Agricultural Science Commons^™

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 …

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, …

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.

Switchgrass Contains Two Cinnamyl Alcohol Dehydrogenases Involved In Lignin Formation, Aaron J. Saathoff, Christian M. Tobias, Scott E. Sattler, Eric J. Haas, Paul Twigg, Gautam Sarath

Department of Agronomy and Horticulture: Faculty Publications

Lignin content of switchgrass (Panicum virgatum L.), a bioenergy species, is a critical determinant of biomass quality since it can negatively impact conversion of biomass into liquid fuels via biochemical platforms. Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme in lignin biosynthesis. Here, we have shown that cv. Kanlow switchgrass contains at least two closely related CAD genes (PviCAD1 and PviCAD2) that code for proteins containing highly conserved domains and residues that identify them as bona fide CADs. Both recombinant proteins displayed substrate kinetics consistent with their presumed role in cell wall lignification. Proteomic and immunoblotting detected …

The Composition And Origins Of Genomic Variation Among Individuals Of The Soybean Reference Cultivar Williams 82, William J. Haun, D. L. Hyten, Wayne W. Xu, Daniel J. Gerhardt, Thomas J. Albert, Todd Richmond, Jeffrey A. Jeddeloh, Gaofeng Jia, Nathan M. Springer, Carroll P. Vance, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max) is a self-pollinating species that has relatively low nucleotide polymorphism rates compared with other crop species. Despite the low rate of nucleotide polymorphisms, a wide range of heritable phenotypic variation exists. There is even evidence for heritable phenotypic variation among individuals within some cultivars. Williams 82, the soybean cultivar used to produce the reference genome sequence, was derived from backcrossing a Phytophthora root rot resistance locus from the donor parent Kingwa into the recurrent parent Williams. To explore the genetic basis of intracultivar variation, we investigated the nucleotide, structural, and gene content variation of different …

Genome-Wide Association Analysis Identifies Candidate Genes Associated With Iron Deficiency Chlorosis In Soybean, Sujan Mamidi, Shireen Chikara, R. Jay Goos, D. L. Hyten, Deepti Annam, Samira Mafi Moghaddam, Rian K. Lee, P. B. Cregan, Phillip E. Mcclean

Department of Agronomy and Horticulture: Faculty Publications

Iron deficiency chlorosis (IDC) is a significant yield-limiting problem in several major soybean [Glycine max (L.) Merr.] production regions in the United States. Soybean plants display a variety of symptoms that range from a slight yellowing of the leaf to interveinal chlorosis, to stunted growth that reduces yield. The objective of this analysis was to employ single nucleotide polymorphism (SNP)-based genome-wide association mapping to uncover genomic regions associated with IDC tolerance. Two populations [2005 (n = 143) and 2006 (n = 141)] were evaluated in replicated, multilocation IDC trials. After controlling for population structure and individual relatedness, and selecting …

The Role Of Transition Metal Homeostasis In Plant Seed Development, Elsbeth L. Walker, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Copyright © 2011 Elsevier Ltd. Used by permission.

Moving Magnesium In Plant Cells, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Magnesium (Mg) is among the most abundant mineral elements in plants, yet the knowledge of which genes control its accumulation in specific tissues and organelles lags behind that of many other mineral elements. Only in recent years has identification of important molecular players begun to take shape. In this issue of New Phytologist, Conn et al. (pp. 583–594) shed additional light on two Mg transporters that play important roles in accumulation of Mg in leaf cell vacuoles. Using subcellular-level ion measurements on leaves, gene expression measurements after single-cell sampling, a genetic approach, and clever use of calcium (Ca) and …

Registration Of Seven Winter Wheat Germplasm Lines Carrying The Wsm1 Gene For Wheat Streak Mosaic Virus Resistance, Jasdeep S. Mutti, P. Stephen Baenziger, Robert A. Graybosch, Roy French, Kulvinder S. Gill

Department of Agronomy and Horticulture: Faculty Publications

Seven winter wheat (Triticum aestivum L.) germplasm lines carrying the Wsm1 gene conferring resistance to Wheat streak mosaic virus (WSMV)—Alliance-Wsm1 (Reg. No. GP-858, PI 653710), Arrowsmith-Wsm1 (Reg. No. GP-859, PI 653711), Goodstreak-Wsm1 (Reg. No. GP-860, PI 653712), Harry-Wsm1 (Reg. No. GP-861, PI 653713), Millennium-Wsm1 (Reg. No. GP-862, PI 653714), Wahoo-Wsm1 (Reg. No. GP-863, PI 653715), and Wesley-Wsm1 (Reg. No. GP-864, PI 653716)—were codeveloped by Washington State University, Pullman, WA; the University of Nebraska, Lincoln, NE; and the USDA-ARS. These seven different winter wheat cultivars were selected to provide more sources of effective …

Soybean Diseases : A Pictorial Guide For South Dakota, Lawrence E. Osborne, Darrel Deneke, Thomas Chase, Marie Langham

SDSU Extension Circulars

This publication was assembled to provide growers and crop managers in South Dakota and nearby states with easy-to-use and handy diagnostic information for a number of major or potentially problematic soybean diseases. It is intended to provide a starting point for management decisions.

Following Tetraploidy In Maize, A Short Deletion Mechanism Removed Genes Preferentially From One Of The Two Homeologs, Margaret R. Woodhouse, James C. Schnable, Brent S. Pedersen, Eric Lyons, Damon Lisch, Shabarinath Subramaniam, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Previous work in Arabidopsis showed that after an ancient tetraploidy event, genes were preferentially removed from one of the two homeologs, a process known as fractionation. The mechanism of fractionation is unknown. We sought to determine whether such preferential, or biased, fractionation exists in maize and, if so, whether a specific mechanism could be implicated in this process. We studied the process of fractionation using two recently sequenced grass species: sorghum and maize. The maize lineage has experienced a tetraploidy since its divergence from sorghum approximately 12 million years ago, and fragments of many knocked-out genes retain enough sequence similarity …

Good Agricultural Practices For Food Safety Of Fresh Produce, Laurie Hodges

Department of Agronomy and Horticulture: Faculty Publications

What are the guiding principles of food safety for fresh produce?

• Once contaminated, removing or killing pathogens on produce is very difficult.

• Preventing microbial contamination at all steps, from production to distribution, is strongly favored over treatments to eliminate contamination that may have occurred.

• Document the implementation of prevention programs, and educate workers at all levels of the agricultural and packing environments on food safety.

Key Signatures of a Credible Food Safety Program

The following is a condensed checklist of practices and conditions that reduce the potential for fresh produce to be exposed to pathogenic microbes. Review …

Urban Farm: Naturally Grown Local Food, Stephanie Shepard

Interior Design Program: Terminal Projects

There are many things to be said for the benefits of urban farming. From feeding the hungry, to providing an educational experience for a community that otherwise has no agricultural knowledge, to reducing heat island effect, the gain is almost immeasurable.

According to the United States Census Bureau, 35.9 million people live below the poverty line in America. Requests for emergency food assistance has increased by an average of 14% a year since 2004 and about 20% of those requests generally go unmet. In addition, national food banks report that 23.3 million people turned to their services in 2009, an …

Proceedings Of The 37th Annual Meeting, Southern Soybean Disease Workers (March 10-11, 2010, Pensacola Beach, Florida), Jason Bond, Boyd Padgett, Clayton A. Hollier, Alemu Mengistu, Cliff Coker, Stephen R. Koenning

Southern Soybean Disease Workers: Conference Proceedings

Contents

SSDW treasury report

Southern United States Soybean Disease Loss Estimates for 2009. Compiled by SR Koenning

Green Bean symposium (Jason Bond, moderator)

Factors Contributing to Green Plants at Maturity. DJ Boquet, RL Leonard, GB Padgett, RW Schneider, J Griffin, J Davis, and R Vaverde

The Green Stem Disorder Enigma in Illinois. C Hill and G. Hartman

The Influence of Fungicides, Herbicides, and Their Interactions on Green Bean Syndrome. GB Padgett, DJ Boquet, RW Schneider, and MA Purvis

Association of Stink Bug Injury with A "Green Plant" Malady in Soybean. JH Temple, BR Leonard, J Davis, P Price, and J …

An Inventory And Condition Survey Of The Western Australian Part Of The Nullarbor Region, Peter-Jon A. Waddell, A K. Gardner, P Hennig

Technical Bulletins

The inventory and condition survey of the Western Australian part of the Nullarbor region, undertaken by the Department of Agriculture and Food, Western Australia (DAFWA) between 2005 and 2007, describes and maps the natural resources of the region. This survey report provides a baseline record of the existence and condition of the area's natural resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The Nullarbor region has …

An Integrative Approach To Genomic Introgression Mapping, Andrew J. Severin, Gregory A. Peiffer, Wayne W. Xu, D. L. Hyten, Bruna Bucciarelli, Jamie A. O'Rourke, Yung-Tsi Bolon, David Grant, Andrew Farmer, Gregory D. May, Carroll P. Vance, Randy C. Shoemaker, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Near-isogenic lines (NILs) are valuable genetic resources for many crop species, including soybean (Glycine max). The development of new molecular platforms promises to accelerate the mapping of genetic introgressions in these materials. Here, we compare some existing and emerging methodologies for genetic introgression mapping: single-feature polymorphism analysis, Illumina GoldenGate single nucleotide polymorphism (SNP) genotyping, and de novo SNP discovery via RNA-Seq analysis of next-generation sequence data. We used these methods to map the introgressed regions in an iron-inefficient soybean NIL and found that the three mapping approaches are complementary when utilized in combination. The comparative RNA-Seq approach offers …

Soydb: A Knowledge Database Of Soybean Transcription Factors, Zheng Wang, Marc Libault, Trupti Joshi, Babu Valliyodan, Henry T. Nguyen, Dong Xu, Gary Stacey, Jianlin Cheng

Department of Agronomy and Horticulture: Faculty Publications

Background: Transcription factors play the crucial rule of regulating gene expression and influence almost all biological processes. Systematically identifying and annotating transcription factors can greatly aid further understanding their functions and mechanisms. In this article, we present SoyDB, a user friendly database containing comprehensive knowledge of soybean transcription factors.

Description: The soybean genome was recently sequenced by the Department of Energy-Joint Genome Institute (DOE-JGI) and is publicly available. Mining of this sequence identified 5,671 soybean genes as putative transcription factors. These genes were comprehensively annotated as an aid to the soybean research community. We developed SoyDB - a knowledge database …

Structural And Functional Divergence Of A 1-Mb Duplicated Region In The Soybean (Glycine Max) Genome And Comparison To An Orthologous Region From Phaseolus Vulgaris, Jer-Young Lin, Robert M. Stupar, Christian Hans, D. L. Hyten, Scott A. Jackson

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max) has undergone at least two rounds of polyploidization, resulting in a paleopolyploid genome that is a mosaic of homoeologous regions. To determine the structural and functional impact of these duplications, we sequenced two ~1-Mb homoeologous regions of soybean, Gm8 and Gm15, derived from the most recent ~13 million year duplication event and the orthologous region from common bean (Phaseolus vulgaris), Pv5. We observed inversions leading to major structural variation and a bias between the two chromosome segments as Gm15 experienced more gene movement (gene retention rate of 81% in Gm15 versus 91% in …

Century-Old Mystery Of Puccinia Striiformis Life History Solved With The Identification Of Berberis As An Alternate Host, Yue Jin, Les J. Szabo, Martin Carson

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

The life history of Puccinia striiformis remains a mystery because the alternate host has never been identified. Inoculation of grasses using aeciospores from naturally infected Berberis chinensis and B. koreana resulted in infection on Poa pratensis, producing uredinia typical of stripe rust caused by P. striiformis. Analyses using real-time polymerase chain reaction and DNA sequence confirmed the rust fungus as P. striiformis. Pycnia and aecia were produced on B. chinensis, B. holstii, B. koreana, and B. vulgaris after inoculation using germinating telia of P. striiformis f. sp. tritici. Wheat inoculated with aeciospores from B. chinensis resulted in …

Rna Interference As A Method For Target-Site Screening In The Western Corn Rootworm, Diabrotica Virgifera Virgifera, Analiza P. Alves, Marce D. Lorenzen, Richard W. Beeman, John E. Foster, Blair D. Siegfried

Department of Entomology: Faculty Publications

To test the efficacy of RNA interference (RNAi) as a method for target-site screening in Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) larvae, genes were identified and tested for which clear RNAi phenotypes had been identified in the Coleopteran model, Tribolium castaneum. Here the cloning of the D. v. vergifera orthologs of laccase 2 (DvvLac2) and chitin synthase 2 (DvvCHS2) is reported. Injection of DvvLac2-specific doublestranded RNA resulted in prevention of post-molt cuticular tanning, while injection of DvvCHS2- specific dsRNA reduced chitin levels in midguts. Silencing of both DvvLac2 and DvvCHS2 was confirmed by RT-PCR and quantitative RT-PCR. As in T. …

Spring Seed Guide 2010: Nebraska Variety And Hybrid Tests -- Soybeans, Teshome Regassa, Robert N. Klein, Bruce Anderson, Charles A. Shapiro, Jim Krall

Department of Agronomy and Horticulture: Faculty Publications

NEBRASKA SOYBEAN VARIETY TESTS 2009

Crop Production Summary: The November 2009 estimated soybean yield for Nebraska was 52 bushels per acre from 4.800 million harvested acres. The total production of soybeans for the state was forecasted at 247 million bushels. These estimates are from the November National Agricultural Statistics Service.

Selecting Strawberry Cultivars For Winter Greenhouse Production, Ellen T. Paparozzi, Stacy A. Adams, George E. Meyer, M. Elizabeth Conley, Vicki L. Schlegel, Erin E. Blankenship, Paul E. Read

Department of Agronomy and Horticulture: Faculty Publications

Costs of transportation and food safety concerns have spawned an increase in public support of locally grown vegetables and fruit. With this in mind, a two-phase investigation was planned with the goal of combining low start up costs for sustainable greenhouse production with selection of strawberry cultivars that would provide the greatest number and largest size of berries. Additionally, berries from each cultivar will be analyzed for their beneficial nutraceutical properties to determine if there is a difference among cultivars.

Fine Mapping The Soybean Aphid Resistance Gene Rag1 In Soybean, Ki-Seung Kim, Stephanie Bellendir, Karen A. Hudson, Curtis B. Hill, Glen L. Hartman, D. L. Hyten, Matthew E. Hudson, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

The soybean aphid (Aphis glycines Matsumura) is an important soybean [Glycine max (L.) Merr.] pest in North America. The dominant aphid resistance gene Rag1 was previously mapped from the cultivar ‘Dowling’ to a 12 cM marker interval on soybean chromosome 7 (formerly linkage group M). The development of additional genetic markers mapping closer to Rag1 was needed to accurately position the gene to improve the effectiveness of markerassisted selection (MAS) and to eventually clone it. The objectives of this study were to identify single nucleotide polymorphisms (SNPs) near Rag1 and to position these SNPs relative to Rag1. …

A High Density Integrated Genetic Linkage Map Of Soybean And The Development Of A 1536 Universal Soy Linkage Panel For Quantitative Trait Locus Mapping, D. L. Hyten, Ik-Young Choi, Qijian Song, James E. Specht, Thomas E. Carter Jr., Randy C. Shoemaker, Eun-Young Hwang, Lakshmi K. Matukumalli, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Single nucleotide polymorphisms (SNPs) are the marker of choice for many researchers due to their abundance and the high-throughput methods available for their multiplex analysis. Only recently have SNP markers been available to researchers in soybean [Glycine max (L.) Merr.] with the release of the third version of the consensus genetic linkage map that added 1141 SNP markers to the map. Our objectives were to add 2500 additional SNP markers to the soybean integrated map and select a set of 1536 SNPs to create a universal linkage panel for high-throughput soybean quantitative trait locus (QTL) mapping. The GoldenGate assay …

Crop Registration: The Pathway To Public Access Of Plant Genetic Materials To Build Crops For The Future, D. D. Ellis, K. A. Garland-Campbell, J. A. Grotenhuis, M. M. Jenderek, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Starting in 1926 and continuing for 80+ yr, 11,241 crop genetic materials have been registered as of 31 Dec. 2008. The crop registration process is an important pathway to publically describe and document new and useful genetic materials and to incorporate these into the public domain via the National Plant Germplasm System (NPGS). Crop Registration materials are now searchable via the Germplasm Resources Information Network (GRIN) and demand for registered materials remains strong with more than 9150 registered accessions distributed in the past 26 yr by the NPGS. Guidelines continue to evolve to accommodate global factors effecting germplasm exchange such …

Efficacy Of Singular And Stacked Brown Midrib 6 And 12 In The Modification Of Lignocellulose And Grain Chemistry, Scott E. Sattler, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

In sorghum, brown midrib (bmr) 6 and 12 impair the last two steps of monolignol synthesis. bmr genes were introduced into grain sorghum to improve the digestibility of lignocellulosic tissues for grazing or bioenergy uses following grain harvest. Near-isogenic grain sorghum hybrids (AWheatland X RTx430) were developed containing bmr6, bmr12, and the bmr6 bmr12 double mutant (stacked), and their impacts were assessed in a two-year field study. The bmr genes did not significantly impact grain or lignocellulosic tissue yield. Lignocellulosic tissue from bmr6, bmr12, and stacked hybrids had reduced lignin content and increased in …

Heterosis In Sweet Sorghum And Selection Of A New Sweet Sorghum Hybrid For Use In Syrup Production In Appalachia, T. W. Pfeiffer, M. J. Bitzer, J. J. Toy, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Although heterosis is well established in grain and forage sorghum [Sorghum bicolor (L.) Moench], reports of heterosis in sweet sorghum are limited to results from grain sorghum × sweet sorghum hybrids. Recent development of cytoplasmic male-sterile sweet sorghum lines allows creation of sweet sorghum hybrids for research and industry. Male sterility may also affect allocation of photosynthate to plant parts, creating the potential to increase sugar content in stems by eliminating seed as a sink. The objectives of this study were to compare performance of A₃ cytoplasmic male-sterile lines and A₃ cytoplasmic male-sterile hybrids to fertile B …

Influences Of Wind And Sandblasting On The Endangered Blowout Penstemon, James Stubbendieck, Cheryl D. Dunn, Heidi L. Hillhouse, L. M. Landholt

Department of Agronomy and Horticulture: Faculty Publications

Blowout penstemon Penstemon haydenii is a federally endangered species growing only in areas with active wind erosion in sand dunes of the central United States. This early seral species declines as the blowout habitat stabilizes, allowing later seral species to increase. Blowout penstemon populations and plant size declined in the 1990s when precipitation was higher than normal, resulting in reduced sand movement. We conducted a greenhouse experiment to determine whether blowing sand influenced vigor and persistence of blowout penstemon seedlings. Treatments were wind, sandblasting, wind with sandblasting, and a control. The wind treatment was a constant 14 km h^{–1 …}

Fine Mapping Of The Scn Resistance Locus Rhg1-B From Pi 88788, Myungsik Kim, David L. Hyten, Andrew F. Bent, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is the most economically damaging soybean [Glycine max (L.) Merr.] pest in the USA and genetic resistance is a key component for its control. Although SCN resistance is quantitative, the rhg1 locus on chromosome 18 (formerly known as Linkage Group G) confers a high level of resistance. The objective of this study was to fi ne-map the rhg1-b allele that is derived from plant introduction (PI) 88788. F₂ and F₃ plants and F_3:4 lines from crosses between SCN resistant and susceptible genotypes were tested with genetic markers to …