Agricultural Science Commons^™

Mutational Analysis Of The Major Soybean Uref Paralogue Involved In Urease Activation, Joe C. Polacco, D. L. Hyten, Mônica Medeiros-Silva, David A. Sleper, Kristin D. Bilyeu

Department of Agronomy and Horticulture: Faculty Publications

The soybean genome duplicated ~14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO₂ in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting …

Cytokinin-Mediated Source ⁄Sink Modifications Improve Drought Tolerance And Increase Grain Yield In Rice Under Water-Stress, Zvi Peleg, Maria Reguera, Ellen Tumimbang, Harkamal Walia, Eduardo Blumwald

Department of Agronomy and Horticulture: Faculty Publications

Drought is the major environmental factor limiting crop productivity worldwide. We hypothesized that it is possible to enhance drought tolerance by delaying stress-induced senescence through the stress-induced synthesis of cytokinins in crop-plants. We generated transgenic rice (Oryza sativa) plants expressing an isopentenyltransferase (IPT) gene driven by PSARK, a stress- and maturation-induced promoter. Plants were tested for drought tolerance at two yield-sensitive developmental stages: pre- and post-anthesis. Under both treatments, the transgenic rice plants exhibited delayed response to stress with significantly higher grain yield (GY) when compared to wild-type plants. Gene expression analysis revealed a significant shift in expression of hormone-associated …

Evaluation Of Hha And Hha Sepb Mutant Strains Of Escherichia Coli O157:H7 As Bacterins For Reducing E. Coli O157:H7 Shedding In Cattle, Vijay K. Sharma, Evelyn A. Dean-Nystrom, Thomas A. Casey

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

Escherichia coli O157:H7 colonizes cattle intestines by using the locus of enterocyte effacement (LEE)- encoded proteins. The induction of systemic immune response against LEE-encoded proteins, therefore, will prove effective in reducing E. coli O157:H7 colonization in cattle. The previous studies have demonstrated that a hha (encodes for a hemolysin expression modulating protein) deletion enhances expression of LEE-encoded proteins and a sepB (encodes an ATPase required for the secretion of LEE-encoded proteins) deletion results in intracellular accumulation of LEE proteins. In this study, we demonstrate the efficacy of the hha and hha sepB deletion mutants as bacterins for …

The Ability Of Selected Pupal Parasitoids (Hymenoptera: Pteromalidae) To Locate Stable Fly Hosts In A Soiled Equine Bedding Substrate, Jimmy B. Pitzer, Phillip E. Kaufman, Christopher Geden, Jerome A. Hogsette

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

The ability of Spalangia cameroni Perkins, Spalangia endius Walker, and Muscidifurax raptorellus Kogan and Legner to locate and attack stable fly hosts was evaluated under laboratory conditions. Postfeeding third-instar stable fly larvae were released and allowed to pupate in two arena types: large 4.8 liter chambers containing a field-collected, soiled equine bedding substrate; or 120-ml plastic cups containing wood chips. At the time of fly pupariation, parasitoids were released and permitted 72 h to locate and attack hosts. On average, parasitism rates of freely accessible stable fly pupae in cups were not significantly different between parasitoid species. However, parasitism rates …

New Records For The Horse Fly Fauna (Diptera: Tabanidae) Of Jordan With Remarks On Ecology And Zoogeography, Günter Müller, Jerome Hogsette, Edita Revay, Vasiliy Kravchenko, Andrey Leshvanov, Yosef Schlein

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

The horse fly fauna (Diptera: Tabanidae) of Jordan is, after Israel, the richest in the Levant, with 24 known species. During the 20-year project “The Ecology and Zoogeography of the Lepidoptera of the Near East,” we regularly collected blood-feeding flies, resulting in 11 additional species of Tabanidae for Jordan. The new records are: Atylotus quadrifarius (Loew, 1874), Chrysops caecutiens (Linnaeus, 1758), Dasyrhamphis nigritus (Fabricius, 1794), Haematopota pallens Loew, 1871, Nemorius irritans (Ricardo, 1901), Philipomyia graeca (Fabricius, 1794), Tabanus cordiger Meigen, 1820, Tabanus taeniola Palisot de Beauvois, 1806, Tabanus quatuornotatus Meigen, 1820, Tabanus separatus Effllatoun, 1930, and Tabanus spectabilis Loew, 1858. …

Vector Competence Of The Stable Fly (Diptera: Muscidae) For West Nile Virus, Michael S. Doyle, Bethany N. Swope, Jerome A. Hogsette, Kristen L. Burkhalter, Harry M. Savage, Roger S. Nasci

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

In 2006-2007, stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), were suspected of being enzootic vectors of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) during a die-off of American white pelicans (Pelecanus erythrorhynchos Gmelin) (Pelecanidae) in Montana, USA. WNV-positive stable flies were observed feeding en masse on incapacitated, WNV-positive pelicans, arousing suspicions that the flies could have been involved in WNV transmission among pelicans, and perhaps to livestock and humans. We assessed biological transmission by infecting stable flies intrathoracically with WNV and testing them at 2-d intervals over 20 d. Infectious WNV was detected in fly bodies …

Dietary Wheat Germ Oil Influences Gene Expression In Larvae And Eggs Of The Oriental Fruit Fly, Thomas A. Coudron, Chiou Ling Chang, Cynthia L. Goodman, David Stanley

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

Changes in animal nutrition, particularly essential dietary components, alter global gene expression patterns. Our goal is to identify molecular markers that serve as early indicators of the quality of insect culture media. Markers of deficient culture media will increase the efficiency of developing optimal systems for mass rearing beneficial insects and some pest species because decisions on culture media quality can be made without waiting through one or several life cycles. The objective of our current study is to discover molecular markers of essential dietary lipid deficiency in the oriental fruit fly, Bactrocera dorsalis. We reared groups of fruit …

Uncertainty In Modelling Of Faecal Coliform Overland Transport Associated With Manure Application In Maryland, A. K. Guber, Y. A. Pachepsky, A. M. Yakirevich, D. R. Shelton, A. M. Sadeghi, D. C. Goodrich, C. L. Unkrich

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

Concerns for microbial safety of surface water facilitate development of predictive models that estimate concentrations and total numbers of pathogen and indicator organisms leaving manure-fertilized fields in overland flow during runoff events. Spatial variability of bacterial concentrations in applied manure introduces high uncertainty in the model predictions. The objective of this work was to evaluate the uncertainty in model predictions of the manure-borne bacteria overland transport caused by limited information on the spatial distribution of bacteria in surface-applied manure. Experiments were carried out at the ARS Beltsville experimental watershed site (OPE3) in Maryland. Dairy bovine manure was applied at a …

Conservation Reserve Enhancement Program Nebraska Platte-Republican Resources Area

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

Overview

Benefits

Goals

Program Cost

Eligible Areas and Eligibility Requirements

Approved Conservation Practices

Acreage Limitations

Sign-up and Contract Duration

CREP Payments

CREP and CRP

For More Information

Outcrossing And Crossbreeding Recovers Deteriorated Traits In Laboratory Cultured Steinernema Carpocapsae Nematodes, John M. Chaston, Adler R. Dillman, David I. Shapiro-Ilan, Anwar L. Bilgrami, Randy Gaugler, Keith R. Hopper, Byron J. Adams

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

The nematode Steinernema carpocapsae infects and kills many pest insects in agro-ecosystems and is commonly used in biocontrol of these pests. Growth of the nematodes prior to distribution for biocontrol commonly results in deterioration of traits that are essential for nematode persistence in field applications. To better understand the mechanisms underlying trait deterioration of the efficacy of natural parasitism in entomopathogenic nematodes, we explored the maintenance of fitness related traits including reproductive capacity, heat tolerance, virulence to insects and ‘tail standing’ (formerly called nictation) among laboratory-cultured lines derived from natural, randomly mating populations of S. carpocapsae. Laboratory cultured nematode …

Carbon Dioxide Fluxes In Corn–Soybean Rotation In The Midwestern U.S.: Inter- And Intra-Annual Variations, And Biophysical Controls, Guillermo Hernandez-Ramirez, Jerry L. Hatfield, Timothy B. Parkin, Thomas J. Sauer, John H. Prueger

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

Quantifying carbon dioxide (CO₂) fluxes in terrestrial ecosystems is critical for better understanding of global carbon cycling and observed changes in climate. This study examined year-round temporal variations of CO₂ fluxes in two biennial crop rotations during 4 year of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production. We monitored CO₂ fluxes using eddy-covariance (EC) and soil chambers in adjacent production fields near Ames, Iowa. Under the non-limiting soil water availability conditions predominant in these fields, diel and seasonal variations of CO₂ fluxes were mostly controlled by ambient temperature and …

Forage Soybean Yield And Quality Response To Water Use, David C. Nielsen

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

Forages could be used to diversify reduced and no-till dryland cropping systems from the traditional wheat (Triticum aestivum L.)-fallow system in the semiarid central Great Plains. Forages present an attractive alternative to grain and seed crops because of greater water use efficiency and less susceptibility to potentially devastating yield reductions due to severe water stress during critical growth stages. However, farmers need a simple tool to evaluate forage productivity under widely varying precipitation conditions. The objectives of this study were to (1) quantify the relationship between crop water use and dry matter (DM) yield for soybean (Glycine max …

Evaluating Decision Rules For Dryland Rotation Crop Selection, David C. Nielsen, Merle F. Vigil, Joseph G. Benjamin

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

No-till dryland winter wheat (Triticum aestivum L.)-fallow systems in the central Great Plains have more water available for crop production than the traditional conventionally tilled winter wheat-fallow systems because of greater precipitation storage efficiency. That additional water is used most efficiently when a crop is present to transpire the water, and crop yields respond positively to increases in available soil water. The objective of this study was to evaluate yield, water use efficiency (WUE), precipitation use efficiency (PUE), and net returns of cropping systems where crop choice was based on established crop responses to water use while incorporating a …

Towards Estimation Of Canopy Foliar Biomass With Spectral Reflectance Measurements, Lingli Wang, E. Raymond Hunt Jr., John J. Qu, Xianjun Hao, Craig S.T. Daughtry

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

Canopy foliar biomass, defined as the product of leaf dry matter content and leaf area index, is an important measurement for global biogeochemical cycles. This study explores the potential for retrieving foliar biomass in green canopies using a spectral index, the Normalized Dry Matter Index (NDMI). This narrow-band index is based on absorption at the C–H bond stretch overtone and is correlated with leaf dry matter content in fresh green leaves. PROSPECT and SAIL model simulations suggest that the NDMI at the canopy scale is able to minimize the effects of leaf thickness and leaf water content and to maximize …

Development Of Simple Sequence Repeat Markers For Chionanthus Retusus (Oleaceae) And Effective Discrimination Of Closely Related Taxa, R. S. Arias, Timothy A. Rinehart, Richard T. Olsen, Joseph H. Kirkbride Jr., Brian E. Scheffler

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

The genus Chionanthus (Oleaceae Hoffmans. & Link) includes deciduous or evergreen trees and shrubs distributed widely in tropical and sub-tropical areas, including a few temperate species. Although Chionanthus species are planted as ornamental garden plants and commercialized for natural products, genetic information for Chionanthus spp. is lacking. We created micro satellite-enriched libraries of Chionanthus retusus Lindl. & Paxton, assembled 1072 contigs, and detected 1010 repeats. The frequency of the repeats decreased with the increase in repeat length, and the most abundant motifs were: AG, AC, AAG, ACC, AT, and ACTC. We screened 384 markers on 12 accessions of four related …

Identification Of Wild Apple Germplasm (Malus Spp.) Accessions With Resistance To The Postharvest Decay Pathogens Penicillium Expansum And Colletotrichum Acutatum, W. M. Jurick Ii, W. J. Janisiewicz, R. A. Saftner, I. Vico, V. L. Gaskins, E. Park, P. L. Forsline, G. Fazio, W. S. Conway

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

Penicillium expansum and Colletotrichum acutatum cause blue mould and bitter rot of apples during storage which results in significant economic losses. Resistance to these pathogens in commercial apple cultivars has not been documented in the literature. An apple germplasm collection, from the centre of origin in Kazakhstan, is maintained in Geneva, New York. This collection represents a more diverse apple gene pool than commercial cultivars and was evaluated for resistance to the pathogens that cause blue mould and bitter rot. Resistance reactions were skewed towards susceptibility for both fungi and comprised the majority of accessions examined. However, resistance to P. …

Spatial Ramifications Of Crop Selection: Water Quality And Biomass Energy, M. P. Russelle, D. W. Kelley, A. S. Birr, D. C. Tiffany

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

The use of GIS in concert with simple or complex simulation modeling provides an unparalleled way to generate new data and to help a variety of audiences understand spatial patterns of data. From improved understanding, policy incentives can be crafted to reduce adverse environmental impacts of agricultural production at lower costs than would be necessary otherwise. In this chapter, two case studies demonstrate how GIS and modeling can be used to understand how crop selection and soils interact to effect environmental outcomes across an agricultural landscape. We addressed the needs of two distinctly different audiences: (1) a public drinking water …

Nutritional Plane And Selenium Supply During Gestation Affect Yield And Nutrient Composition Of Colostrum And Milk In Primiparous Ewes, A. M. Meyer, J. J. Reed, T. L. Neville, J. F. Thorson, K. R. Maddock-Carlin, J. B. Taylor, L. P. Reynolds, D. A. Redmer, J. S. Luther, C. J. Hammer, K. A. Vonnahme, J. S. Caton

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

The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/ kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed …

Putting The Whole Grain Puzzle Together: Health Benefits Associated With Whole Grains—Summary Of American Society For Nutrition 2010 Satellite Symposium, Satya S. Jonnalagadda, Lisa Harnack, Rui Hai Liu, Nicola Mckeown, Chris Seal, Simin Liu, George C. Fahey

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

The symposium “Putting the Whole Grain Puzzle Together: Health Benefits Associated with Whole Grains” sponsored by the ASN brought together researchers to review the evidence regarding the health benefits associated with whole grains. Current scientific evidence indicates that whole grains play an important role in lowering the risk of chronic diseases, such as coronary heart disease, diabetes, and cancer, and also contribute to body weight management and gastrointestinal health. The essential macro- and micronutrients, along with the phytonutrients present in whole grains, synergistically contribute to their beneficial effects. Current evidence lends credence to the recommendations to incorporate whole grain foods …

Arkansas Cotton Variety Test 2010, Fred M. Bourland, A. B. Beach, D. P. Roberts Jr.

Arkansas Agricultural Experiment Station Research Series

The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant.

Estimation Of Surface Soil Organic Matter Using A Ground-Based Active Sensor And Aerial Imagery, D. F. Roberts, V. I. Adamchuk, J. F. Shanahan, R. B. Ferguson, J. S. Schepers

Department of Agronomy and Horticulture: Faculty Publications

Active canopy sensors are currently being studied as a tool to assess crop N status and direct in-season N applications. The objective of this study was to use a variety of strategies to evaluate the capability of an active sensor and a wide-band aerial image to estimate surface soil organic matter (OM). Grid soil samples, active sensor reflectance and bare soil aerial images were obtained from six fields in central Nebraska before the 2007 and 2008 growing seasons. Six different strategies to predict OM were developed and tested by dividing samples randomly into calibration and validation datasets. Strategies included uniform, …

Soil Fertility And Crop Yields In Long-Term Organic And Conventional Cropping Systems In Eastern Nebraska, Samuel E. Wortman, Tomie D. Galusha, Stephen C. Mason, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Organic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea mays L.) or sorghum (Sorghum bicolor (L.) Moench)–soybean (Glycine max (L.) Merr.)–sorghum or corn–soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghum– sorghum or corn–soybean–winter wheat (wheat, Triticum aestivum L.). The animal manure-based organic system (OAM) …

Stacking Resistance Alleles From Wild And Domestic Soybean Sources Improves Soybean Cyst Nematode Resistance, Myungsik Kim, D. L. Hyten, Terry L. Niblack, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is the most economically important soybean [Glycine max (L.) Merr.] pathogen in the United States. Field SCN populations are adapting to the narrowly based SCN resistance currently deployed in soybean cultivars. The objective of our research was to measure the effects of combinations of SCN resistance genes or quantitative trait loci (QTL) from the wild soybean (Glycine soja Siebold & Zucc.) PI 468916 and the domesticated soybean accessions PI 88788 and PI 437654. Two populations were developed to test the combinations of QTL and genes. Both populations segregated for the …

Moving Micronutrients From The Soil To The Seeds: Genes And Physiological Processes From A Biofortification Perspective, Brian M. Waters, Renuka P. Sankaran

Department of Agronomy and Horticulture: Faculty Publications

The micronutrients iron (Fe), zinc (Zn), and copper (Cu) are essential for plants and the humans and animals that consume plants. Increasing the micronutrient density of staple crops, or biofortification, will greatly improve human nutrition on a global scale. This review discusses the processes and genes needed to translocate micronutrients through the plant to the developing seeds, and potential strategies for developing biofortified crops.

Past And Projected Future Changes In Snowpack And Soil Frost At The Hubbard Brook Experimental Forest, New Hampshire, Usa, John L. Campbell, Scott V. Ollinger, Gerald N. Flerchinger, Haley Wicklein, Katharine Hayhoe, Amey S. Bailey

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

Long-term data from the Hubbard Brook Experimental Forest in New Hampshire show that air temperature has increased by about 1°C over the last half century. The warmer climate has caused significant declines in snow depth, snow water equivalent and snow cover duration. Paradoxically, it has been suggested that warmer air temperatures may result in colder soils and more soil frost, as warming leads to a reduction in snow cover insulating soils during winter. Hubbard Brook has one of the longest records of direct field measurements of soil frost in the United States. Historical records show no long-term trends in maximum …

Molecular Mapping Of Greenbug Resistance Genes Gb2 And Gb6 In T1al.1rs Wheat-Rye Translocations, H. Lu, Jackie C. Rudd, J. D. Burd, Y. Weng

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

Two greenbug resistance genes Gb2 and Gb6 derived from the same donor rye line 'Insave', are present in wheat germplasm lines 'Amigo' and 'GRS1201', respectively as 1AL.1RS wheat-rye translocations. The allelic relationship between the two genes has not been determined, and no molecular markers for Gb6 are available. In this study, molecular mapping of Gb2 and Gb6 was performed in a mapping population derived from a cross between 'N96L9970' (Gb6Gb6) and 'TAM 107' (Gb2Gb2). Segregation among F_2:3 families of host responses to infestation of greenbug biotypes E and KS-1 revealed that Gb2 and Gb6 were …

Relationship Of Cooked-Rice Nutritionally Important Starch Fractions With Other Physicochemical Properties, James Patindol, Harmeet Guraya, Elaine Champagne, Ming-Hsuan Chen, Anna Mcclung

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

Sixteen rice cultivars representing five cytosine-thymine repeat (CT_n) microsatellite genetic marker groups were analyzed for their cooked rice nutritionally important starch fractions (NISFs, which include rapidly digestible (RDS), slowly digestible (SDS), and resistant starch (RS)), basic grain quality indices (apparent amylose (AM), crude protein (CP), alkali spreading value (AS), and gel consistency (GC)), pasting characteristics, and thermal properties. Chemometric tools (bivariate correlation, principal component analysis, multiple linear regression, and partial least squares regression) were used to establish the association of NISF with other milled rice physicochemical properties. CT₁₁ was generally associated with high percentages of RS and …

Regulatory Control Of High Levels Of Carotenoid Accumulation In Potato Tubers, Xiangjun Zhou, Ryan Mcquinn, Zhangjun Fei, Anne-Marie A. Wolters, Joyce Van Eck, Charles Brown, James J. Giovannoni, Li Li

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

Potato (Solanum tuberosum L.) tubers contain a wide range of carotenoid contents. To decipher the key factors controlling carotenoid levels in tubers, four potato lines (Atlantic, Désirée, 91E22 and POR03) were examined by a combination of biochemical, molecular and genomics approaches. These lines contained incremental levels of carotenoids, which were found to be associated with enhanced capacity of carotenoid biosynthesis as evident from norflurazon treatment. Microarray analysis of high and low carotenoid lines (POR03 versus Atlantic) revealed 381 genes that showed significantly differential expression. The carotenoid metabolic pathway genes b-carotene hydroxylase 2 (BCH2) and b-carotene hydroxylase 1 (BCH1), along …

Invited Commentary: Dietary Pattern Analysis, Fumiaki Imamura, Paul F. Jaques

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

The analytic approaches used in nutritional epidemiology for dietary pattern analyses share common characteristics with those of genetic epidemiology. In this issue of the Journal, Gorst-Rasmussen et al. (Am J Epidemiol. 2011;173(10):1097–1104) discuss one such approach. Application of methods used in genetic pattern analyses to nutritional epidemiology could prove valuable but raises important issues that need to be considered because dietary and genetic studies often address different types of questions in analyzing interrelated variables. These different aims require statistical methods that assume different characteristics of the underlying patterns. The authors briefly describe such differences to facilitate interpretation and …

Physiology And Endocrinology Symposium: Role Of The Oviduct In Maintaining Sustained Fertility In Hens, M. R. Bakst

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

In poultry, sperm transferred by natural mating or AI into the distal end of the vagina immediately begin their ascent to the uterovaginal junction (UVJ) at the anterior end of the vagina. However, due to an intense selection process in the vagina, less than 1% of the sperm transferred actually reach the UVJ. Those sperm that do reach the UVJ enter numerous tubular invaginations of the surface epithelium of the vagina located in the UVJ mucosa, collectively referred to as the sperm-storage tubules (SST). Sperm residing in the SST lumen are capable of surviving up to several weeks while retaining …