Plant Sciences Doctoral Work

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Adaptation of Quality Protein Maize (Zea Mays L.) to Northern U.S. Corn Belt
(North Dakota State University, 2015) Dong, Naiyuan
There is a need to increase the value of crops and develop the next generation of healthier products. Quality protein maize (Zea mays L.) is an option but has never been adapted to short – season environments. Quality protein maize (QPM) with homozygous embryo and endosperm for mutant allele o2 at the α-zeins regulatory gene opaque-2 shows about 60 to 100% increase in lysine and tryptophan essential amino acids when comparing with non-QPM maize. The objectives of this research were to adapt QPM genotypes to the northern U.S. through the NDSU Early QPM Program, and to evaluate the agronomic potential of early generation QPM lines and hybrids developed by the NDSU maize breeding program for the northern USA. Fifty-four inbred lines, including 47 QPM donor lines from the Iowa State University (ISU) maize breeding program, six experimental lines from the NDSU maize breeding program and one ex-PVP line from industry, were selected to produce 94 early-QPM backcross populations. Based on the earliness, protein content, and amino acid levels of lysine, 218 BC1S2 lines were selected for testcrosses with industry testers. Experiments evaluating testcrosses were arranged in 12 x 12 and 10 x 10 partially balanced lattice designs across three environments in 2013 and 2014. Based on this evaluation, totally 48 S2 lines were selected for further development, 17 of them representing the Stiff Stalk (SS) heterotic group and 31 representing the non-SS-group. Selected lines provided unique advanced inbred lines with hybrid combinations showing not only above average grain yield, dry down, and protein content but also, high levels of lysine, tryptophan, and methionine. The results of this research show, for the first time, the successful adaptation of QPM genotypes to short-season environments. The NDSU maize-breeding program has developed the first high quality maize products through the EarlyQPM and EarlyQPMF (for feedstock) national programs.
Advanced Cropping Systems for Oil and Biomass Feedstock Production in the Northern Great Plains
(North Dakota State University, 2015) Zayas, Alfredo Aponte
Video summarizing a Ph.D. dissertation for a non-specialist audience.
Agronomic Practices that Impact Grain Quality Factors of Durum Wheat (Triticum Turgidum L. Var. Durum Desf.)
(North Dakota State University, 2016) Forster, Shana M.
Durum wheat is a type of wheat primarily used for pasta production. North Dakota is the leading producer of durum wheat in the US with average yields of 2700 kg ha-1. Durum wheat price discounts are common and occur due to disease, heavy metal contamination, and environmental issues that impact grain quality. Studies were conducted in order to determine how agronomic approaches might impact durum quality. Experiments were conducted in order to determine what impact planting date, cultivar, and seeding rate had on the agronomic performance and quality of end-use traits. In general, a delay in planting date resulted in a significant decrease in yield and test weight for all cultivars. Cultivars differed for many of the end-use traits evaluated such as protein content, falling number, and vitreous kernel. Seeding rate had little impact on the traits evaluated. No combination of planting date and cultivar was identified that consistently resulted in grain marketed as US Grade 1 hard amber durum (HAD), or ‘choice durum’. Cultivar selection remains the best option for maintaining end-use traits. The effect of Zn fertilizer source and placement on grain Cd were evaluated. Treatments evaluated had no negative impact on grain yield or test weight. The foliar application of 1.1 kg Zn ha-1 Zn-EDTA in combination with 33 kg N ha-1 in the form of UAN applied at Feekes 10 growth stage (boot stage) resulted in the lowest grain Cd, and highest grain Zn, Fe and protein and represents an approach of biofortification for durum wheat.
Agronomic Studies of Forage Brassicas as Full-Season and Cover Crops for Grazing in North Dakota
(North Dakota State University, 2017) Teuber Winkler, Osvaldo Roberto
Annual forages represent a good feed resource to extend the grazing season into fall and winter, providing a good quality forage for the livestock, allowing more efficient use of rangeland, and at the same time improving soil properties. Many species in the Brassicaceae family are used as forages for grazing. Forage brassicas are characterized by high forage yield, with high nutritive value, low establishment and harvest cost (direct grazing), while providing many ecosystems services. Forage brassicas can be grown as full season forage crops or as cover crops planted after a grain crop. The objectives of this study were: 1) to identify brassicas species and cultivars with high biomass production and forage quality when grown as full-season and as cover crops in North Dakota; 2) to determine their optimum sowing date, plant density and the response to different N and S fertilization rates. Replicated experiments were conducted at four sites Fargo, Prosper, Carrington and Walcott, ND in 2012-2014. Results indicate swede (Brassica napus L. var. napobrassica) and kale [B.oleraceae L. convar. acephala (DC)] were the highest forage yielding brassicas when established in full-season and turnip [Brassica rapa L. var. rapa (L.) Thell).], cv. ‘Appin’ was the highest yielding sown after August. In full-season brassicas, delaying sowing date reduced total forage yield in all species but did not influence forage quality. In brassicas sown after August, total forage yield decreased significantly only in radish in the second sowing date. Plant density did not have an effect on forage yield or N accumulation averaged across environments and species in full-season forage brassicas. This was different in brassicas sown after August, where the highest forage yield was obtained with the highest plant density (≥200 plants m-2). Kale and swede leaf, root/stem, and dead matter yield increased up to 200 kg N ha-1 in a linear response. Sulfur and the interaction between N and S did not have an effect in forage yield and quality. Both full-season and cover crops forage brassicas have great potential as supplemental high quality forage for grazing in North Dakota.
Allelic Relationship of A. strigosa Crown Rust Resistance Factors and their Relationship to Pc38 Suppression
(North Dakota State University, 2018) Ardayfio, Naa Korkoi
An investigation of the suppression effect of Pc38 on Pc94 was conducted by developing F2 segregating populations from genotypes possessing Pc38 and Pc94, together with a population void of the Pc38. Segregating phenotypic ratios were used to determine the crown rust resistance suppression at the Pc38 locus. A Leggett/Df-38 F2 population, possessing no Pc38 gene, produced resistant to susceptible ratios of 3:1 and 2:1. Leggett/Dumont and Leggett/Steele population possessing a copy of Pc38 each, produced resistant to susceptible ratios of 1:3, 1:2 and 3:13. Leggett was the resistant parent possessing Pc94 while Dumont and Steele were the susceptible parents possessing Pc38. Df-38, a susceptible parent, contained neither Pc94 nor Pc38. CR91 was used to identify resistant and susceptible plants in the segregating populations. A factor closely linked to Pc38 or the gene itself was confirmed to suppress the resistance effect of Pc94 in this study. A second experiment was conducted to determine the allelic relationship of crown rust resistance genes in 08BT26-2, 08BT70-1, BT1020-1-1 and BT1021-1-1. The genotypes possessed resistance genes introgressed from A. strigosa similar to Leggett. Leggett is homozygous for Pc94. Four different F2 segregating populations were developed from Leggett by 08BT26-2, 08BT70-1, BT1020-1-1 and BT1021-1-1. A crown rust race virulent to Pc94 was used to determine resistant to susceptible ratios of the populations. Crown rust race 16MN (100- 3) was used to discriminate between resistant and susceptible plants. The allelism test confirmed that the resistance gene present in 08BT26-2 and 08BT70-1 genotypes were the same as Pc94 in Leggett while genotypes BT1020-1-1 and BT1021-1-1 were different.
Altering Grapevine Crop-load and Canopy Architecture Through Cultural and Genetic Methods
(North Dakota State University, 2020) Svyantek, Andrej William
North Dakota's extremely short growing season leads to premature harvest of unripe, high acid grapes with atypical fruit chemistry. To combat the short growing season, grape growers utilize labor intensive grapevine canopy management practices to expose grape clusters to sunshine for enhanced ripening potential. This research examined leaf removal and shoot-thinning, two widely utilized canopy management practices, for their effect on fruit chemistry of two regionally important, cold-hardy grapevines, ‘Frontenac’ and ‘Marquette’. These management techniques were effective at altering fruit chemistry as measured by sugar; however, they are costly to employ commercially due to yield reduction and labor requirements. Furthermore, they rarely impacted the targeted fruit component, acidity of grape must. Ultimately, we sought to mitigate labor expenses associated with on-farm canopy management practices by breeding cold-hardy grapevines with reduced single leaf area. To accomplish this goal, we utilized a novel mutant grapevine with highly dissected, technically compound leaves, ‘Chasselas Cioutat’. After crossing ‘Chasselas Cioutat’ with native, North Dakota isolated, wild riverbank grapes (V. riparia) and two interspecific breeding parents (‘Frontenac gris’ and ‘E.S. 5-8-17’), we observed developmental transitions within leaf shape of young seedling grapevines. Newly emerged leaves became progressively more lobed between main veins as seedlings exited juvenility. However, the targeted compound leaf form was not observed in outcrossed progeny, with one rare exception. For these reasons, grapevines were maintained under greenhouse conditions and advanced to the next generation. Within the first generation of inbreeding, segregation was observed for the distinct compound leaf trait. On-going work to isolate quantitative trait loci is merging genetic maps from multiple sequencing technologies with image analysis to create the first high-resolution understanding of genetic control of compound leaf shape in grapevines. Overall, these efforts have provided the foundation for future breeding aimed at incorporating functional leaf shapes (compound leaf morphology) in the vineyard. Future work in North Dakota grapevine management may need to focus on techniques that promote winter survival and early ripening. Future breeding efforts should continue to focus on the use of novel germplasm material to overcome biotic stresses, improve fruit quality, and increase environmental resistance.
Analysis and Identification of QTL for Resistance to Sclerotinia Sclerotiorum in Pea (Pisum sativum L.)
(North Dakota State University, 2018) Ashtari Mahini, Rahil
White mold caused by Sclerotinia sclerotiorumi s one of the most devastating diseases infecting field pea (Pisum sativum L.) which causes severe yield loss worldwide. Population 17 (Lifter/ PI240515), and Population 19 (PI169603/ Medora) were developed by single seed descent and screened by greenhouse evaluation and detached stem assay to identify potential sources of white mold resistance. Twenty-two partial resistant inbred lines were identified with short internode which met at least two resistance criteria based on lesion expansion inhibition (LEI) and nodal transmission inhibition (NTI). To find SNPs (single nucleotide polymorphism) responsible for white mold resistance, Populations 17 and 19 were genotyped using GBS (genotyping by sequencing) methodology and analyzed with the GBS-SNP-CROP pipeline. Linkage maps were constructed for each population and a composite map based on shared SNPs between the two populations was also generated. Nineteen QTL were identified as contributing to resistance to white mold. Seventeen were associated with LEI and two were associated with NTI. The QTL responsible for lesion expansion on LG VII were duplicated in the short internode subset of both populations. Partially resistant inbred lines and QTL responsible for white mold resistance identified in this study can be useful as resources for resistance to S. sclerotiorum in further experiments aimed at developing resistant cultivars.
Association Mapping and Genetic Diversity Studies of Agronomic and Quality Traits in Durum Wheat [Triticum turgidum L. var. durum (Desf.)]
(North Dakota State University, 2017) Johnson, Marina
Genetic diversity studies in breeding programs are important to identify parental lines for hybridization and introgression of desirable alleles into elite germplasm. The genetic diversity analysis of 283 North Dakota State University (NDSU) advanced durum wheat breeding lines developed during the last 20 years indicated that the population was structured according to its breeding history. Total genetic diversity analysis (HT = 0.334) showed adequate level of genetic variation. The results will help in breeding efforts to broaden the genetic base and select lines for crossing as well as for genetic and genomic studies to facilitate the combination of desirable alleles. The quantitative nature of important target traits, combined with environmental effects, makes it difficult to bring the desirable improvement in durum wheat to meet the expectations of all the stakeholders involved in the durum wheat industry. With an objective to identify molecular markers for marker-assisted breeding (MAB), the present study attempted to identify marker-trait associations for six agronomic and 29 quality traits using a genome-wide association study (GWAS) mapping approach. The study used two types of phenotypic datasets, a historic unbalanced dataset belonging to a total of 80 environments collected over a period of 16 years and a balanced dataset collected from two environments, to identify the applicability of historic unbalanced phenotypic data for GWAS analysis. A total of 292 QTL were identified for agronomic and quality traits, with 10 QTL showing major effects (R2 >15%). Over 45% of QTL for agronomic and quality traits were present in both the unbalanced and balanced datasets, with about 50% of those present in both environments in the balanced dataset. Genome-wide association mapping studies identified several candidate markers for use in marker-assisted selection (MAS) for height, gluten strength, distribution of small kernels, polyphenol oxidase (PPO) activity, and yield.
Black Bean Milling and Flour Functionality
(North Dakota State University, 2020) Fernando, Hettige Supun Sandaru
Dry bean utilization by the food industry can be increased by developing value-added processing applications. The goals of this research were to evaluate (1) the effect of milling method on the physical, chemical and functional properties of whole black bean flour and its fractions and (2) the effect of removing soluble phenolic compounds on the functional and rheological properties of black bean protein isolates. Black bean was milled with five laboratory mills [cyclone mill, hammer mill, stone mill (fine, medium, coarse), disc mill (fine, coarse), and centrifugal mill (10,000 or 12,000 rpm and 250, 500, 1000 μm aperture screen)] and the resulting flours were evaluated for their physical, chemical and flow properties of bulk samples and particle size fractions. Whole black bean flour and cotyledon flour were subjected to phenolic extraction and protein isolation, resulting in protein isolates with and without soluble phenolics. Solubility, wettability, dispersibility, water binding capacity, foam capacity and stability, emulsification capacity, and gelation properties of protein isolates were evaluated. Variation in milling method produced flours with significantly different flour characteristics. Geometric mean size of whole bean flour was negatively correlated with starch damage (r = -0.92), L* (r = -0.94), angle of repose (r = -0.94), and angle of slide (r = -0.80 to -0.90) and positively correlated with moisture (r = 0.72), and loose bulk density (r = 0.72). Milling method and particle size interaction was significant on characteristics of black bean flour fractions. Particle circularity of flour fractions had a negative correlation of r = -0.93, r = -0.81, r ≈ -0.95, and r = -0.94 with L*, angle of repose, angle of slide and compact density, respectively. Particle circularity had a positive correlation of r = 0.93 and r = 0.89 with average minimum particle size and loose bulk density, respectively. The removal of soluble phenolic compounds improved the brightness, solubility, wettability, dispersibility, foaming capacity, foaming stability, emulsion capacity, emulsion stability and gelling properties of protein isolates. These findings will help food manufacturers to process black bean ingredients using different mill settings to achieve different functionalities depending on the consumer requirements.
Causes of Dull Brown Color in Durum and Traditional Semolina Pasta
(North Dakota State University, 2019) Cabas Lühmann, Patricia Alejandra
Bleaching of durum wheat (Triticum turgidum L. ssp. durum [Desf.] Husn.) was evaluated by determining the effect of grain moisture content, temperature, and wet/dry cycles with bulk water and with high relative humidity on the hydration of durum wheat grain and their effect on some physical grain quality parameters. Low initial grain moisture, high temperature, and wet/dry cycles increased water gain. Scanning electron microscopy and light microscopy showed that the germ and ventral surface of grain were important for water absorption. A single exposure to moisture (bulk water or high relative humidity) seems to be enough to cause a decline in grain quality. The effect of the environment on pasta color was evaluated by quantifying the relative importance of environment and genotype effects on pasta color and related traits. The relationship between environmental growing conditions, pasta color and semolina quality traits was determined. The environment had the highest relative proportion of variance for pasta color and related traits. Stepwise multiple linear regression indicated that the number of days with RH ≥ 80% diminished pasta color which could be related to increased speck count in semolina, soluble brown pigment content and an increased in semolina redness. The number of days ≤ 13°C enhanced pasta yellowness and pasta color score. However, why the positive effect occurred was not clear. Milling and processing effects on pasta color were evaluated by determining the effect of milling and pasta processing on polyphenol oxidase (PPO) activity, peroxidase (POD) activity, soluble brown pigment content, and yellow pigment content. Milling caused a reduction in yellow pigment content, soluble brown pigment content, PPO activity and POD activity while pasta processing reduced yellow pigment content, and for some genotypes, increased soluble brown pigment content. Stepwise multiple linear regression indicated that yellow pigment content had a positive effect and protein content, semolina ash content, and speck count had a negative effect on pasta color.
Characteristics of Yam Composite Flour: Properties and Function of Bread and Tortilla Making
(North Dakota State University, 2017) Asiyanbi-Hammed, Tawakalit Tope
Consumer interest in dietary fiber is on the rise as more information about its potential impact on health has become available. Flour from yam (Dioscorea rotundata) could have useful applications in the baking industry, in composite flour blends, because of its high level of dietary fiber and other essential nutrients. Study of the chemical composition, physicochemical characteristics, and pasting properties of unfermented-white yam flour (UYF) and fermented-brown yam flour (FYF) were investigated. Studies show that composite flour from yam has high ash, total starch, and fiber content than refined wheat flour. Thermal studies showed the energy required for composite flour gelatinization is greater than that of refined wheat flour. The firmness of FYF gel significantly increased with increasing number of days unlike UYF where slight hardness in texture was observed. This study revealed that each flour type exhibited different characteristics when compared to refined wheat flour. This necessitates further studies to substitute the yam flour samples with refined wheat flour to create composite flours that could be employed in bakery products. Inclusion of UYF and FYF flour at 5, 10, 15 and 20% levels of substitution with wheat flour affect the dough physicochemical, rheological pasting properties, and the nutritional quality. Proximate analysis of the flours carried out shows composite flours were of lower protein value but had higher fiber content than refined wheat flour. Impact on the gluten quality, gassing power, farinograph parameters was observed. The farinograph water absorption increased significantly (p<0.05) for blends prepared with UYF. Investigation revealed that the end-product quality (oven spring, loaf volume, bread crumb, tortilla weight, flexibility, thickness and color) of bread loaves and tortilla was significantly affected. This study demonstrated that incorporation of up to 10% FYF flour appears to give acceptable dough with good viscoelastic properties and bread with quality traits similar to refined wheat bread. This might be because bread itself is a fermented bakery product. For the tortilla; an unfermented product, 20% UYF inclusion seems to be more suitable to produce tortillas with good extensibility, acceptable thickness and whiteness with no dark spots that will appeal to the consumers.
Characterization and Manipulation of the Wheat B Genome
(North Dakota State University, 2017) Zhang, Wei
Common wheat originated from interspecific hybridization of three diploid ancestors followed by spontaneous chromosome doubling. Aegilops speltoides (genome SS) has been controversially considered a possible candidate for the donor of the wheat B genome. However, the relationship of the Ae. speltoides S genome with the wheat B genome remains largely obscure. The first aim of this study was to characterize the homology between the wheat B genome and the Ae. speltoides S genome. In this study, meiotic pairing for each of the B-S homoeologous pairs was investigated individually. Noticeable homology between chromosomes 1B and 1S was discovered, but not between other homoeologous B-S pairs. An Ae. speltoides-originated segment spanning a genomic region of approximately 10.46 Mb was detected on the long arm of wheat chromosome 1B. The Ae. speltoides-originated segment on 1BL was found to co-evolve with the rest of the B genome. Evidently, Ae. speltoides was involved in the origin of the wheat B genome, but should not be considered an exclusive donor of this genome. Aegilops speltoides and Thinopyrum elongatum (genome EE), two of diploid relatives of wheat, are considered important sources of novel genes for wheat improvement. However, the development of compensating wheat-alien translocations has been limited by laborious cytological analysis. This study aimed to develop an effective procedure of inducing, recovering, and detecting homoeologous recombination in wheat-alien gene introgression lines. Totally, 112 wheat-Ae. speltoides 2B-2S and 87 wheat-Th. elongatum 2B-2E translocation lines were developed through this procedure. Composite bin maps for chromosome 2B as well as homoeologous chromosomes 2S and 2E were constructed by genotyping the translocations using 90K SNP arrays. In addition, genes for resistance to stem rust, tan spot, and SNB on chromosome 2S were physically mapped and incorporated into the wheat genome. Also, an Ae. speltoides-derived deleterious growth gene was physically mapped to the subtelomeric region of chromosome 2S. In summary, the results of the study led to a large number of 2B-2S and 2B-2E recombinants, physically mapped disease and growth-related genes on chromosome 2S, developed novel molecular markers, and optimized chromosome engineering procedures.
Characterization of Common Wheat Translocations Carrying Leaf Rust Resistance Genes from Alien Species
(North Dakota State University, 2016) Ibrahim, Mohamed Somo
Leaf rust caused by Puccinia triticina Erikss may inflict significant yield losses in wheat; however, can be controlled by breeding for increased host resistance. In earlier studies, effective, resistance has been transferred to common wheat from the wild relatives Thinopyrum ponticum (Lr19), Aegilops sharonensis (Lr56), Ae. peregrina (Lr59), and Ae. neglecta (Lr62). Each translocation was subsequently re-engineered by the induction of homoeologous chromosome exchanges with a normal wheat chromosome to remove unneeded alien chromatin. For each gene the 3-8 most promising recombinants that retained the least linkage drag, but could not be differentiated, were identified. This study employed physical and genetic mapping in conjunction with molecular markers and genomic in situ hybridization to identify those recombinants that are best suited for breeding. For each gene, the recombinant with the least alien chromatin that also appeared to be fully compensating was identified and marker loci suitable for marker-assisted selection were suggested.
Characterization of Edible Bean Flours: Properties and Functionality
(North Dakota State University, 2013) Simons, Courtney W.
Consumption of pulses is considered part of a healthy diet. Therefore, the opportunity exists for development of new pulse-based ingredients. However, a better understanding of their properties is necessary. The compositional and functional properties will vary depending on the bean type, their physical form (pre-cooked, raw flour, starch or protein fractionates) and growing location. In this study, edible bean flours (pinto, navy, black and small red) were subjected to extrusion cooking to produce snacks and texturized high-protein flour. The extrudates were studied to determine the effect of extrusion on the physical, physicochemical, chemical, sensory, and digestibility properties. Texturized high-protein flour was used in a bread formulation study. Finally, a preliminary study of location effect on production of grassy compounds, e.g. hexanal and hexanol, in pinto beans was conducted to determine importance of growing environment on flavor development during storage. The results of these studies showed that bean flours generally had excellent extrusion properties (good expansion and texture). However, pre-cooked flours had much lower expansion and textural integrity compared to raw bean flours and starch fractionates. Nutritional content (protein, total starch, fiber and ash) of flours were generally retained after extrusion. Lipids and resistant starch (RS) however were significantly reduced. Significant reduction in RS resulted in snacks having high glycemic index. Extrudates had 20% lower raffinose content suggesting reduced potential for flatulence after extrusion processing. Sensory evaluation of pinto, navy and black bean snacks indicated good overall acceptability. Pinto bean high-starch fraction differed in composition and functionality (viscosity and thermal properties) compared to its raw whole flour and extruded form. Adding 5% texturized pinto bean protein to bread increased its lysine content by 50%; without significantly affecting bread quality. A significant statistical interaction between growing location and storage time on hexanol and hexanal concentrations was observed for pinto beans grown in Forest River, Johnstown and Hatton North Dakota. This Dissertation will help processors understand the potential for beans as a food ingredient. Applications may include use in breads and other baked products, extruded puffed snacks, pasta, and soups. Bean flours can improve nutritional quality and provide unique functionality to food systems.
Characterization of Genetic Resistance to Sclerotinia sclerotiorum and Epidemiology of the Disease in Brassica napus L.
(North Dakota State University, 2020) Shahoveisi, Fereshteh
This dissertation contains three research chapters conducted on Sclerotinia stem rot (SSR) of canola (Brassica napus L.). This disease is caused by the fungus Sclerotinia sclerotiorum and is considered endemic in canola-producing areas of North Dakota. The first research chapter presents results of a study that evaluated the role of eight phenotyping scoring systems and nine variant calling and filtering methods in detection of QTL associated with response to SSR. The study, conducted on two doubled-haploid mapping populations, showed that using multiple phenotypic data sets derived from lesion length and plant mortality and imputing missing genotypic data increased the number of QTL detected without negatively affecting the effect (R2) of QTL. Nineteen QTL were detected on chromosomes A02, A07, A09, C01, and C03 in this study. The second research chapter presents results of a work that assessed the role of temperature regimes and wetness duration on S. sclerotiorum ascospore germination and ascosporic infection efficiency. This study showed that optimum ascospore germination occurred at 21 °C while it significantly decreased at 10 and 30 °C. Infection efficacy experiments indicated that extreme temperatures and interrupting wet periods were detrimental for the disease development. A logistic regression model with 75% accuracy was developed for the disease perdition. The third research chapter presents results of a study that evaluated the role of temperature on mycelial growth of 19 S. sclerotiorum isolates collected from different geographical regions and on SSR development on plant introduction (PI) lines with different levels of resistance. Mycelial growth and disease development peaked at 25 °C. While lesion expansion on resistant cultivars and the susceptible check was negatively affected at 30 °C, the disease developed significantly on the PI with a high level of susceptibility. Results of these studies provide insights into integrated management strategies of SSR.
Characterization of Surfactant Quality and Validation of Standard Water Conditioning Testing
(North Dakota State University, 2018) Adams, Jason Wayland
Adjuvants are products added to pesticide applications to increase pest control. There are many different types of adjuvants designed to solve certain problems. Surfactants are a major class of agricultural adjuvant used to increase the efficacy of pesticides. Many companies use physical and chemical characteristics to market surfactants. However, producers do not understand these characteristics. Field efficacy data should be used to effectively market surfactants, but is somewhat limited. The objective of the first study was to evaluate if chemical and physical characteristics of agricultural surfactants can be used to predict field performance. Chemical and physical characteristics tested included HLB, dynamic surface tension, contact angle, and absorption through isolated cuticles. When individual characteristics were used as covariates with field efficacy data, no consistent results were observed. Therefore, physical and chemical characteristics cannot be used to accurately predict field performance of surfactants. In 2011, Zollinger et al. published a paper titled “A test method for evaluating water conditioning adjuvants” as a standardized test method. While this has been an effective test method, a comparison of salt type used has never been conducted. The objective of this research was to validate the standardized test method using three artificially mixed hard water samples with calcium chloride, calcium formate, and calcium nitrate. Field trials were conducted near Hillsboro, ND in 2016 and 2017. Glyphosate and mesotrione were applied at 342 and 70 g ai ha-1, respectively. Three types of water conditioners were evaluated with glyphosate: diammonium sulfate (AMS), AMS replacement, and monocarbamide dihydrogen sulfate (AMADS). Herbicide antagonism was similar between the simulated hard water samples. Within each type of water conditioning adjuvant, antagonism was overcome similarly in all water types. The results of these studies validate the test method established by Zollinger et al. (2011).
Cloning and Characterization of Meiotic Genes Rec8 and Cdc5 and Subcellular Analysis of Kinetochore Orientation in Wheat
(North Dakota State University, 2013) Ma, Guojia
Meiosis is a specialized cell division that halves chromosomes and generates haploid gametes in eukaryotes. It is a dynamic cellular process governed by a complex genetic network. Two key players of this network, Rec8 and Cdc5, were cloned and analyzed using comparative genomics and subcellular immunolocalization methodologies in wheat (Triticum turgidum L., genome AABB). TtRec8 and TtCdc5 were localized to group 1 and 5 chromosomes, with two homoeoalleles in sub-genome A and B, respectively. One of the two TtRec8 homoeoalleles, TtRec8-A1, contains 20 exons in a 6.5 kb-genomic DNA fragment, and the coding region encodes 608 amino acids. Two homoeoalleles of TtCdc5 separately encode 1,081 and 1,084 amino acids. The expression profilings of TtRec8 and TtCdc5 were meiotic tissue dominant in LDN, and the highest levels of TtRec8 and TtCdc5 were at interphase through early prophase I and at pachytene stage of meiosis, separately, and then decreased as meiosis proceeded. TtRec8 protein was detected along the entire chromosomes through the early stages of prophase I. Thereafter, TtRec8 protein was mostly removed from the chromosomes. The DNA sequences and conserved domains of TtRec8 and TtCdc5 as well as their kinetics through the meiotic process in LDN were very similar as the cohesion protein Rec8 and polo-like kinase Cdc5 in models, suggesting their specific roles in meiosis. Chromosome pairing (or synapsis) may play a role in kinetochore orientation during meiosis. Special genotypes that contained both paired (bivalents) and unpaired (univalent) chromosomes in the LDN background were constructed to determine the orientation of sister kinetochores in the univalent and bivalent chromosomes in meiosis I. Among the special genotypes included the hybrids from the crosses of the disomic LDN D-genome substitution lines LDN 1D(1B), LDN 2D(2A), LDN 2D(2B), LDN 3D(3A), LDN 4D(4B), LDN 6D(6A), LDN 6D(6B), LDN 7D(7A), and LDN 7D(7B) with LDN, LDN 1D(1A) with rye (Secale cereale L., genome RR) `Gazelle', LDN with Aegilops tauschii (genome DD) RL5286, and LDN 1D(1B) with Ae. tauschii RL5286. All univalents were found amphitelically orientated and all bivalents syntelically orientated at metaphase I, suggesting meiotic pairing mediates kinetochore orientation and subsequently chromosome segregation in LDN.
Cloning and Characterization of the Iron-Regulated Transporter (IRT) Genes and Their Transcription Factors in Populus
(North Dakota State University, 2015) Huang, Danqiong
Iron deficiency causes chlorosis in many plant species, resulting in yield loss and poor quality. Many tree species including poplar are susceptible to iron deficiency. Trees suffering from iron deficiency often show interveinal chlorotic leaves and in severe cases, branches or an entire tree may die. In this study, two trees of Populus tremula L.‘Erecta’ growing near each other but with contrasting leaf color phenotypes were used to study the causes of chlorosis and the mechanisms of tolerance or susceptibility to iron chlorosis in poplar. A leaf analysis revealed that the iron deficiency tolerant tree (PtG) had a higher level of dry matter content, chlorophyll (a+b), Chl a/b ratio, Zn and Fe content than the iron chlorosis susceptible tree (PtY). A hydroponic culture confirmed the differences in aforementioned physiological parameters between PtG and PtY responding to iron deficiency. Two iron-regulated transporter genes (PtIRT1 and PtIRT3), the native promoter of the PtIRT1 gene (PtIRT1-pro), and two basic helix-loop-helix (bHLH) transcription factors (PtFIT and PtIRO) were cloned and characterized for their responses to iron deficiency in PtG and PtY. Deduced amino acid analysis revealed that PtIRT1, PtIRT3, PtFIT, and PtIRO in PtG were identical to those in PtY. Phylogenetic and putative domain analyses showed that PtIRT1, PtFIT, and PtIRO may function in iron homeostasis, while PtIRT3 may play a role in zinc transport in poplar. The expression of PtIRT1 and PtFIT are root-specific and up-regulated by iron deficiency. The expression of a GUS gene derived by PtIRT1-pro in tobacco was also up-regulated by iron deficiency, but was not root-specific. The expression of PtIRT3 is ubiquitous and up-regulated by iron deficiency, but significantly down-regulated by zinc deficiency. A high correlation in the expression between PtFIT and PtIRT1 was observed in PtG, but not in PtY. Transgenic poplars overexpressing PtIRT1 or PtIRT3 did not have enhanced Fe accumulation; however, an enhanced tolerance to iron deficiency was found in transgenic plants overexpressing PtFIT. The results suggested that the transcription factor PtFIT may be involved in iron deficiency response through regulation of PtIRT1 and PtFIT itself may be regulated by other factors in poplar.
Combining metabolite breeding with good agronomic performance in dry bean (Phaseolus vulgaris L.)
(North Dakota State University, 2024) Rodriguez, Oscar
Growth habit is one of the most important domestication traits in dry bean (Phaseolus vulgaris L.). In the U.S., Type II indeterminate upright varieties have helped farmers to switch from historic two-pass harvest to one-pass in direct harvest. Previous work suggested a stem diameter of 5.6 mm as threshold to select Type II architecture plants suitable for direct combining. In addition, the metabolic profile of indeterminate plants in dry bean is of great interest not only to define differences in seed coat color but to observe relationships with other traits, plant growth one of them. This study aimed to validate the correlation between stem diameter and other agronomic traits using breeding lines from a commercial program; further, this study investigates stem diameter as selection criteria to select genotypes that combine high seed yield and upright architecture, and to find genetic regions related to plant height, stem diameter and metabolic profile using a GWAS. Overall, mean stem diameter values were above 7.5 mm, higher than the proposed threshold of 5.6 mm. Stem diameter, showed no significant GxE interactions and the highest broad-sense heritabilities for pinto and slow darkening pinto. In market classes black, great northern, and navy plant height was the most relevant trait for seed yield variation, while stem diameter had low effect. In contrast, plant height and stem diameter are required to explain part of seed yield variability and continue selecting upright plants for pinto, red/pink, and SD-pinto. According to the GWAS, a region on chromosome Pv07 (40 Mb), was shared between plant height and stem diameter. Genes found in this region relate to plant growth and disease avoidance, which makes this region interesting to continue with further studies for plant architecture. Regarding metabolic studies GWAS identified a very interesting region on chromosome Pv01 (61.4 Mb), related to the enzyme Flavonoid 3'-monooxygenase / Flavonoid 3'-hydroxylase. This enzyme is present in the flavonoid biosynthesis pathway. However, it could also have relationship to plant growth. Further cloning of this region would be ideal to confirm differences in seed coat color and plant growth.
Computational Identification, Phylogenetic and Synteny Analysis of Receptor-Like Kinases “RLK” and Receptor-Like Proteins “RLP” in Legumes
(North Dakota State University, 2018) Restrepo Montoya, Daniel
Legumes are considered the second most important family of crop plants after the grass family based on economic relevance. In recent years, the field of legume genomics has expanded due to advancements in high-throughput sequencing and genotyping technologies. To date, no published comparative genomic analysis explores receptor-like kinases “RLK” and receptor-like proteins “RLP” among legume genomes. Evaluating these RLK and RLP should provide a source of new information because extensive genetic and phenotypic studies have already discovered the diverse roles of RLK and RLP in cell development, disease resistance, and stress responses among other functions. This study demonstrates that a computational logical approach for classifying the RLK/RLP in legumes/non-legumes is statistically well supported and can be used in other plant species. The analysis of RLK/RLP of 7 legumes and 3 non-legume species evaluated suggests that about 2% are RLK and less than 1% of the proteins are RLP. The results suggest a dynamic evolution of RLK and RLP in the legume family. In fact, between 66% to 85% of RLK and 83% to 88% of RLP belong to orthologous clusters among the species evaluated. The remaining RLK and RLP proteins are classified as singletons. The ratio of the pairwise synteny blocks of RLK/RLP among legumes shows a 1:1 relationship. The exception is G. max, which shows an approximately 2:1 ratio due to its recent whole genome duplication (G. max vs. the other six legumes). The other legumes show evidence of a similar proportion of plasma membrane proteins among the legume pairwise synteny blocks.

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