Agricultural Science Commons^™

Influence Of Environmental Temperature On The Physiological, Endocrine, And Immune Responses In Livestock Exposed To A Provocative Immune Challenge, J.A. Carroll, N.C. Burdick, C. C. Chase Jr, S. W. Coleman, D. E. Spiers

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Although livestock experience many stressors throughout their life, one of the most commonly experienced, and most difficult to control, is stress caused by fluctuations in environmental temperatures that extend beyond the thermoneutral (TN) zone for an animal. In swine, cold stress has long been recognized as a main cause of neonatal morbidity and mortality. A possible explanation for this increased morbidity and mortality may be related to their inability to generate a febrile response. Previously, we reported that the acute phase immune response, including the generation of fever, after exposure to lipopolysaccharide (LPS; Escherichia coli O111: B4; Sigma-Aldrich, St Louis, …

Animal Foraging As A Mechanism For Sediment Movement And Soil Nutrient Development: Evidence From The Semi-Arid Australian Woodlands And The Chihuahuan Desert, David J. Eldridge, Terry B. Koen, Aaron Killgore, Niki Huang, Walter G. Whitford

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

An emerging area of interest in geomorphology over the past two decades has been the effects of biota on ecosystemprocesses.We examinedthe roles of a rangeof vertebrates onsoildisturbance in twomarkedlydifferent environments, the semi-arid woodland of eastern Australia and a Chihuahuan Desert grassland–shrubland in the south-westernUnited States. Foraging pits of soil-disturbingvertebrates variedmarkedly fromsmall scratchings of heteromyid (mainly Dipodomys spp.) rodents (1.8×10⁻⁴m³) to deep (1.0×10⁻² m³) excavations of the burrowing bettong (Bettongia leuseur) and greater bilby (Macrotis lagotis). Vertebratesmoved substantial volumes of soil in both environments, and activity was highly temporally and …

Potential Causes And Consequences Of Decreased Body Size In Field Populations Of Coccinella Novemnotata, John Losey, Jordan Perlman, James Kopco, Samuel Ramsey, Louis Hesler, Edward Evans, Leslie Allee, Rebecca Smyth

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Coccinella novemnotata, the nine-spotted lady beetle, was historically one of the most common lady beetles across the US and southern Canada. In the 1980s it became extremely rare and has remained rare. In 2008 adult C. novemnotata were collected from field populations in Oregon and South Dakota and initial observations suggested that these individuals seemed smaller than the mean size of the species historically. These observations led to a series of experiments to determine if there had been significant decrease in size and if any decrease found was due to a genetic change or to environmental factors. In the …

Transcriptome And Gene Expression Analysis In Cold-Acclimated Guayule (Parthenium Argentatum) Rubber-Producing Tissue, Grisel Ponciano, Colleen M. Mcmahan, Wenshuang Xie, Gerard R. Lazo, Terry A. Coffelt, Jillian Collins-Silva, Aise Nural-Taban, Martin Gollery, David K. Shintani, Maureen C. Whalen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Natural rubber biosynthesis in guayule (Parthenium argentatum Gray) is associated with moderately cold night temperatures. To begin to dissect the molecular events triggered by cold temperatures that govern rubber synthesis induction in guayule, the transcriptome of bark tissue, where rubber is produced, was investigated. A total of 11,748 quality expressed sequence tags (ESTs) were obtained. The vast majority of ESTs encoded proteins that are similar to stress-related proteins, whereas those encoding rubber biosynthesis- related proteins comprised just over one percent of the ESTs. Sequence information derived from the ESTs was used to design primers for quantitative analysis of the …

The Effect Of Row Spacing And Seeding Rate On Biomass Production And Plant Stand Characteristics Of Non-Irrigated Photoperiod-Sensitive Sorghum (Sorghum Bicolor (L.) Moench), John L. Snider, Randy L. Raper, Eric B. Schwab

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

To evaluate row spacing and seeding rate effects on yield and plant stand characteristics of high-biomass sorghum, a photoperiod-sensitive cultivar was sown at three different row spacings (76, 38, and 19 cm) and seeding rates (218,000, 306,000, and 393,000 seeds ha⁻¹ for one site-year and 116,000, 204,000, and 291,000 seeds ha⁻¹ for three site-years) from 2009 to 2010 in Alabama and Arkansas, USA. Measurements included above-ground dry matter production, plant height, stem density, and stem diameter. Narrower row spacing (i.e. 19 cm) produced the highest biomass for all site-years. Increasing seeding rate did not affect yield for three …

A Field Study Of Wind Erosion Following A Grass Fire On The Llano Estacado Of North America, J.E. Stout

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Interactions between earth, wind, and fire have always played an important role in the formation and evolution of the level plains of the Llano Estacado of North America. The uppermost sediments of this vast region are aeolian deposits, formed by aeolian deposition into grassland vegetation. Grass cover enhances aeolian deposition by slowing near-surface winds and vegetation secures sediments once they are deposited. The benefits of grass cover, however, are lost when occasional fires remove protective vegetation fromfields. After a fire, the underlying soil surface becomes exposed and susceptible to wind erosion until the vegetative cover is re-established. The purpose of …

Zebra Chip-Diseased Potato Tubers Are Characterized By Increased Levels Of Host Phenolics, Amino Acids, And Defense-Related Proteins, Christopher M. Wallis, Jianchi Chen, Edwin L. Civerolo

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Little is known about specific host chemistry effects on zebra chip disease symptom development in potatoes (Solanum tuberosum). This research compared chemical profiles and defense-related enzyme levels between non-symptomatic and zebra chip-symptomatic potato tubers. Levels of phenolics, five amino acids, peroxidases, polyphenol oxidases, chitinases, and B-1,3-glucanases were greater in symptomatic tubers than non-symptomatic tubers, and many of these compounds also were positively correlated with zebra chip disease severity. 'Candidatus Liberibacter solanacearum’ was consistently present in symptomatic tubers. However, the lack of associations between titers and tuber chemistry suggests a complicated relationship between this bacterium and zebra chip …

Genomics Of Tropical Fruit Tree Crops, R. S. Arias, James W. Borrone, Cecile L. Tondo, David N. Kuhn, Brian M. Irish, Raymond J. Schnell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The genetic improvement of tropical fruit trees is limited when compared to progress achieved in temperate fruit trees and annual crops. Tropical fruit tree breeding programs require significant resources to develop new cultivars that are adapted to modern shipping and storage requirements. The use of molecular markers in tropical fruit tree breeding is greatly assisting in solving a number of difficult challenges for breeders such as the development of complex family structures for recombination mapping and for recurrent selection. A review of the literature on molecular markers development and new techniques for increasing single-nucleotide polymorphic markers is discussed. The development …

Registration Of ‘Denali’ Wheat, Scott D. Haley, Jerry J. Johnson, Frank B. Peairs, John A. Stromberger, Emily E. Hudson, Scott A. Seifert, Rebecca A. Kottke, Victoria A. Valdez, Jeff B. Rudolph, Terry J. Martin, Guihua Bai, Xianming Chen, Robert L. Bowden, Yue Jin, James A. Kolmer, Ming-Shun Chen, Bradford W. Seabourn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

‘Denali’ (Reg. No. CV-1075, PI 664256) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released cooperatively by Colorado State University (CSU) and Kansas State University (KSU) in August 2011 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at CSU and KSU, USDA-ARS researchers at Manhattan, KS, St. Paul, MN, and Pullman, WA participated in its development. Denali was selected from the cross CO980829/‘TAM 111’ made in 2001 at Fort Collins, CO. CO980829 is an experimental line from CSU with the pedigree ‘Yuma’ (PI 559720)/PI 372129//CO850034/3/4*Yuma/4/NEWS12. …

Reduction Of Mosquito Biting Pressure By Timed-Release 0.3% Aerosolized Geraniol, Edita E. Revay, Amy Junnila, Daniel L. Kline, Rui-De Xue, Ulrich R. Bernier, Vasiliy D. Kravchenko, Zoya Yefremova, Günter Müller

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

We conducted a study to determine the degree of personal protection provided by the Terminix^® ALLCLEAR^® Mosquito Mister – Lantern Edition. This outdoor unit was operated to disperse an aerosolized aqueous 0.3% geraniol emulsion in timed-release intervals of 5.0, 7.5, and 10.0 min. Human volunteers participated in landing catch experiments to test the effect of geraniol sprayed at pre-set time intervals, at two distances: (1) 18 ft (5.49 m), the maximum effective distance claimed by the manufacturer, and (2) 9 ft (2.74 m), half the effective distance from the unit. When aerosolized geraniol was dispensed, reductions in biting …

Natural Product Studies Of U.S. Endangered Plants: Volatile Components Of Lindera Melissifolia (Lauraceae) Repel Mosquitoes And Ticks, Joonseok Oh, John J. Bowling, John F. Carroll, Betul Demirci, K. Hüsnü Can Baser, Theodor D. Leininger, Ulrich R. Bernier, Mark T. Hamann

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The number of endangered plant species in the U.S. is significant, yet studies aimed towards utilizing these plants are limited. Ticks and mosquitoes are vectors of significant pathogenic diseases of humans. Repellents are critical means of personal protection against biting arthropods and disease transmission. The essential oil and solvent extracts from Lindera melissifolia (Walt.) Blume (Lauraceae) (pondberry) drupes were gathered and analyzed by GC and GC–MS. The essential oil obtained from this endangered plant showed a significant dose dependent repellency of ticks and a moderate mosquito repellent effect while the subsequent hexanes extract was completely ineffective. Fractional freezing enriched the …

Genetic Mapping Of Paternal Sorting Of Mitochondria In Cucumber, Claudia I. Calderon, Brian S. Yandell, Michael J. Havey

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Mitochondria are organelles that have their own DNA; serve as the powerhouses of eukaryotic cells; play important roles in stress responses, programmed cell death, and ageing; and in the vast majority of eukaryotes, are maternally transmitted. Strict maternal transmission of mitochondria makes it difficult to select for better-performing mitochondria, or against deleterious mutations in the mitochondrial DNA. Cucumber is a useful plant for organellar genetics because its mitochondria are paternally transmitted and it possesses one of the largest mitochondrial genomes among all eukaryotes. Recombination among repetitive motifs in the cucumber mitochondrial DNA produces rearrangements associated with strongly mosaic (MSC) phenotypes. …

Reproductive Potential Of Stable Flies (Diptera: Muscidae) Fed Cattle, Chicken, Or Horse Blood, Kristina M. Friesen, Gregory D. Johnson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Reproductive potential was assessed for stable fly cohorts fed cattle, chicken, or horse blood. Flies provided chicken blood oviposited20%moreeggs per day than did those fed cattle or horse blood. However, flies provided cattle or horse blood were fecund 50% longer. When both egg viability and number of eggs produced were considered, lifetime reproductive potential was almost twice as high for flies fed cattle or chicken blood than for flies fed horse blood. Maternal investment, which took egg production and volume into account, was higher in cohorts fed cattle blood (70 mm³) when compared with the other treatments (chicken …

Effects Of Pyriproxyfen And Buprofezin On Immature Development And Reproduction In The Stable Fly, S.S. Liu, A.Y. Li, K. H. Lohmeyer, A.A. Perez De Leon

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most significant biting flies that affect cattle. The use of traditional insecticides for stable fly control has only a limited success owing to the insect’s unique feeding behaviours and immature development sites. A laboratory study was conducted to evaluate the effects of two insect growth regulator (IGR) products, pyriproxyfen and buprofezin, on the development of the immature stages of the stable fly and the effects of pyriproxyfen on oviposition and egg hatch. Both pyriproxyfen and buprofezin had significant inhibitory effects on immature development. The LC₅₀s of …

Laboratory Evaluation Of Novaluron As A Development Site Treatment For Controlling Larval Horn Flies, House Flies, And Stable Flies (Diptera: Muscidae), K. H. Lohmeyer, J.M. Pound

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A granular formulation of novaluron (Novaluron 0.2G, 0.2% [AI]), a newer benzoylphenyl urea insecticide, was evaluated for its efficacy in controlling the larval stage of horn flies, Haematobia irritans (L.); house flies, Musca domestica L.; and stable flies, Stomoxys calcitrans (L.), in cow manure. Various rates and insecticide placement locations (top, middle, and bottom of manure) were evaluated in this study and all combinations of these variables reduced adult emergence of all three species when compared with the untreated controls. The presence of deformed pupae indicated that novaluron had an insect growth regulator effect on the developing fly y larvae. …

Soil Carbon Sequestration By Switchgrass And No-Till Maize Grown For Bioenergy, Ronald F. Follett, Kenneth P. Vogel, Gary E. Varvel, Robert B. Mitchell, John Kimble

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Net benefits of bioenergy crops, including maize and perennial grasses such as switchgrass, are a function of several factors including the soil organic carbon (SOC) sequestered by these crops. Life cycle assessments (LCA) for bioenergy crops have been conducted using models in which SOC information is usually from the top 30 to 40 cm. Information on the effects of crop management practices on SOC has been limited so LCA models have largely not included any management practice effects. In the first 9 years of a long-term C sequestration study in eastern Nebraska, USA, switchgrass and maize with best management practices …

Using Sex Pheromone Traps In The Decision-Making Process For Pesticide Application Against Fall Armyworm (Spodoptera Frugiperda [Smith] [Lepidoptera: Noctuidae]) Larvae In Maize, Ivan Cruz, Maria De Lourdes Corrêa Figueiredo, Rafael Braga Da Silva, Ivana Fernandes Da Silva, Cristiane De Souza Paula, John E. Foster

Department of Entomology: Faculty Publications

The fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), is a major pest of maize and frequently demands control measures. The timing of insecticide application is a key factor in determining its efficiency, so an experiment was designed to investigate this. Application of insecticide was based on three criteria: (i) the number of trap-caught moths in a Delta-type trap with a commercial sex pheromone lure placed in the center of the target area, soon after plant emergence; (ii) the percentage of plants exhibiting pinhole-type damage (10% or 20%), and (iii) the percentage of plants exhibiting shot hole–type damage (10% or 20%) …

Susceptibility Of Cry1ab Maize-Resistant And -Susceptible Strains Of Sugarcane Borer (Lepidoptera: Crambidae) To Four Individual Cry Proteins, Liping Zhang, Fangneng Huang, B. Rogers Leonard, Mao Chen, Thomas Clark, Yu Cheng Zhu, David S. Wangila, Fei Yang, Ying Niu

Department of Entomology: Faculty Publications

Sugarcane borer, Diatraea saccharalis (F.), is a major target of Bt maize in South America and many areas of the US mid-south region. Six laboratory strains of D. saccharalis were established from six single-pair F2 families possessing major resistance alleles to Cry1Ab maize hybrids. Susceptibility of the six strains was evaluated on diet treated with each of four purified trypsin-activated Bt proteins, Cry1Ab, Cry1Aa, Cry1Ac, and Cry1F. Bt susceptibility of the six strains was compared with that of known Cry1Ab-susceptible and -resistant strains of D. saccharalis. At least two of the six strains demonstrated a similar level (>526-fold) …

Cover Crop Mixtures For The Western Corn Belt: Opportunities For Increased Productivity And Stability, Samuel E. Wortman, Charles A. Francis, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Achieving agronomic and environmental benefits associated with cover crops oft en depends on reliable establishment of a highly productive cover crop community. The objective of this study was to determine if cover crop mixtures can increase productivity and stability compared to single species cover crops, and to identify those components most active in contributing to or detracting from mixture productivity. A rainfed field experiment was conducted near Mead, Nebraska, United States, in 2010 and 2011. Eight individual cover crop species (in either the Brassicaceae [mustard] or Fabaceae [legume] family) and four mixtures of these species (two, four, six, and eight …

Inheritance Of Grain Polyphenol Oxidase (Ppo) Activity In Multiple Wheat (Triticum Aestivum L.) Genetic Backgrounds, Somrudee Nilthong, Robert A. Graybosch, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Grain polyphenol oxidase (PPO) activity can cause discoloration of wheat (Triticum aestivum L.) food products. Five crosses (PI 117635/Antelope; Fielder/ NW03681; Fielder/Antelope; NW07OR1070/Antelope; NW07OR1066/OR2050272H) were selected to study the genetic inheritance of PPO activity. STS markers, PPO18, PPO29 and STS01, were used to identify lines with putative alleles at the Ppo-A1 and Ppo-D1 loci conditioning low or high PPO activity. ANOVA showed significant genotypic effects on PPO activity (P\0.0001) in all populations. The generations and generation 9 genotype effects were not significant in any population. A putative third (null) genotype at Ppo-A1 (no PCR fragments for PPO18) was discovered …

Identification And Characterization Of Four Missense Mutations In Brown Midrib 12 (Bmr12), The Caffeic O-Methyltranferase (Comt) Of Sorghum, Scott E. Sattler, Nathan A. Palmer, Ana Saballos, Ann M. Greene, Zhanguo Xin, Gautam Sarath, Wilfred Vermerris, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Modifying lignin content and composition are targets to improve bioenergy crops for cellulosic conversion to biofuels. In sorghum and other C4 grasses, the brown midrib mutants have been shown to reduce lignin content and alter its composition. Bmr12 encodes the sorghum caffeic O-methyltransferase, which catalyzes the penultimate step in monolignol biosynthesis. From an EMS-mutagenized TILLING population, four bmr12 mutants were isolated. DNA sequencing identified the four missense mutations in the Bmr12 coding region, which changed evolutionarily conserved amino acids Ala71Val, Pro150Leu, Gly225Asp, and Gly325Ser. The previously characterized bmr12 mutants all contain premature stop codons. These newly identified mutants, along …

Agriculture And Food In Crisis: Conflict, Resistance, And Renewal [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Edited by Fred Magdoff and Brian Tokar. 2010. Monthly Review Press, New York, New York, United States. 348 p. Paperback, cloth US$ 75.00, paper US$ 18.95, ISBN-13 978-1-58367-226-6.

That doubling of food production over the next four decades will be needed to adequately nourish our human population is not news, but the incredible steps essential to achieve that goal and their political and social implications are less well reported. In this series of 16 essays edited by Fred Magdoff and Brian Tokar, several thoughtful specialists in global food issues explore the historical, biological, economic, energy, political and social dimensions of …

Cultivating A Movement: Excerpts From An Oral History Of Organic Farming And Sustainable Agriculture On California’S Central Coast [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Edited by I. Reti and S. Rabkin, 2011. University of California, Santa Cruz, Library, Santa Cruz, California, United States. 299 p., US$19.95, ISBN 9-780972-33431, paper.

Often the most compelling evidence for success of organic farming comes from the personal stories of farmers. Coupled with reports on the application of science in organics, the practical knowledge of people in the field provides a rich foundation for the ongoing growth of this intriguing sector of the food system. This collection of interviews by the staff of the Regional History Project is one unique activity of the University of California, Santa Cruz library, …

Estimating Construction Costs For A Low-Cost Quonset-Style Greenhouse, David P. Lambe, Stacy A. Adams, Ellen T. Paparozzi

Department of Agronomy and Horticulture: Faculty Publications

Double polyethylene Quonset-style greenhouses offergrowers and farmers a more cost-effective structure than glass- or acrylic-covered structures for growing plants off-season. These greenhouses are especially applicablefor producing off-season high value crops such as fruits and vegetables for local markets. To support this production alternative, this publication contains a list of greenhouse components, the start-up costs associated with these items and an estimate of the number of person hours required to assemble and outfit a 24-foot-by-72-foot double polyethylene, air-inflated greenhouse structure. As there are many options available for building double polyethylene greenhouses, the main purpose of this publication is to identify the …

The ‘Pi 438489b’ By ‘Hamilton’ Snp-Based Genetic Linkage Map Of Soybean [Glycine Max (L.) Merr.] Identified Quantitative Trait Loci That Underlie Seedling Sds Resistance, Kassem My Abdelmajid, Laura Ramos, Leonor Leandro, Gladys Mbofung, D. L. Hyten, Stella K. Kantartzi, Robert L. Grier Iv, Victor N. Njiti, Khalid Meksem

Department of Agronomy and Horticulture: Faculty Publications

Soybeans [Glycine max (L.) Merr.] are susceptible to many diseases including fungal diseases such as soybean sudden death syndrome (SDS). Several studies reported SDS resistance quantitative trait loci (QTL) on the soybean genome using different recombinant inbred line (RIL) populations and low density genetic linkage maps. High density exclusively single nucleotide polymorphisms-based (SNP-based) maps were not yet reported in soybean. The objectives of this study were (1) to construct a high density SNP-based genetic linkage map of soybean using the ‘PI438489B’ by ‘Hamilton’ (PIxH, n=50) recombinant inbred line population, and (2) to map QTL for SDS resistance using this …

Structural Variants In The Soybean Genome Localize To Clusters Of Biotic Stress-Response Genes, Leah K. Mchale, William J. Haun, Wayne W. Xu, Pudota B. Bhaskar, Justin E. Anderson, D. L. Hyten, Daniel J. Gerhardt, Jeffrey A. Jeddeloh, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Genome-wide structural and gene content variations are hypothesized to drive important phenotypic variation within a species. Structural and gene content variations were assessed among four soybean (Glycine max) genotypes using array hybridization and targeted resequencing. Many chromosomes exhibited relatively low rates of structural variation (SV) among genotypes. However, several regions exhibited both copy number and presence-absence variation, the most prominent found on chromosomes 3, 6, 7, 16, and 18. Interestingly, the regions most enriched for SV were specifically localized to gene-rich regions that harbor clustered multigene families. The most abundant classes of gene families associated with these regions …

Identification Of Positive Yield Qtl Alleles From Exotic Soybean Germplasm In Two Backcross Populations, K.-S. Kim, B. W. Diers, D. L. Hyten, M. A. Rouf Mian, J. G. Shannon, R. L. Nelson

Department of Agronomy and Horticulture: Faculty Publications

Increasing seed yield is an important breeding goal of soybean [Glycine max (L.) Merr.] improvement efforts. Due to the small number of ancestors and subsequent breeding and selection, the genetic base of current soybean cultivars in North America is narrow. The objective of this study was to map quantitative trait loci (QTL) in two backcross populations developed using soybean plant introductions as donor parents. The first population included 116 BC₂F₃-derived lines developed using ‘‘Elgin’’ as the recurrent parent and PI 436684 as the donor parent (E population). The second population included 93 BC₃F …

Molecular Mapping Of Soybean Rust Resistance In Soybean Accession Pi 561356 And Snp Haplotype Analysis Of The Rpp1 Region In Diverse Germplasm, Ki-Seung Kim, Jair R. Unfried, D. L. Hyten, Reid D. Frederick, Glen L. Hartman, Randall L. Nelson, Qijian Song, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

Soybean rust (SBR), caused by Phakopsora pachyrhizi Sydow, is one of the most economically important and destructive diseases of soybean [Glycine max (L.) Merr.] and the discovery of novel SBR resistance genes is needed because of virulence diversity in the pathogen. The objectives of this research were to map SBR resistance in plant introduction (PI) 561356 and to identify single nucleotide polymorphism (SNP) haplotypes within the region on soybean chromosome 18 where the SBR resistance gene Rpp1 maps. One-hundred F_2:3 lines derived from a cross between PI 561356 and the susceptible experimental line LD02-4485 were genotyped with genetic …

Advances In Genome Sequencing And Genotyping Technology For Soybean Diversity Analysis, David L. Hyten

Department of Agronomy and Horticulture: Faculty Publications

The completion of a soybean draft whole genome sequence along with advances in sequencing and genotyping technologies are creating a revolution in soybean genomics. The draft whole genome sequence of soybean is allowing researchers to fully take advantage of this new technology and is rapidly changing how soybean germ plasm is mined. Genetic markers such as SNPs can be quickly identified by using next generation sequencing and assayed on a large number of materials using advanced technologies that can genotype tens of thousands of markers on thousands of individuals very rapidly. This ability to qUickly identify and genotype genetic diversity …

High-Resolution Mapping Of Open Chromatin In The Rice Genome, Wenli Zhang, Yufeng Wu, James C. Schnable, Zixian Zeng, Michael Freeling, Gregory E. Crawford, Jiming Jiang

Department of Agronomy and Horticulture: Faculty Publications

Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We generated genome-wide high-resolution maps of DNase I hypersensitive (DH) sites from both seedling and callus tissues of rice (Oryza sativa). Approximately 25% of the DH sites from both tissues were found in putative promoters, indicating that the vast majority of the gene regulatory elements in rice are not located in promoter regions. We found 58% more DH sites in …