Life Sciences Commons^™

Increased Abundance Of Arbuscular Mycorrhizal Fungi In Soil Coincides With The Reproductive Stages Of Maize, M. Susana Grigera, Rhae A. Drijber, Brian J. Wienhold

Department of Agronomy and Horticulture: Faculty Publications

Arbuscular mycorrhizal (AM) fungi are recognized for their positive effects on plant growth, playing an important role in plant P nutrition. We used C16:1cis11 and C18:1cis11 fatty acid methyl ester (FAME) biomarkers to monitor the dynamics of AM fungi during the reproductive stages of maize (Zea mays L.) grown at high yield in Nebraska, USA. Two fields with four different levels of P availability were sampled throughout the reproductive stages. Chambers, made of PVC enclosed mesh fabric to allow passage of roots and hyphae(+R) or hyphae alone (-R) and amended with either KH₂PO …

Distribution Of The Arbuscular Mycorrhizal Biomarker C16:1Cis11 Among Neutral, Glyco And Phospholipids Extracted From Soil During The Reproductive Growth Of Corn, Maria S. Grigera, Rhae A. Drijber, Rebecca A. Shores-Morrow, Brian J. Wienhold

Department of Agronomy and Horticulture: Faculty Publications

Arbuscular mycorrhiza (AM) fungi form symbiotic relationships with the majority of land plants and are known for their positive effects on plant P acquisition and soil quality. The extramatrical growth of the mycelium is a key factor in nutrient acquisition by the symbiont. Soil grinding and extraction/fractionation of lipids were used in a field experiment to identify probable sources of the AM biomarker C16:1cis11 and its functional significance during reproductive growth of corn (Zea mays L.). Chambers, enclosed with a 1mm mesh fabric to allow roots and hyphae to pass into the enclosed soil volume, were installed …

Understanding And Modeling The Effect Of Temperature And Daylength On Soybean Phenology Under High-Yield Conditions, T. D. Setiyono, Albert Weiss, James E. Specht, A. M. Bastidas, Kenneth G. Cassman, A. Dobermann

Department of Agronomy and Horticulture: Faculty Publications

Temperature and photoperiod can be used to simulate soybean (Glycine max [L.] Merr) phenology because they serve as surrogates for complex biochemical pathways leading to the appearance of certain developmental stages at the whole plant level. We developed a soybean phenology model (SOYDEV) which utilizes non-linear temperature and photoperiod functions and separates floral induction and post-induction for simulating time of flowering. This model accurately simulated the dynamics of vegetative development, final node number and the occurrence of major reproductive stages such as flowering (R₁), beginning pod (R₃), mid-pod elongation (R_3,5), beginning seed (R …

Fertility Restoration Of The Sorghum A3 Male-Sterile Cytoplasm Through A Sporophytic Mechanism Derived From Sudangrass, Hoang V. Tang, Jeffrey F. Pedersen, Christine D. Chase, Daryl R. Pring

Department of Agronomy and Horticulture: Faculty Publications

Fertility restoration of sorghum [Sorghum bicolor (L.) Moench] lines carrying the IS1112C (A3 group) male-sterile cytoplasm has been documented as a two-gene gametophytic mechanism involving complementary action of restoring alleles designated Rf3 and Rf4, as derived from IS1112C. Fertility restoration capability has also been reported from sudangrass (S. bicolor subsp. drummondii) populations. We describe characteristics of a fertility restoration system derived from sudangrass, in which male-sterile individuals were observed at high frequency in backcross and F₂-F₃ segregating populations. Segregation analyses were consistent with a sporophytic restoration system involving two complementary genes. Pollen iodine …

Nutrient Use Efficiency: Measurement And Management, Achim Dobermann

Department of Agronomy and Horticulture: Faculty Publications

Mineral fertilizers have sustained world agriculture and thus global population and wealth growth for more than 100 years (Smil, 2001; Stewart et al., 2005). Their contribution to increasing crop yields has spared millions of hectares of natural ecosystems that otherwise would have been converted to agriculture (Balmford et al., 2005). However, lacking, imbalanced, inappropriate or excessive use of nutrients in agricultural systems remains a concern. Nutrient mining is a major cause for low crop yields in parts of the developing world, particularly Africa. In other situations, nutrients such as nitrogen (N) and phosphorus (P) often move beyond the bounds of …

Map Location Of The Rpp1 Locus That Confers Resistance To Soybean Rust In Soybean, D. L. Hyten, G. L. Hartman, R. L. Nelson, R. D. Frederick, V. C. Concibido, J. M. Narvel, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean rust (SBR), caused by Phakopsora pachyrhizi, was first discovered in North America in 2004 and has the potential to become a major soybean [Glycine max (L.) Merr.] disease in the USA. Currently, four SBR resistance genes have been identifi ed but not mapped on the soybean genetic linkage map. One of these resistance genes is the Rpp1 gene, which is present in the soybean accession PI 200492. The availability of molecular markers associated with Rpp1 will permit marker-assisted selection and expedite the incorporation of this gene into U.S. cultivars. We compared simple sequence repeat (SSR) markers between …

A Soybean Transcript Map: Gene Distribution, Haplotype And Single-Nucleotide Polymorphism Analysis, Ik-Young Choi, D. L. Hyten, Lakshmi K. Matukumalli, Qijian Song, Julian M. Chaky, Charles V. Quigley, Kevin Chase, K. Gordon Lark, Robert S. Reiter, Mun-Sup Yoon, Eun-Young Hwang, Seung-In Yi, Nevin D. Young, Randy C. Shoemaker, Curtis P. Van Tassell, James E. Specht, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

The first genetic transcript map of the soybean genome was created by mapping one SNP in each of 1141 genes in one or more of three recombinant inbred line mapping populations, thus providing a picture of the distribution of genic sequences across the mapped portion of the genome. Singlenucleotide polymorphisms (SNPs) were discovered via the resequencing of sequence-tagged sites (STSs) developed from expressed sequence tag (EST) sequence. From an initial set of 9459 polymerase chain reaction primer sets designed to a diverse set of genes, 4240 STSs were amplified and sequenced in each of six diverse soybean genotypes. In the …

Barcsoysnp23: A Panel Of 23 Selected Snps For Soybean Cultivar Identification, M. S. Yoon, Q.J. Song, I. Y. Choi, James E. Specht, D. L. Hyten, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

This report describes a set of 23 informative SNPs (BARCSoySNP23) distributed on 19 of the 20 soybean linkage groups that can be used for soybean cultivar identification. Selection of the SNPs to include in this set was made based upon the information provided by each SNP for distinguishing a diverse set of soybean genotypes as well as the linkage map position of each SNP. The genotypes included the ancestors of North American cultivars, modern North American cultivars and a group of Korean cultivars. The procedure used to identify this subset of highly informative SNP markers resulted in a significant increase …

Highly Variable Patterns Of Linkage Disequilibrium In Multiple Soybean Populations, D. L. Hyten, Ik-Young Choi, Qijian Song, Randy C. Shoemaker, Randall L. Nelson, Jose M. Costa, James E. Specht, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Prospects for utilizing whole-genome association analysis in autogamous plant populations appear promising due to the reported high levels of linkage disequilibrium (LD). To determine the optimal strategies for implementing association analysis in soybean (Glycine max L. Merr.), we analyzed the structure of LD in three regions of the genome varying in length from 336 to 574 kb. This analysis was conducted in four distinct groups of soybean germplasm: 26 accessions of the wild ancestor of soybean (Glycine soja Seib. et Zucc.); 52 Asian G. max Landraces, the immediate results of domestication from G. soja; 17 Asian Landrace …

Grassland Composition Affects Season Shifts In Seed Preference By Pogonomyrmex Barbatus (Hymenoptera: Myrmicinae) In The Edwards Plateau, Texas, Nancy Nicolai, Jerry L. Cook, Fred E. Smeins

Department of Agronomy and Horticulture: Faculty Publications

The effects of season and community composition as generated by livestock herbivory of differing intensity on seed species preference by Pogonomyrmex barbatus (F. Smith) were studied in a semiarid savanna on the Edward’s Plateau, TX. Seasonal differences in nutrient requirements of the colony could lead to differential preferences for seeds harvested in spring and fall. Field cafeteria studies were conducted to test the hypothesis that late successional species, with their high nutrient content, would be chosen regardless of grazing intensity or season. Commercial seeds of known nutrient content were used to test the hypothesis that high protein levels would be …

The End Of Poverty: Economic Possibilities For Our Time [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

In what is likely to be a highly controversial book in global economic circles, macro-economist Jeffrey Sachs provides a critical analysis of current failed development aid policies of the World Bank and the International Monetary Fund in the eastern block and the Third World. Based on extensive travel, consulting with governments, and practical experience with both successes and failures, the author provides convincing evidence that a major shift in assistance policy is needed to alleviate poverty in our time. Yet contrary to many who see the challenges in Asia and especially Africa as impossible to solve, Sachs provides an impressive …

Corn–Velvetleaf (Abutilon Theophrasti ) Interference Is Affected By Sublethal Doses Of Postemergence Herbicides, Brescia R. M. Terra, Alexander R. Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Injury to weeds from sublethal doses of POST herbicides may reduce the effect of weed interference on crop yield. Information on how herbicide dose influences weed mortality, growth, and seed production is needed to assess the potential benefit of applying reduced herbicide doses. Field experiments were conducted at Mead, NE, in 2001 and 2002 to quantify velvetleaf mortality, growth, and corn–velvetleaf interference in response to varying doses of three POST herbicides. Untreated velvetleaf at six densities (0, 1, 3, 6, 12, and 20 plants m^-1 corn row) was grown in mixture with corn to establish a baseline corn–velvetleaf interference …

Comparative Nitrogen Uptake And Distribution In Corn And Velvetleaf (Abutilon Theophrasti), John L. Lindquist, Darren C. Barker, Stevan Z. Knezevic, Alexander R. Martin, Daniel T. Walters

Department of Agronomy and Horticulture: Faculty Publications

Weeds compete with crops for light, soil water, and nutrients. Nitrogen (N) is the primary limiting soil nutrient. Forecasting the effects of N on growth, development, and interplant competition requires accurate prediction of N uptake and distribution within plants. Field studies were conducted in 1999 and 2000 to determine the effects of variable N addition on monoculture corn and velvetleaf N uptake, the relationship between plant N concentration ([N]) and total biomass, the fraction of N partitioned to leaves, and predicted N uptake and leaf N content. Cumulative N uptake of both species was generally greater in 2000 than in …

The Ripple Effect: Biofuels, Food Security, And The Environment, Rosamond L. Naylor, Adam Liska, Marshall B. Burke, Walter P. Falcon, Joanne C. Gaskell, Scott D. Rozelle, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

The integration of the agricultural and energy sectors caused by rapid growth in the biofuels market signals a new era in food policy and sustainable development. For the first time in decades, agricultural commodity markets could experience a sustained increase in prices, breaking the long-term price decline that has benefited food consumers worldwide. Whether this transition occurs—and how it will affect global hunger and poverty—remain to be seen. Will food markets begin to track the volatile energy market in terms of price and availability? Will changes in agricultural commodity markets benefit net food producers and raise farm incomes in poor …

Simulation Study Of The Competitive Ability Of Erect, Semi-Erect, And Prostrate Cowpea (Vigna Unguiculata) Genotypes, G. Wang, M. E. Mcgiffen Jr., John L. Lindquist, J. D. Ehlers, I. Sartorato

Department of Agronomy and Horticulture: Faculty Publications

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics, and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterized, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the …

Influence Of Planting Date And Weed Interference On Sweet Corn Growth And Development, Martin M. Williams Ii, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, IL, to quantify the influence of planting date and weed interference on growth of sweet corn height, leaf area, aboveground biomass, and phenological development. Crop growth response to weed interference (presence or absence) was determined for sweet corn planted early May (EARLY) and late June (LATE). Dominant weed species included barnyardgrass [Echinochloa crus-galli (L.) Beauv.], common lambsquarters (Chenopodium album …

Ethylene Involvement In The Regulation Of The H+-Atpase Csha1 Gene And Of The New Isolated Ferric Reductase Csfro1 And Iron Transporter Csirt1 Genes In Cucumber Plants, Brian M. Waters, Carlos Lucena, Francisco J. Romera, Gena G. Jester, April N. Wynn, Carmen L. Rojas, Esteban Alcántara, Rafael Pérez-Vicente

Department of Agronomy and Horticulture: Faculty Publications

In previous works using ethylene inhibitors and precursors, it has been shown that ethylene participates in the regulation of several Fe-deficiency stress responses by Strategy I plants, such as enhanced ferric reductase activity, rhizosphere acidification, and subapical root hair development. Furthermore, recent evidence suggests that ethylene could regulate the expression of both the ferric reductase and the iron transporter genes of Strategy I plants by affecting the FER (or FER-like) transcription factor. Recently, two H⁺-ATPase genes have been isolated from cucumber roots, CsHA1 and CsHA2. CsHA1 is up-regulated under Fe deficiency while CsHA2 is constitutively expressed. In …

Fertility Restoration Of The Sorghum A3 Male-Sterile Cytoplasm Through A Sporophytic Mechanism Derived From Sudangrass, Hoang V. Tang, Jeffrey F. Pedersen, Christine D. Chase, Daryl R. Pring

Department of Agronomy and Horticulture: Faculty Publications

Fertility restoration of sorghum [Sorghum bicolor (L.) Moench] lines carrying the IS1112C (A3 group) male-sterile cytoplasm has been documented as a two-gene gametophytic mechanism involving complementary action of restoring alleles designated Rf3 and Rf4, as derived from IS1112C. Fertility restoration capability has also been reported from sudangrass (S. bicolor subsp. drummondii) populations. We describe characteristics of a fertility restoration system derived from sudangrass, in which male-sterile individuals were observed at high frequency in backcross and F2-F3 segregating populations. Segregation analyses were consistent with a sporophytic restoration system involving two complementary genes. Pollen iodine staining in fertile …

World Agriculture And Environment: A Commodity-By-Commodity Guide To Impacts And Practices [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

This comprehensive reference book provides a good overview of global agriculture at the end of the millennium. In the introduction, author Jason Clay brings his long experience—in farming, teaching, and government service—into the presentation of a balanced perspective on how production must be balanced with concern for the environment. Now with World Wildlife Fund, he couples a background in economics, anthropology and geography with considerable professional experience in aquaculture and cooperation in the private sector to explore multiple aspects of agriculture and food production. He is particularly effective in discussing the economic and environmental sustainability of the food system, although …

Evaluating Bispyribac-Sodium And Sulfosulfuron For Control Of Roughstalk Bluegrass, Debbie Morton, Daniel Weisenberger, Zachary Reicher, Bruce Branham, Bill Sharp, Roch E. Gaussoin, John Stier, Eric Koeritz

Department of Agronomy and Horticulture: Faculty Publications

Roughstalk bluegrass (Poa trivialis L.) is a troublesome weed on golf courses, home lawns, and athletic fields from the Midwest to the mid-Atlantic states. Bispyribacsodium and sulfosulfuron have recently been labeled for roughstalk bluegrass control, but their use needs to be refined. Our objective was to determine the most effective herbicide strategies for control of roughstalk bluegrass. Initial studies were conducted during 2005 in Illinois and Indiana and follow-up studies in 2006 in Indiana, Illinois, South Dakota (partial shade and full sun), and Wisconsin. Applications starting in the warmer temperatures of late May and June 2005 were more effective …

Cell Wall Proteome In The Maize Primary Root Elongation Zone. Ii. Region-Specific Changes In Water Soluble And Lightly Ionically Bound Proteins Under Water Deficit1[W][Oa], Jinming Zhu, Sophie Alvarez, Ellen L. Marsh, Mary E. Lenoble, In-Jeong Cho, Mayandi Sivaguru, Sixue Chen, Henry T. Nguyen, Yajun Wu, Daniel P. Schachtman, Robert E. Sharp

Department of Agronomy and Horticulture: Faculty Publications

Previous work on the adaptation of maize (Zea mays) primary roots to water deficit showed that cell elongation is maintained preferentially toward the apex, and that this response involves modification of cell wall extension properties. To gain a comprehensive understanding of how cell wall protein (CWP) composition changes in association with the differential growth responses to water deficit in different regions of the elongation zone, a proteomics approach was used to examine water soluble and loosely ionically bound CWPs. The results revealed major and predominantly region-specific changes in protein profiles between well-watered and water-stressed roots. In total, 152 …

Climate Change, Biofuels, And Global Food Security, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

There is a new urgency to improve the accuracy of predicting climate change impact on crop yields because the balance between food supply and demand is shifting abruptly from surplus to deficit. This reversal is being driven by a rapid rise in petroleum prices and, in response, a massive global expansion of biofuel production from maize, oilseed, and sugar crops. Soon the price of these commodities will be determined by their value as feedstock for biofuel rather than their importance as human food or livestock feed [1]. The expectation that petroleum prices will remain high and supportive government policies in …

A Dialogue On Interdisciplinary Collaboration To Bridge The Gap Between Plant Genomics And Crop Sciences, P. C. Struik, Kenneth G. Cassman, M. Koornneef

Department of Agronomy and Horticulture: Faculty Publications

In the future, more food needs to be produced with increasingly scarce natural resources. Genomics can play a key role in accelerating yield gains because it helps to improve our understanding of genetic traits and assists in breeding for better crop performance. The scientific muscle of genomics attracted tremendous research investments, but the efficiency with which these investments are paying off is still low. How can we accelerate the application of molecular genetics to our understanding of crop physiology and subsequently to crop improvement? The missing link is a more detailed understanding of the effects of gene function on crop …

Forage Yields From 2006-2007 Annual Ryegrass Variety Trial, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Introduction:

In an effort to assist livestock producers in Oklahoma and Texas judge variety performance, the Noble Foundation has held trials to determine forage yields of commercially available varieties and experimental strains of annual ryegrass. The objective of this report is to summarize forage yields from the 2006-2007 trial.

Materials and Methods

The test was conducted on a Wilson silt loam soil at the Noble Foundation Headquarters Farm near Ardmore, Okla. The trial consisted of 37 entries; 28 were commercially available varieties and nine were experimental strains. Twelve sources contributed entries to the trial (Table 1). The entries were seeded …

Forage Yields From 2006-2007 Small Grains Variety Trial, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Introduction

In an effort to assist producers in Oklahoma and Texas judge variety performance, the Noble Foundation has held trials to determine forage and grain yields of commercially available varieties and advanced experimental lines of small grains. The objective of this report was to summarize forage yields of commercial varieties in the 2006-2007 trials.

Trial Procedures

The small grains test was conducted at the Noble Foundation Headquarters Farm (HQF) near Ardmore and the Red River Demonstration and Research Farm (RRF) near Burneyville, Okla. Soils were a Heiden clay at HQF and a Minco fine sandy loam at RRF. Twelve sources …

Finding Value In Switchgrass Today Through Cattle, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass has future potential in the Southern Plains as a dedicated cellulosic biofuels crop. In the near and intermediate terms, an economically viable use for switchgrass needs to be found. In May 2007, the Noble Foundation Agricultural Division successfully established a 30-acre field of switchgrass at the Red River Demonstration and Research Farm. Beginning in April 2008, we will evaluate the utilization and value of switchgrass for stocker cattle. Switchgrass may have value for stockers because of its early spring availability, high yields, perennial life form, wide adaptability and low fertilization requirements.

Second-year stands of switchgrass become available for grazing …

Plant Species Richness In Relation To Pasture Position, Management, And Scale, John A. Guretzky, Kenneth J. Moore, C. Lee Burras, E. Charles Brummer

Department of Agronomy and Horticulture: Faculty Publications

The objective of this research was to describe how landscape position, grazing management, and scale affected overall plant species richness and species richness per functional group in temperate pastures located in the central United States. The effects and interactions of summit, backslope, and toeslope positions and continuous, rotational, and nongrazed stocking systems on species richness were examined at sample scales of 0.18 m² and 4.5 m². Landscape position explained 40–63% of species richness variation at 0.18 m² compared to 3–26% at 4.5 m² for overall, perennial, perennial grass, vegetative-spreading grass, perennial herb, and perennial N …

Nbs1 Mediates Atr-Dependent Rpa Hyperphosphorylation Following Replication-Fork Stall And Collapse, Karoline C. Manthey, Stephen Opiyo, Jason G. Glanzer, Diana Dimitrova, James Elliott, Gregory G. Oakley

Department of Agronomy and Horticulture: Faculty Publications

Post-translational phosphorylation of proteins provides a mechanism for cells to switch on or off many diverse processes, including responses to replication stress. Replication-stress-induced phosphorylation enables the rapid activation of numerous proteins involved in DNA replication, DNA repair and cell cycle checkpoints, including replication protein A (RPA). Here, we report that hydroxyurea (HU)-induced RPA phosphorylation requires both NBS1 (NBN) and NBS1 phosphorylation. Transfection of both phosphospecific and nonphosphospecific anti-NBS1 antibodies blocked hyperphosphorylation of RPA in HeLa cells. Nijmegen breakage syndrome (NBS) cells stably transfected with an empty vector or with S343A-NBS1 or S278A/S343A phospho-mutants were unable to hyperphosphorylate RPA in DNA-damage-associated …

Publishing Ltd Whole-Plant Mineral Partitioning Throughout The Life Cycle In Arabidopsis Thaliana Ecotypes Columbia, Landsberg Erecta, Cape Verde Islands, And The Mutant Line Ysl1ysl3, Brian M. Waters, Michael A. Grusak

Department of Agronomy and Horticulture: Faculty Publications

• Minimal information exists on whole-plant dynamics of mineral flow through Arabidopsis thaliana or on the source tissues responsible for mineral export to developing seeds. Understanding these phenomena in a model plant could help in the development of nutritionally enhanced crop cultivars. • A whole-plant partitioning study, using sequential harvests, was conducted to characterize growth and mineral concentrations and contents of rosettes, cauline leaves, stems, immature fruit, mature fruit hulls, and seeds of three WT lines (Col-0, Ler, and Cvi) and one mutant line (Col-0::ysl1ysl3). • Shoot mineral content increased throughout the life cycle for all minerals, although tissue-specific mineral …

Array-Based Genotyping And Expression Analysis Of Barley Cv. Maythorpe And Golden Promise, Harkamal Walia, Clyde Wilson, Pascal Condamine, Abdelbagi M. Ismail, Jin Xu, Xinping Cui, Timothy J. Close

Department of Agronomy and Horticulture: Faculty Publications

Background: Golden Promise is a salt-tolerant spring barley closely related to Maythorpe. Salt tolerance in Golden Promise has been attributed to a single mutation at the Ari-e locus (on 5H) resulting from irradiation of Maythorpe. Golden Promise accumulates lower shoot Na⁺ compared to Maythorpe when growing under saline conditions. This study focused on elucidating the genetic basis and mechanisms involved in this difference. Results: The level of polymorphism between the two genotypes was explored using the Barley1 GeneChip for single feature polymorphisms (SFPs) and an oligonucleotide pool assay for single nucleotide polymorphisms (SNPs). Polymorphism analyses revealed three haplotype blocks …