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Department of Agronomy and Horticulture: Faculty Publications

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Articles 1141 - 1170 of 1713

Full-Text Articles in Life Sciences

Growth And Yield Of Snap Beans As Affected By Wind Protection And Microclimate Changes Due To Shelterbelts And Planting Dates, Laurie Hodges, Mohd Nazip Suratman, James R. Brandle, Kenneth G. Hubbard Aug 2004

Growth And Yield Of Snap Beans As Affected By Wind Protection And Microclimate Changes Due To Shelterbelts And Planting Dates, Laurie Hodges, Mohd Nazip Suratman, James R. Brandle, Kenneth G. Hubbard

Department of Agronomy and Horticulture: Faculty Publications

The effects of wind protection on growth and total and marketahle yields of snap bean (Phaseolus vulgaris L.) planted at 2-week intervals through the 1994 and 1995 growing seasons were examined. Research was conducted under nonirrigated conditions at the Shelterbelt Research Area, Univ, of Nebraska Agricultural Research and Development Center (ARDC) near Mead. 'Strike' (white-seeded) and 'Rushmore' (dark-seeded) were planted in locations sheltered from wind stress hy tree windbreaks (shelterbelts) and in locations exposed to normal winds using a randomized complete-block design with a split-split plot arrangement of treatments. Air temperature, soil temperature, humidity, wind speed, and wind direction …

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Rice Yields Decline With Higher Night Temperature From Global Warming, Shaobing Peng, Jianliang Huang, John Sheehy, Rebecca C. Laza, Romeo M. Visperas, Xuhua Zhong, Grace S. Centeno, Gurdev S. Khush, Kenneth G. Cassman Jul 2004

Rice Yields Decline With Higher Night Temperature From Global Warming, Shaobing Peng, Jianliang Huang, John Sheehy, Rebecca C. Laza, Romeo M. Visperas, Xuhua Zhong, Grace S. Centeno, Gurdev S. Khush, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

The impact of projected global warming on crop yields has been evaluated by indirect methods using simulation models. Direct studies on the effects of observed climate change on crop growth and yield could provide more accurate information for assessing the impact of climate change on crop production. We analyzed weather data at the International Rice Research Institute Farm from 1979 to 2003 to examine temperature trends and the relationship between rice yield and temperature by using data from irrigated field experiments conducted at the International Rice Research Institute Farm from 1992 to 2003. Here we report that annual mean maximum …

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Characterization Of Humic Acid Fractions Improves Estimates Of Nitrogen Mineralization Kinetics For Lowland Rice Soils, Nguyen Bao Ve, D. C. Olk, Kenneth G. Cassman Jul 2004

Characterization Of Humic Acid Fractions Improves Estimates Of Nitrogen Mineralization Kinetics For Lowland Rice Soils, Nguyen Bao Ve, D. C. Olk, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen mineralization in irrigated lowland rice (Oryza sativa L.) soils is poorly predicted by total soil C and N. To improve its prediction, two humic acid fractions were extracted with NaOH from lowland rice soils of Vietnam and the Philippines to evaluate their influence on N mineralization kinetics during 84-d anaerobic incubations. Indicative of young organic matter, the mobile humic acid (MHA) fraction had a smaller C/N ratio and optical density at 465 nm (E4) than did the calcium humate (CaHA) fraction, which was extracted after removal of polyvalent cations from the soil. Nitrogen contents of both …

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Nitrogen Mineralization From Humic Acid Fractions In Rice Soils Depends On Degree Of Humification, Bao Ve Nguyen, D. C. Olk, Kenneth G. Cassman Jul 2004

Nitrogen Mineralization From Humic Acid Fractions In Rice Soils Depends On Degree Of Humification, Bao Ve Nguyen, D. C. Olk, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Although the chemical nature of soil organic matter (SOM) is thought to affect the mineralization rate of N bound in SOM, little direct evidence exists for such effects. To test the hypothesis that the N mineralization rate is affected by the degree of SOM humification, we added equivalent amounts of humic acid (HA) N as either the labile mobile humic acid (MHA) fraction or the more humified cal- cium humate (CaHA) fraction to two lowland rice (Oryza sativa L.) soils, which were subsequently incubated under anaerobic conditions for 6 wk. The HA fractions had been chemically extracted from seven …

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A New Integrated Genetic Linkage Map Of The Soybean, Q.J. Song, L.F. Marek, R.C. Shoemaker, K.G. Lark, V.C. Concibido, X. Delannay, James E. Specht, P.B. Cregan Jun 2004

A New Integrated Genetic Linkage Map Of The Soybean, Q.J. Song, L.F. Marek, R.C. Shoemaker, K.G. Lark, V.C. Concibido, X. Delannay, James E. Specht, P.B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

A total of 391 simple sequence repeat (SSR) markers designed from genomic DNA libraries, 24 derived from existing GenBank genes or ESTs, and five derived from bacterial artificial chromosome (BAC) end sequences were developed. In contrast to SSRs derived from EST sequences, those derived from genomic libraries were a superior source of polymorphic markers, given that the mean number of tandem repeats in the former was significantly less than that of the latter (P<0.01). The 420 newly developed SSRs were mapped in one or more of five soybean mapping populations: ‘Minsoy’ × ‘Noir 1’, ‘Minsoy’ × ‘Archer’, ‘Archer’ × ‘Noir 1’, ‘Clark’ × ‘Harosoy’, and A81-356022 × PI468916. The JoinMap software package was used to combine the five maps into an integrated genetic map spanning 2,523.6 cM of Kosambi map distance across 20 linkage groups that contained 1,849 markers, including 1,015 SSRs, 709 RFLPs, 73 RAPDs, 24 classical traits, six AFLPs, ten isozymes, and 12 others. The number of new SSR markers added to each linkage group ranged from 12 to 29. In the integrated map, the ratio of SSR marker number to linkage group map distance did not differ among 18 of the 20 linkage groups; however, the SSRs were not uniformly spaced over a linkage group, clusters of SSRs with very limited recombination were frequently present. These clusters of SSRs may be indicative of gene-rich regions of soybean, as has been suggested by a number of recent studies, indicating the significant association of genes and SSRs. Development of SSR markers from map-referenced BAC clones was a very effective means of targeting markers to marker-scarce positions in the genome.

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Stability Of The Allergenic Soybean Kunitz Trypsin Inhibitor, Robin Roychaudhuri, Gautam Sarath, Michael G. Zeece, John P. Markwell May 2004

Stability Of The Allergenic Soybean Kunitz Trypsin Inhibitor, Robin Roychaudhuri, Gautam Sarath, Michael G. Zeece, John P. Markwell

Department of Agronomy and Horticulture: Faculty Publications

The soybean Kunitz trypsin inhibitor (SKTI) is a 21.5 kDa allergenic protein that belongs to the family of all antiparallel h-sheet proteins that are highly resistant to thermal and chemical denaturation. Spectroscopic and biochemical techniques such as circular dichroism (CD), ANS fluorescence and proteolysis were used to study its molecular structure under denaturing conditions such as acid and heat to which these allergens are commonly exposed during food processing. Reduction of native SKTI leads to its complete and rapid proteolysis by pepsin in simulated gastric fluid (SGF). Limited proteolysis with chymotrypsin during renaturation after heating showed that the native structure …

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Hybrid-Maize—A Maize Simulation Model That Combines Two Crop Modeling Approaches, H. S. Yang, A. Dobermann, John L. Lindquist, Daniel T. Walters, Timothy J. Arkebauer, Kenneth G. Cassman May 2004

Hybrid-Maize—A Maize Simulation Model That Combines Two Crop Modeling Approaches, H. S. Yang, A. Dobermann, John L. Lindquist, Daniel T. Walters, Timothy J. Arkebauer, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

A new maize (Zea mays L.) simulation model, Hybrid-Maize, was developed by combining the strengths of two modeling approaches: the growth and development functions in maize-specific models represented by CERES- Maize, and the mechanistic formulation of photosynthesis and respiration in generic crop models such as INTERCOM and WOFOST. It features temperature-driven maize phenological development, vertical canopy integration of photosynthesis, organ-specific growth respiration, and temperature-sensitive maintenance respiration. The inclusion of gross assimilation, growth respiration and maintenance respiration makes the Hybrid- Maize model potentially more responsive to changes in environmental conditions than models such as CERES-Maize. Hybrid-Maize also requires fewer genotype-specific …

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Feasibility Of Site-Specific Management Of Corn Hybrids And Plant Densities In The Great Plains, J.F. Shanahan, Thomas A. Doerge, Jerry J. Johnson, Merle F. Vigil Apr 2004

Feasibility Of Site-Specific Management Of Corn Hybrids And Plant Densities In The Great Plains, J.F. Shanahan, Thomas A. Doerge, Jerry J. Johnson, Merle F. Vigil

Department of Agronomy and Horticulture: Faculty Publications

The goal of this research was to determine the potential for use of site-specific management of corn hybrids and plant densities in dryland landscapes of the Great Plains by determining (1) within-field yield variation, (2) yield response of different hybrids and plant densities to variability, and (3) landscape attributes associated with yield variation. This work was conducted on three adjacent fields in eastern Colorado during the 1997, -98, and -99 seasons. Treatments consisted of a combination of two hybrids (early and late maturity) and four plant densities (24,692, 37,037, 49,382 and 61,727 plants ha-1) seeded in replicated long …

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Agronomic Ufos, Thomas R. Sinclair, Kenneth G. Cassman Apr 2004

Agronomic Ufos, Thomas R. Sinclair, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Science is challenged from time-to-time by claims that are completely outside the usual boundaries of observation and experience. Reports of flying saucers (unidentified flying objects) and creationism’s counter to evolution are two examples that fall into this category. Credentialed scientists can themselves become the victims of such phenomena when their research results are not evaluated through anonymous peer review as part of publication. The cold fusion debacle of a few years ago is an example of such a bypass of peer evaluation.

Unfortunately, agronomic science is not immune to such problems, particularly as they relate to claims of miraculously high …

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Appropriateness Of Management Zones For Characterizing Spatial Variability Of Soil Properties And Irrigated Corn Yields Across Years, Aaron R. Schepers, J.F. Shanahan, Mark A. Liebig, James S. Schepers, Sven Johnson, Ariovaldo Luchiari Jr. Feb 2004

Appropriateness Of Management Zones For Characterizing Spatial Variability Of Soil Properties And Irrigated Corn Yields Across Years, Aaron R. Schepers, J.F. Shanahan, Mark A. Liebig, James S. Schepers, Sven Johnson, Ariovaldo Luchiari Jr.

Department of Agronomy and Horticulture: Faculty Publications

Recent precision-agriculture research has focused on use of management zones (MZ) as a method for variable application of inputs like N. The objectives of this study were to determine (i) if landscape attributes could be aggregated into MZthat characterize spatial varia- tion in soil chemical properties and corn yields and (ii) if temporal variability affects expression of yield spatial variability. This work was conducted on an irrigated cornfield near Gibbon, NE. Five landscape attributes, including a soil brightness image (red, green, and blue bands), elevation, and apparent electrical conductivity, were acquired for the field.Ageoreferenced soil-sampling scheme was used to determine …

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Prediction Of Leaf/Stem Ratio Using Near-Infrared Reflectance Spectroscopy (Nirs): A Technical Note, Alexander J. Smart, Walter H. Schacht, Lowell E. Moser, Jerry D. Volesky Feb 2004

Prediction Of Leaf/Stem Ratio Using Near-Infrared Reflectance Spectroscopy (Nirs): A Technical Note, Alexander J. Smart, Walter H. Schacht, Lowell E. Moser, Jerry D. Volesky

Department of Agronomy and Horticulture: Faculty Publications

Leaf/stem ratio of grass stands is an important factor affecting diet selection, quality, and forage intake. Determination of leaf/stem ratio involves a labor-intensive process of hand separating leaf and stem fractions. Our objectives in this study were to evaluate leaf/stem ratio prediction using near-infrared reflectance spectroscopy (NIRS) in monocultures of big bluestem (Andropogon gerardii Vitman), switch- grass (Panicum virgatum L.), intermediate wheatgrass [Thinopyrum intermedian (Host) Barkw. & D.R. Dewey], and smooth bromegrass (Bromus inermis Leyss.). Samples of each species were hand-clipped from monocultures at four locations throughout Nebraska in the 1997 and 1998 growing seasons. Ground …

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Forage & Grazing Lands: Morphological Characteristics Of Big Bluestem And Switchgrass Plants Divergently Selected For Seedling Tiller Number, Alexander J. Smart, Lowell E. Moser, Kenneth P. Vogel Jan 2004

Forage & Grazing Lands: Morphological Characteristics Of Big Bluestem And Switchgrass Plants Divergently Selected For Seedling Tiller Number, Alexander J. Smart, Lowell E. Moser, Kenneth P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

Selection at the seedling stage in grass breeding would be useful if seedling traits were correlated to desired agronomic traits of mature plants. Objectives of this study were to determine if seedlings from big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicumvirgatum L.) populations that differ genetically in seedling tiller num- ber differ in mature plant (i) morphological characteristics, (ii) forage yield managed by a three-cut harvest system or a single end-of-season harvest, and (iii) leaf elongation rate. Field experiments were conducted on a Kennebec silt loam soil (fine-silty, mixed, superactive, mesic Cumulic Hapludolls). In addition, greenhouse studies were …

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Establishing Effects Of Application Of Swine Manure On Crop Leaf Damage To Growing Crops, Charles Shapiro, University Of Nebraska-Lincoln Jan 2004

Establishing Effects Of Application Of Swine Manure On Crop Leaf Damage To Growing Crops, Charles Shapiro, University Of Nebraska-Lincoln

Department of Agronomy and Horticulture: Faculty Publications

Swine manure from a below barn storage facility was applied to growing corn and soybeans to determine phytotoxic effects. The manure had an electrical conductivity of around 20 mmhos/cm and was diluted for treatment at full, half, quarter and none. The manure mixtures were applied at a rate of 0.5 in/acre using a procedure that wet the foliage three times in a 15-minute time span. Manure mixtures were applied at V7 and V14 for corn and V3 and R1 for soybeans. Phytotoxic effects were shown at the high rate for both crops, but soybeans were killed at the early application …

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Seed Quality Qtl In A Prominent Soybean Population, D. L. Hyten Jr., V. R. Pantalone, C. E. Sams, A. M. Saxon, D. Landau-Ellis, T. R. Stefaniak, M. E. Schmidt Jan 2004

Seed Quality Qtl In A Prominent Soybean Population, D. L. Hyten Jr., V. R. Pantalone, C. E. Sams, A. M. Saxon, D. Landau-Ellis, T. R. Stefaniak, M. E. Schmidt

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is a versatile crop due to its multitude of uses as a high protein meal and vegetable oil. Soybean seed traits such as seed protein and oil concentration and seed size are important quantitative traits. The objective of this study was to identify representative protein, oil, and seed size quantitative trait loci (QTL) in soybean. A recombinant inbred line (RIL) population consisting of 131 F6-derived lines was created from two prominent ancestors of North American soy-beans (‘Essex’ and ‘Williams’) and the RILs were grown in six environments. One hundred simple sequence repeat (SSR) markers …

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Factors Affecting The Realized Niche Of Common Sunflower (Helianthus Annuus) In Ridge-Tillage Corn, Michael G. Burton, David A. Mortensen, David B. Marx, John L. Lindquist Jan 2004

Factors Affecting The Realized Niche Of Common Sunflower (Helianthus Annuus) In Ridge-Tillage Corn, Michael G. Burton, David A. Mortensen, David B. Marx, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Because soil characteristics and weed densities vary within agricultural landscapes, determining which subfield areas are most favorable to weed species may aid in their management. Field and greenhouse studies were conducted to determine whether subfield environments characterized by higher soil organic carbon (SOC), or ridge vs. furrow microsites, affect common sunflower seed germination after winter burial, seedling emergence, or the control afforded by a preemergence herbicide in a ridge-tillage corn production system. Among seeds buried in situ during winter months and germinated in the laboratory, no differences in common sunflower seed germination or mortality were detected between high-SOC (1.8% mean) …

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Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams Jan 2004

Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams

Department of Agronomy and Horticulture: Faculty Publications

Altering FA content in soybean [Glycine max (L.) Merr.] oil for improved functionality is a research goal of many soybean breeders. Several of the genes that alter palmitic, stearic, oleic, linoleic, and linolenic acids are modifier genes with small effects, causing these FA traits to act as quantitative traits. The objective of this study was to identify modifier FA quantitative trait loci (QTL) in soybean. A recombinant inbred line population was created from two prominent ancestors of currently avail-able U.S. cultivars (Essex and Williams) and grown in five environments. One hundred simple se-quence repeat markers spaced throughout the genome …

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Old-Field Grassland Successional Dynamics Following Cessation Of Chronic Disturbance, Susan Tunnell, David Engle, Eric Jorgensen Jan 2004

Old-Field Grassland Successional Dynamics Following Cessation Of Chronic Disturbance, Susan Tunnell, David Engle, Eric Jorgensen

Department of Agronomy and Horticulture: Faculty Publications

Question: Does increasing i>Festuca canopy cover reduce plant species richness and, therefore, alter plant community composition and the relationship of litter to species richness in old-field grassland?
Location: Southeastern Oklahoma, USA.
Methods: Canopy cover by species, species richness, and litter mass were collected within an old-field grassland site on 16, 40 m x &#;40 m plots. Our study was conducted during the first three years of a long-term study that investigated the effects of low-level nitrogen enrichment and small mammal herbivory manipulations.
Results: Succession was altered by an increase in abundance of Festuca over the 3-yr study period. Species …

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Resource Allocation In A Breeding Program For Phosphorus Concentration In Maize Grain, Brandon M. Wardyn, W. Ken Russell Jan 2004

Resource Allocation In A Breeding Program For Phosphorus Concentration In Maize Grain, Brandon M. Wardyn, W. Ken Russell

Department of Agronomy and Horticulture: Faculty Publications

When beef cattle (Bos taurus) are fed grain of maize (Zea mays L.) in which the concentration of phosphorus (P) exceeds the animal’s need for this element, the excess P is excreted in the feces. Spreading this manure on cropland increases the potential for P pollution of surface waters by run-off. Experiments were undertaken to determine the relative magnitudes of genotypic and nongenotypic variances of P concentration in maize grain (P-Gr) to assess the ability to select maize genotypes in which this trait more closely matches the dietary need of beef cattle. Genetic variability was found in …

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Changes In Nitrogen Use Efficiency And Soil Quality After Five Years Of Managing For High Yield Corn And Soybean, Timothy J. Arkebauer, Achim R. Dobermann, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang Jan 2004

Changes In Nitrogen Use Efficiency And Soil Quality After Five Years Of Managing For High Yield Corn And Soybean, Timothy J. Arkebauer, Achim R. Dobermann, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang

Department of Agronomy and Horticulture: Faculty Publications

Average corn grain yields in the USA have increased linearly at a rate of 1.7 bu/acre over the past 35 years with a national yield average of 140 bu/acre. Corn yield contest winners and simulation models, however, indicate there is ~100 bu/a in exploitable corn yield gap. Four years (1999-2002) of plant development, grain yield and nutrient uptake were compared in intensive irrigated maize systems representing (a) recommended best management practices for a yield goal of 200 bu/acre (M1) and (b) intensive management aiming at a yield goal of 300 bu/acre (M2). For each management level, three levels of plant …

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Windbreaks In North American Agricultural Systems, James R. Brandle, Laurie Hodges, Xinhua H. Zhou Jan 2004

Windbreaks In North American Agricultural Systems, James R. Brandle, Laurie Hodges, Xinhua H. Zhou

Department of Agronomy and Horticulture: Faculty Publications

Windbreaks are a major component of successful agricultural systems throughout the world. The focus of this chapter is on temperate-zone, commercial, agricultural systems in North America, where windbreaks contribute to both producer profitability and environmental quality by increasing crop production while simultaneously reducing the level of off-farm inputs. They help control erosion and blowing snow, improve animal health and survival under winter conditions, reduce energy consumption of the farmstead unit, and enhance habitat diversity, providing refuges for predatory birds and insects. On a larger landscape scale windbreaks provide habitat for various types of wildlife and have the potential to contribute …

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Common Lambsquarters (Chenopodium Album) Interference With Corn Across The North-Central United States, David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra, John L. Lindquist Jan 2004

Common Lambsquarters (Chenopodium Album) Interference With Corn Across The North-Central United States, David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Variation in crop–weed interference relationships has been shown for a number of crop–weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the north-central United States.

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Glyphosate Efficacy On Velvetleaf Varies With Application Time Of Day, Aaron L. Waltz, Alex R. Martin, Fred W. Roeth, John L. Lindquist Jan 2004

Glyphosate Efficacy On Velvetleaf Varies With Application Time Of Day, Aaron L. Waltz, Alex R. Martin, Fred W. Roeth, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Field and growth chamber experiments determined the efficacy of temporal glyphosate applications on velvetleaf. Glyphosate was applied post-emergence to velvetleaf periodically before and during light and after dark. In 1999, glyphosate at 840 g ae/ha applied before sunrise and after midday provided 54 and 100% velvetleaf control, respectively. In 2000, glyphosate at 840 g/ha applied before sunrise, midday, and after sunset provided 69, 100, and 37% velvetleaf control, respectively. In the growth chamber, glyphosate at 840 g/ha applied before or after light reduced velvetleaf biomass 15 to 20% or 32 to 47%, respectively, and reduced velvetleaf height 24% or 45 …

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Windbreaks, Robert J. Rouse, Laurie Hodges Jan 2004

Windbreaks, Robert J. Rouse, Laurie Hodges

Department of Agronomy and Horticulture: Faculty Publications

Windbreaks are an important and often overlooked component of a plasticulture system. They provide benefits regardless of where you farm or what crops you are raising. When wind protection is included in a plasticulture production system, crops benefit from less wind stress and an improved microclimate for growth and development. There is less crop injury due to soil abrasion or wind-whipping of plants, less extreme soil temperature fluctuations, and improved soil warming. Wind protection often results in earlier yields of higher-quality crops.

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Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger Jan 2004

Predicting Phenological Development In Winter Wheat, Qingwu Xue, Albert Weiss, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Accurate prediction of phenological development is important in the winter wheat Triticum aestivum agroecosystem. From a practical perspective, applications of pesticides and fertilizers are carried out at specific phenological stages. In crop-simulation modeling, the prediction of yield components (kernel number and kernel weight) and wheat-grain yield relies on accurate prediction of phenology. In this study, a nonlinear multiplicative model by Wang & Engel (WE) for predicting phenological development in differing winter wheat cultivars was evaluated using data from a 3 yr field experiment. In the vegetative phase (emergence to anthesis) the daily development rate (r) was simulated based on the …

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Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer Jan 2004

Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer

Department of Agronomy and Horticulture: Faculty Publications

The in-season estimation of crop stresses which have the potential of adversely affecting crop yield and/or quality could allow producers to make in-season management decisions to correct for the particular stress. A field study was conducted to evaluate the use of multispectral imagery for estimating corn (Zea mays L.) grain yield, in-season biomass and nitrogen (N) concentration under varying N and drought stresses. The experiment was a split-plot design with three replications using a factorial arrangement of treatments. Three irrigation (whole-plot) treatments included dry land, irrigation based on 0.5, and full evapotranspiration (ET). Sub-plot treatments included five N …

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Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra Jan 2004

Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra

Department of Agronomy and Horticulture: Faculty Publications

In sorghum, ingress of Cochliobolus heterostrophus stimulates the synthesis of 3-deoxyanthocyanidins that act as phytoalexins. Apigeninidin and luteolinidin are two major phytoalexins induced in the first 24 h after infection. In an attempt to understand genetic regulation of the biosynthesis of sorghum phytoalexins, we isolated a differentially expressed partial cDNA. Characterization and comparison showed that this cDNA sequence corresponds to a putative flavonoid 3’-hydroxylase. Full length sequence characterization allowed us to establish that the sorghum putative f3’h cDNA encodes a peptide of 517 amino acids that has domains conserved among cytochrome P450 proteins functioning in …

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Application Of Sequence-Related Amplified Polymorphism Markers For Characterization Of Turfgrass Species, Hikmet Budak, Bob Shearman, Roch E. Gaussoin, Ismail M. Dweikat Jan 2004

Application Of Sequence-Related Amplified Polymorphism Markers For Characterization Of Turfgrass Species, Hikmet Budak, Bob Shearman, Roch E. Gaussoin, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

A simple marker technique called sequence-related amplified polymorphism (SRAP) provides a useful tool for estimation of genetic diversity and phenetic relationships in natural and domesticated populations. Previous studies and our initial screen show SRAP is highly polymorphic and more informative when compared to AFLP, RAPD and SSR markers. In this study, applicability of the SRAP markers to obtain an overview of genetic diversity and phenetic relationships resent among cool-season (C3) and warm-season (C4) turfgrass species and their relationship with other Gramineae species were tested. Phenetic trees based on genetic similarities (UPGMA, N-J) were consistent with known taxonomic relationships. In some …

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Heritability Of The Resistance To Potato Leafhopper In Dry Bean, J.W. Gonzales, Dermot P. Coyne, Dale T. Lindgren, D. Schaaf, Kent M. Eskridge Jan 2004

Heritability Of The Resistance To Potato Leafhopper In Dry Bean, J.W. Gonzales, Dermot P. Coyne, Dale T. Lindgren, D. Schaaf, Kent M. Eskridge

Department of Agronomy and Horticulture: Faculty Publications

The potato leafhopper (PLH), Empoasca fabae Harris is the most important Empoasca species attacking dry beans (Phaseolus vulgaris L.) in North America. The objective of this study was to determine the heritability (h2) of PLH injury based on parent-offspring regression analysis of F3 means on individual F2 plants derived from crosses of pinto 'Sierra' (resisant) x great northern 'Starlight' (susceptible), and black bean 'Tacarigua' (resistant) x 'Starlight' (susceptible). Low narrow-sense heritability values of 0.29 ± 0.06 ± 0.28 ± 0.10, respectively, were obtained for the above crosses. The low narrow-sense heritability estimates indicated large environmental …

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Random Amplified Polymorphic Dna (Rapd) Analysis Of Long-Term Cultured Hybrid Hazelnut, Mehmet Nuri Nas, Nedim Mutle, Paul Read Jan 2004

Random Amplified Polymorphic Dna (Rapd) Analysis Of Long-Term Cultured Hybrid Hazelnut, Mehmet Nuri Nas, Nedim Mutle, Paul Read

Department of Agronomy and Horticulture: Faculty Publications

RAPD and phenotypic analysis were conducted to assess clonal stability of hazelnuts generated from axillary buds cultured in vitro for long-term. The nuts produced on in vitro-propagated plants were indistinguishable from those of donor plants. With the exception of rare horizontal (plagiotropic) growth, all in vitro-propagated plants exhibited phenotypes similar to those of donor plants. RAPD analysis did not reveal any somaclonal variation between donor plants from which in vitro cultures were initiated and micropropogated plants (6-year cultures), and no somaclonal variation was detected among in vitro propogated plants. However, polymorphism (15.6%) was detected between the parent plant and its …

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Improved Rooting And Acclimatization Of Micropropagated Hazelnut Shoots, Mehmet Nuri Nas, Paul Read Jan 2004

Improved Rooting And Acclimatization Of Micropropagated Hazelnut Shoots, Mehmet Nuri Nas, Paul Read

Department of Agronomy and Horticulture: Faculty Publications

Microshoots of four hazelnut genotypes grown in vitro on Nas and Read medium (NRM) containing various combinations of CuSO4 ∙ 5H2O and myo-inositol were successfully rooted and acclimatized ex vitro without any need of in vitro hardening treatments. Dipping of shoot bases in 1000 ppm indole-3-butyric acid (IBA) solution for 5 or 10 seconds followed by placement of shoots in plant growth regulator free NRM gave rise to formation of roots as early as 8 days. Shoots treated for 5 and 10 seconds rooted similarly, and depending on genotype, 88%-98% rooting was observed within 15 days after …

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