of chromosome arm 6AL in an interval map coincident with the resistance gene Sr13, and confirmed one of the resistance loci identified by AM. A search for candidate resistance genes was carried out in the regions where QTL were identified, and many of them corresponded to NBS-LRR genes and protein kinases with LRR domains. The results obtained in the present study are of great interest as a high level of genetic variability for resistance to race TTKSK was described in a germplasm panel comprising most of the tetraploid wheat sub-species.
  • Thumbnail Image
    Item
    Impact of Processing on the Physicochemical and Nutritional Properties of Intermediate Wheatgrass (Thinopyrum intermedium) and Wheat (Triticum sp.)
    (2022-11) Boakye, Prince
    Annual cereal grains are a major part of the human diet. However, their cultivation is less sustainable and is associated with environmental issues such as soil erosion and emission of greenhouse gases into the atmosphere. Cultivating perennial grain crops to supplement these annual grains offers a promising approach to reducing these environmental issues while providing food for the ever-growing human population. To this end, intermediate wheatgrass (IWG), a perennial grain crop, is being developed and explored for mainstream food applications. The first part of this dissertation explored extrusion cooking of IWG for the first time to produce expanded IWG that could be used as snacks and breakfast cereals. First, we optimized the extrusion conditions for the production of expanded IWG. In that work, the effects of extrusion conditions including feed moisture content (20, 24, and 28%), screw speed (200, 300, and 400 rpm), and extrusion temperature (130, 150, and 170 °C) on the physical and functional properties (moisture content, expansion ratio, bulk density, hardness, water absorption index (WAI), water solubility index (WSI)) of IWG were investigated. Response surface methodology (RSM) was used to model and optimize the extrusion conditions to produce expanded IWG. The model coefficient of determination (R2) was high for all the responses (0.87 – 0.98). All the models were found to be significant (p < 0.05) and were validated with independent experiments. Generally, all the extrusion conditions were found to have significant effects on the IWG properties measured. Increasing screw speed and decreasing the extrusion temperature resulted in IWG extrudates with high expansion ratio. This also resulted in IWG extrudates with generally low hardness and bulk density. Screw speed was found to have the most significant effect on water absorption index (WAI) and water solubility index (WSI), with increasing screw speed resulting in a significant (p < 0.05) decrease in WAI and a significant (p < 0.05) increase in WSI. The optimum conditions for obtaining an IWG extrudate with a high expansion ratio and WAI were found to be 20% feed moisture, 200 – 356 rpm screw speed, and 130 – 154 °C extrusion temperature. Then, these optimum conditions were used to produce two expanded IWG products (extrudates I and II), and the physicochemical and nutritional properties of these products were characterized, comparing them to raw IWG flour. We observed that extrusion resulted in slight decreases in dietary fiber, fat, starch, and amylose contents of IWG, whereas protein and ash contents did not change. A significant increase in starch damage after extrusion led to significant increases in starch digestibility and hydration properties of IWG. Correspondingly, slowly digestible starches and resistant starches were significantly reduced after extrusion. Pasting profile studies showed significant decreases in all pasting parameters measured except for breakdown viscosity after extrusion. Higher antioxidant activity and phenolic acid levels, mainly due to ferulic acid, were observed even after extrusion. However, carotenoid content decreased significantly (up to 65.8% reduction in lutein and 50.4% reduction in zeaxanthin). These findings provide useful information on the production of expanded IWG using extrusion cooking. This is critical in the efforts to increase the demand and marketability of IWG. Furthermore, we have shown that extrusion cooking can improve the antioxidant activity and maintain high protein and dietary fiber levels in IWG, but it may not be suitable for preserving carotenoids in IWG.In the second part of this dissertation, we aimed to address an issue with the consumption of wheat, an annual grain that is a major staple worldwide. Wheat provides nearly 20% of calories and protein in the human diet. However, fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) and amylase/trypsin inhibitors (ATIs) present in wheat flour can trigger irritable bowel syndrome (IBS) and non-celiac wheat sensitivity (NCWS) symptoms in some individuals. This has negatively affected the demand and consumption of wheat in recent years. Thus, reducing FODMAPs and ATI concentrations in wheat flour could make the grain accessible to humans with IBS or NCWS. To this end, we first evaluated a diverse panel of heritage and modern spring wheat lines (208 lines in total) grown in two locations in Minnesota (Crookston and Saint Paul) for FODMAPs and ATI levels and carried out a genome-wide association analysis to identify markers associated with wheat FODMAPs and ATIs. The discovery of such markers, in conjunction with a genome-wide selection strategy, could aid in the selection of breeding lines with lower levels of FODMAPs and ATIs. FODMAPs and ATIs were quantified using High-performance anion-exchange chromatography (HPAEC) and High-performance liquid chromatography (HPLC), respectively. A strong population structure was observed, as the first principal component axis alone explained a third of the genotypic variation, and lines clustered into three distinct clusters of einkorn, emmer, and modern wheat lines. Trait correlations (r) were low to moderately high, ranging from 0.06 - 0.54. Broad-sense heritabilities ranged from low to medium (0.18 - 0.55). Association analysis resulted in the detection of 36 quantitative trait loci (QTL) in 15 chromosomes which were distributed in 30 unique genomic regions based on haplotype analysis; five of the 36 QTL were shared among two to four traits. The QTL were of small to medium effect as the range of explained phenotypic variation was 6.4% - 10.5%. There was no overlap among the QTL regions reported in this research compared with those reported in previously published studies. Genomic prediction models predicted the traits with low to moderately strong correlations (r = 0.23 - 0.49). We also investigated the effect of type I sourdough fermentation (4- and 12-h fermentation times) on the FODMAP and ATI levels in twenty-two wheat lines selected from the lines used in the genetics study based on availability and the initial levels of these compounds. We observed that FODMAPs and ATIs were significantly influenced by variety as well as growing location. Longer sourdough fermentation time (12 h) caused up to 69%, 69%, and 41% reductions in fructans, raffinose, and ATIs, respectively, in the resulting sourdoughs. However, a substantial increase in mannitol (550%) was observed after sourdough fermentation. These findings suggest that in type I sourdough fermentation, mannitol production should be monitored, and strategies to reduce its level in the fermented product should be considered.
  • Thumbnail Image
    Item
    Improving the functionality and bioactivity of wheat bran.
    (2012-04) Petrofsky, Keith Eric
    Wheat bran, including the aleurone layer, contains the vast majority of phenolic antioxidants found in the wheat kernel. Unfortunately, about 80% of phenolic acids in wheat bran are structurally bound and insoluble. These bound phenolics are neither bioactive nor bioavailable during digestion. Additionally, wheat bran contains 43% total dietary fiber, but only 3% soluble dietary fiber. Insoluble fiber is less functional than soluble fiber which has been shown to lower cholesterol and regulate blood sugar. We hypothesized that processing could improve the functionality of wheat bran and bioavailability of phytochemicals in the bran. Specifically, we aimed to maximize the physical properties of viscosity and water hydration capacity in wheat bran, while also maximizing the release of bound phenolic antioxidants from the bran. Wheat bran processing included physical treatments of dry grinding, high shear mixing, high pressure homogenization (HPH), and alkali chemical treatments with different concentration, time, and temperature. Sample analysis included particle size, Wheat bran, including the aleurone layer, contains the vast majority of phenolic antioxidants found in the wheat kernel. Unfortunately, about 80% of phenolic acids in wheat bran are structurally bound and insoluble. These bound phenolics are neither bioactive nor bioavailable during digestion. Additionally, wheat bran contains 43% total dietary fiber, but only 3% soluble dietary fiber. Insoluble fiber is less functional than soluble fiber which has been shown to lower cholesterol and regulate blood sugar. We hypothesized that processing could improve the functionality of wheat bran and bioavailability of phytochemicals in the bran. Specifically, we aimed to maximize the physical properties of viscosity and water hydration capacity in wheat bran, while also maximizing the release of bound phenolic antioxidants from the bran. Wheat bran processing included physical treatments of dry grinding, high shear mixing, high pressure homogenization (HPH), and alkali chemical treatments with different concentration, time, and temperature. Sample analysis included particle size, viscosity, water hydration capacity (WHC), water extractable material (Wa-Ex), free phenolics, and visual imaging by scanning electron microscopy (SEM). Prescreening results showed that while HPH helped reduce particle size of bran regardless of treatment, only alkali chemical treatments released the vast majority of bound phenolics. Alkali treatments also contributed to viscosity increase, with interaction of variables of alkali concentration, treatment time, and temperature. Variables for optimization studies included bran grind, alkali concentration, reaction time, and reaction temperature, while process treatments that remained constant were high shear mixing after chemical pretreatment and HPH conditions. Two factorial designs were conducted to optimize viscosity and WHC of bran while maximizing release of bound phenolics. The second factorial design was an augmentation to the first and data was combined for statistical analysis. Viscosity maximum was reached using 0.5mm screen size in bran dry grinding and chemical treatment conditions of 60°C soak temp, 24 hour soak time, 0.1N NaOH concentration. WHC maximum was reached using 0.5mm screen size in bran dry grinding and chemical treatment conditions of 48°C soak temp, 20 hour soak time, 0.7N NaOH concentration. Overall, process optimization was successful and produced wheat bran with a 500% increase in viscosity, 200% increase in WHC, 500% increase in soluble fiber, and a 300 fold increase in free and soluble bound phenolic antioxidants. Visual confirmation by SEM validated analysis results and showed the optimized bran had a very open and porous structure due to the chemical weakening of the alkali treatment and high shear pulverization of the HPH treatment. The optimized viscosity process was scaled up to produce a large quantity of samples for further research in this collaborative study. Work to separate or concentrate the soluble fraction of processed bran utilized centrifugation to produce additional samples of more soluble and more insoluble processed bran fractions.
  • Thumbnail Image
    Item
    Integrating Hyperspectral Imaging and Artificial Intelligence to Develop Automated Frameworks for High-throughput Phenotyping in Wheat
    (2019-02) Moghimi, Ali
    The present dissertation was motivated by the need to apply innovative technologies, automation, and artificial intelligence to agriculture in order to promote crop production while protecting our environment. The main objective of this dissertation was to develop sensor-based, automated frameworks for high-throughput phenotyping of wheat to identify advanced wheat varieties based on three desired traits, including yield potential, tolerance to salt stress (an abiotic stress), and resistance to Fusarium head blight disease (a biotic stress). We leveraged the advantages of hyperspectral imaging, a sophisticated sensing technology, and artificial intelligence including machine learning and deep learning algorithms. Through integrating imaging and high-resolution spectroscopy, hyperspectral imaging provides valuable insights into the internal activity of plants, leaf tissue structure, and physiological changes of plants in response to their environment. Alternatively, advanced machine learning and deep learning algorithms are uniquely suited to extract meaningful features and recognize latent patterns associated with the desired phenotyping trait, and ultimately make accurate inferences and prediction. In the first study (Chapter 2), we focused on salt stress phenotyping of wheat in a hydroponic system. A novel method was proposed for hyperspectral image analysis to assess the salt tolerance of four wheat varieties in a quantitative, interpretable, and don-invasive manner. The results of this study demonstrated the feasibility of quantitative ranking of salt tolerance in wheat varieties only one day after applying the salt treatment. In the second study (Chapter 3), we developed an ensemble feature selection pipeline by integrating six supervised feature selection techniques to identify the most informative spectral bands from high-dimensional hyperspectral images captured for plant phenotyping applications. First, the spectral features were ranked based on their ability to discriminate salt-stressed wheat plants from healthy plants at the earliest stages of stress. The proposed method could drastically reduce the dimension of hyperspectral images from 215 to 15 while improving the accuracy of classifying healthy and stressed vegetation pixels by 8.5%. Second, a clustering algorithm was proposed to form six broad spectral bands around the most prominent spectral features to aid in development of a multispectral camera. In the third study (Chapter 4), we aimed to develop a phenotyping framework for Fusarium head blight (FHB), a devastating disease attacking small grain crops. The most informative spectral bands were identified to detect FHB-infected spikes. The results of this study revealed that a set of two broad spectral bands (766 nm and 696 nm) returns a classification accuracy of 99% in detecting FHB-infected spikes. In the fourth study (Chapter 5), we developed an autonomous robotic framework for high-throughput yield phenotyping of wheat in the field. The data were collected by a hyperspectral camera mounted on an unmanned aerial vehicle flying over three experimental fields containing hundreds of wheat plots during two consecutive growing seasons. A deep neural network was trained to predict the yield of wheat plots and estimate the yield variation at a sub-plot scale. The coefficient of determination for predicting the yield at sub-plot and plot scale were 0.79 and 0.41with normalized root-mean-square error of 0.24 and 0.14, respectively. In the fifth study (Chapter 6), we focused on developing a deep autoencoder network by leveraging a large unlabeled dataset (~ 8 million pixels) to learn an optimal feature representation of hyperspectral images in a low dimensional feature space for yield prediction. The result demonstrated that the trained autoencoder could substantially reduce the dimension of hyperspectral images onto a 3-, 5-, and 10-dimenionsal feature space with a mean squared error less than 7e-5, while retaining the relevant information for yield prediction. At a higher level, this dissertation contributes to improving economic, ecological, and social impacts by improving crop production, reducing pesticides use, and properly leveraging salt-affected farmlands. From an environmental perspective, a cultivar with high yield potential and a cultivar resistant to FHB disease both promote sustainability in crop production and environment by reducing the required fertilizer and pesticide to meet the anticipated farmers’ profit. The intelligent, automated phenotyping frameworks developed in this dissertation can help plant scientists and breeders identify crop varieties with the desired traits tailored around promoting crop production and mitigating food security concerns.
  • Thumbnail Image
    Item
    Losses Associated with Insect Infestation of Farm Stored Shelled Corn and Wheat in Minnesota
    (Minnesota Agricultural Experiment Station, 1981) Barak, Alan V.; Harein, Phillip
  • Thumbnail Image
    Item
    Minnesota no.163 wheat
    (University of Minnesota. Agricultural Experiment Station., 1900) Hays, W.M.; Boss, A.; University of Minnesota, Agricultural Experiment Station
  • Thumbnail Image
    Item
    Molecular diversity, linkage disequilbrium and genetic mapping in East Africa wheat
    (2013-04) Macharia, Godwin Kamau.
    Despite recognition as key bread wheat producers in sub-Saharan Africa, for decades Ethiopia and Kenya have relied on imports to meet local consumption needs. The challenges posed by pests and diseases as exemplified by repeated attacks by the Russian Wheat Aphid, and the new highly virulent race TTKSK (Ug99) of stem rust, have been strong yield barriers. To change this trend, it is important that breeding populations that combine desirable alleles for yield, disease, and pest resistance are developed followed by selection, promotion and adoption of superior cultivars. In the first chapter of this thesis, SNP- based characterization of population structure and diversity in a comprehensive panel of 297, mainly East Africa lines are described. Four to seven subpopulations were identified largely consistent with line breeding era. The oldest East Africa germplasm was found to be most diverse based on several summary statistics. Present day germplasm including that in commercial production was associated with relatively high allelic diversity too. Methods used to detect signatures of past selection successfully identified outlier SNPs possibly under positive selection which could have played an important role in increasing the adaptive range of bread wheat in East Africa. Long range linkage disequilibrium consistent with past observations for this species, was detected and is described in chapter two. Over 50 QTL for adult plant resistance (APR) to stem, leaf and stripe rusts are reported from mixed model association mapping. Similarly, APR previously observed in the cultivar Kenya- Nyangumi was dissected leading to the detection of 15 minor QTL across all rusts. These results are presented in chapter three. In chapter four, results for high and low molecular weight glutenin subunit alleles, puroindoline proteins, grain hardness and other bread making quality-determining traits that were characterized amongst 216 Ethiopia and Kenya bread wheat lines are discussed.
  • Thumbnail Image
    Item
    New resistance in old places: resistance to the Ug99 race group of Puccinia graminis f. sp. tritici in wheat intra/inter-generic hybrids and historic germplasm
    (2015-01) Kielsmeier-Cook, Joshua
    Wheat stem rust caused by the rust fungus, Puccinia graminis f. sp. tritici, threatens global wheat (Triticum aestivum) production. New races originating in Eastern Africa have overcome many existing stem rust resistance genes. The W. J. Sando collection of wheat intra/inter-generic hybrids is a valuable source of stem rust resistance. The entire collection was characterized for seedling stem rust resistance to 8 races of the stem rust pathogen and cytogenetic analysis was performed on select lines. Several accessions are postulated to contain new sources of resistance. Full screening results are displayed in Supplementary Table S1 and the pedigrees of 29 resistant lines are displayed in Supplementary Table S2. South African accession PI 410954 displayed strong resistance to stem rust race TTKSK at the seedling stage and under field conditions. The source of new resistance was located and material suitable for integration into modern spring wheat breeding programs was produced.