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Pollination Biology Of A Disjunct Population Of The Endangered Sandhills Endemic Penstemon Haydenii S. Wats. (Scrophulariaceae) In Wyoming, Usa, V. J. Tepedino, T. L. Griswold, T.R. Toler, B. A. Bradley, J. L. Hawk

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

We studied the breeding system and flower visitors of the endangered plant, Penstemon haydenii, at several south-central Wyoming, USA occurrences. In agreement with earlier studies of the species 300 km to the east in Nebraska, we found Wyoming plants to be self-incompatible and pollinator-dependent for sexual reproduction. Flower visitors were several species of native bees in the families Apidae (particularly bumblebees), Halictidae (small sweat bees), and Megachilidae (especially in the genus Osmia); and the masarid wasp Pseudomasaris vespoides. Especially important was Osmia brevis, an abundant megachilid bee, and one of only two species (the sweat bee …

Growth And Pubertal Development Of F1 Bulls From Hereford, Angus, Norwegian Red, Swedish Red And White, Friesian, And Wagyu Sires, E. Casas, D. Lunstra, Larry V. Cundiff, Johny Joe Ford

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

The objective of the study was to characterize body growth, testicular development, and puberty from 8 to 14 mo of age in bulls (n = 120) produced by mating sires from Hereford, Angus, Norwegian Red, Swedish Red and White, Friesian, and Wagyu breeds to MARC III (¹⁄₄ Hereford, ¹⁄₄ Angus, ¹⁄₄ Red Poll, and ¹⁄₄ Pinzgauer) cows. Traits evaluated were birth weight, weaning weight (at 215 d), yearling weight, ADG from 8 to 14 mo of age, paired testicular volume growth from 8 to 14 mo of age, age at puberty (determined by production of 50 × 10⁶ sperm …

Mitigation Of Shallow Groundwater Nitrate In A Poorly Drained Riparian Area And Adjacent Cropland, Jennifer H. Davis, Stephen M. Griffith, William R. Horwath, Jeffrey J. Steiner, David D. Myrold

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

Riparian ecosystems, through their unique position in the agricultural landscape and ability to influence nutrient cycles, can potentially reduce NO₃ loading to surface and ground waters. The purpose of this study was to determine the fate of NO₃ in shallow groundwater moving along a lateral flowpath from a grass seed cropping system through an undisturbed mixed-species herbaceous riparian area. Soil A (30–45 cm) and C horizon (135–150 cm) NO₃, dissolved oxygen, and nitrous oxide concentrations were significantly higher in the cropping system than the adjacent riparian area. Nitrate concentrations in both horizons of the riparian soil …

The Original Usda-Ars Experimental Watersheds In Texas And Ohio: Contributions From The Past And Visions For The Future, R. D. Harmel, J. V. Bonta, C. W. Richardson

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

The USDA Soil Conservation Service (USDA‐SCS) realized the importance of understanding hydrologic processes on agricultural fields and watersheds in the mid‐1930s. Based on this realization, the research program of the Hydrologic Division of SCS established three experimental watersheds across the U.S. to analyze the impact of landuse practices on soil erosion, flood events, water resources, and the agricultural economy. Two of the original watersheds remain in operation today within the USDA Agricultural Research Service (USDA‐ARS): the Blacklands Experimental Watershed (now the Grassland, Soil and Water Research Laboratory) near Riesel, Texas, and the North Appalachian Experimental Watershed near Coshocton, Ohio. These …

Dry Weight And Nitrogen Content Of Chickpea And Winter Wheat Grown In Pots For Three Rotations, James E. Bidlack, Charles T. Mackown, Srinivas C. Rao

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

Chickpea [Cicer arietinum (L.)] cultivars ‘ICCV-2’ and ‘Sarah’ were studied along with a control, multistrain, TAL 1148, and TAL 480 Bradyrhizobium strains to determine the effect(s) of cultivar and inoculum on dry weight (DW) and nitrogen (N) content of the legume, as well as soil mineral N, DW, and N content of wheat [Triticum aestivum (L.) emend. Thell.] in a continuous wheat-legume rotation. Chickpeas were planted during the summer and harvested in the fall of 1992, 1993, and 1994. Vegetative growth from chickpeas was incorporated into the soil prior to wheat planting, and soil cores were taken at …

Comparison Of Ground-Based Remote Sensors For Evaluation Of Corn Biomass Affected By Nitrogen Stress, Soon-Dal Hong, James Schepers, Dennis D. Francis, Michael R. Schlemmer

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

The nondestructive determination of plant biomass is not possible; however, crop-canopy sensors that determine the normalized difference vegetation index have the potential to estimate living biomass, which is indicative of plant vigor and stress. Pot experiments using sand culture were conducted in 2002 and 2003 under greenhouse conditions to evaluate the effect of nitrogen (N) deficiency on corn biomass and reflectance. Stress was imposed by implementing six to eight levels of N in Hoagland’s nutrient solution. Canopy reflectance measurements made at three growth stages with a variety of handheld spectral sensors (active and passive) were closely correlated with dry weight …

Design And Testing Of A Closed, Stirring Respirometer For Measuring Oxygen Consumption Of Channel Catfish Eggs, Eugene L. Torrans

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

A closed, stirring respirometer was designed to agitate small egg mass samples of channel catfish Ictalurus punctatus while measuring oxygen consumption by the eggs. Egg mass samples ranging in size from 15 to 46 g were placed on a screen platform above a magnetic stir bar in the respirometer; the degree of agitation was controlled with a magnetic stir plate. Dissolved oxygen (DO) concentration and temperature were measured with a luminescent DO sensor and meter. The respirometer was used to determine routine metabolic rate and limiting oxygen concentration (the presumed hypometabolic transition zone) on egg mass samples from 10 different …

Techniques For Reclaiming Mined Lands With Native Plants, Maria Elena Melnechuk

Theses and Dissertations

In this experiment I examined the role of mycorrhizae, seeding rate, and fertilizer in promoting growth of native plants at a reclaimed mine site in central Arkansas. Permanent field plots were established to examine effects of treatments on native plant cover, nonnative plant cover, and bare ground. By the final year of data collection, 18 native species had been newly established at the experimental site. Compared to plots without mycorrhizae, plots with mycorrhizae had significantly higher native plant cover in the first sampling year only. The addition of native seed was important—plots without added seed had significantly lower native plant …

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 …

Tallgrass Prairie Center's Native Seed Production Manual, Gregory A. Houseal

Faculty Book Gallery

The intent of this manual is to provide basic information for native seed production of nearly 50 species of the tallgrass prairie flora of the upper Mid-west. The information presented is compiled from published accounts coupled with native seed production experience at the Tallgrass Prairie Center at the University of Northern Iowa. Critical to this effort were publications from the USDA-NRCS Plant Materials Program, published research articles and technical notes, and Internet resources. Botanical nomenclature follows USDA PLANTS Database (http://plants.usda.gov).

Floral Biology, Breeding System, And Pollination Ecology Of Cucurbita Moschata (Duch. Ex Lam) Duch. Ex Poir. Varieties (Cucurbitaceae) From Parts Of The Niger Delta, Nigeria, Ikechukwu Ozoemenam Agbagwa, Benjamin Chinyem Ndukwu, Stephen I. Mensah

Turkish Journal of Botany

Flowering, breeding mechanisms, and pollination biology of Cucurbita moschata (Duch. ex Lam) Duch. ex Poir. varieties were studied. C. moschata carries male and female flowers on the same plant and is pollinated by thrips and bees with nectar and pollen as major rewards for the pollinators. Both flowers begin opening between 0330 and 0400 hours. The male flower opens for about 8 to 9 h and the female opens for 6 h 30 min to 7 h. There is, however, a period of overlap in the flower anthesis of both sexes, which coincides with the peak of pollen viability and …

2007 Plant Community Survey Of The Wildcat Hills Banner & Scotts Bluff Counties, Nebraska, Robert F. Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

To facilitate conservation efforts within the BUL, vegetation surveys were conducted from July 5 to August 30, 2007 to provide additional information concerning the distribution and quality of native plant community and rare plant species occurrences within the area.

Approximately 50,000 acres were surveyed representing approximately one third of the Wildcat Hills west of Hubbard’s Gap Road. Landowners were contacted and permission to access their properties granted prior to field surveys. Nebraska Natural Heritage Program (NHHP) Ecological Community Survey Forms were completed to document plant communities, and NHHP Rare Plant Survey Forms were completed to document rare plants (S1 and …

C3–C4 Composition And Prior Carbon Dioxide Treatment Regulate The Response Of Grassland Carbon And Water Fluxes To Carbon Dioxide, H. W. Polley, W. A. Dugas, P. C. Mielnick, H. B. Johnson

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

During May, July and October 2000, we measured the effects of temporarily increasing or decreasing CO₂ concentration by 150–200 μmol mol⁻¹ on daytime net ecosystem CO₂ exchange (NEE) and water flux (evapotranspiration, ET) of C₃–C₄ grassland in central Texas, USA that had been exposed for three growing seasons to a CO₂ gradient from 200 to 560 μmol mol⁻¹. Grassland grown at subambient CO₂ (< 365 μmol mol⁻¹) was exposed for 2 days to an elevated CO₂ gradient (> 365 μmol mol⁻¹). Grassland grown at elevated CO₂ was …

Short-Term Response Of Soil Iron To Nitrate Addition, Christopher J. Matocha, Mark S. Coyne

Plant and Soil Sciences Faculty Publications

The inhibition of soil Fe(III) reduction by fertilizer NO3 − applications is complex and not completely understood. This inhibition is important to study because of the potential impact on soil physicochemical properties. We investigated the effect of adding NO3 − to a moderately well-drained agricultural soil (Sadler silt loam) under Fe(III)-reducing (anoxic) conditions. Stirred-batch experiments were conducted where NO3 − was added (0.05 and 1 mM) to anoxic slurries and changes in dissolved Fe(II) and Fe(III), oxalate-extractable Fe(II), and dissolved NO3 − were monitored as a function of time. Addition of 1 mM NO3 − inhibited Fe(II) production sharply with …

A Novel Endonuclease Activity Associated With The Arabidopsis Ortholog Of The 30-Kda Subunit Of Cleavage And Polyadenylation Specificity Factor, Balasubrahmanyam Addepalli, Arthur G. Hunt

Plant and Soil Sciences Faculty Publications

The polyadenylation of messenger RNAs is mediated by a multi-subunit complex that is conserved in eukaryotes. Among the most interesting of these proteins is the 30-kDa-subunit of the Cleavage and Polyadenylation Specificity Factor, or CPSF30. In this study, the Arabidopsis CPSF30 ortholog, AtCPSF30, is characterized. This protein possesses an unexpected endonucleolytic activity that is apparent as an ability to nick and degrade linear as well as circular single-stranded RNA. Endonucleolytic action by AtCPSF30 leaves RNA 3′ ends with hydroxyl groups, as they can be labeled by RNA ligase with [³²P]-cytidine-3′,5′-bisphosphate. Mutations in the first of the three CCCH …

Discovery: The Student Journal Of Dale Bumpers College Of Agricultural, Food And Life Sciences - Volume 8 2007, Several Authors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Multifunctional Rural Landscapes: Economic, Environmental, Policy, And Social Impacts Of Land Use Changes In Nebraska, Twyla M. Hansen, Charles A. Francis, J. Dixon Esseks, J. Allen Williams Jr.

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The conversion of farmland near cities to other human uses is a global trend that challenges our long-term capacity to provide food, fiber, and ecosystem services to a growing world population. If current trends continue in the United States, the population will reach 450 million by the year 2050. At the same time, an accelerating change in land use will reduce today’s two acres per person of farmland to less than one acre per person. This is scarcely enough to produce food for our domestic population, without any food available for export – even assuming advances in technology. We need …

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 …

Comparison Of Instrumental Methods For Measuring Seed Hardness Of Food-Grade Soybean, Mioko Tamura, Bo Zhang, Joyce Berger-Doyle, Pengyin Chen

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Seed hardness is an important factor in determining soybean suitability for natto production. There is no established methodology for testing seed texture of soybeans. The objective of this study was to develop an efficient method by examining different instruments and seed parameters that could be potentially used for testing soybean seed hardness. Five food-grade soybean genotypes with different seed sizes were used to determine seed hardness and water-absorption capacity. Water absorption capacity was expressed by swell ratios for seed weight, seed dimension, and volume of water changes before and after soaking. Seed hardness test was conducted by a one-bite method …

Mechanism Of Intraspecific Toxin Inhibition In Aspergillus Flavus, Changwei Huang

LSU Master's Theses

Atoxigenic Aspergillus flavus was demonstrated by others as a promising biocontrol agent to minimize preharvest aflatoxins in susceptible crops. But the mechanism was unclear. A filter insert-well plate system was used to study the mechanism in lab. There was no inhibition when toxigenic A. flavus isolate 53 and inhibitory atoxigenic isolates were separated by 0.4 µm membrane, approximately 50% inhibition occurred when separated by 12 µm membrane, and complete inhibition occurred when a 74 µm membrane was used. This result suggested that touching or close physical interaction is needed for toxin inhibition and the nutrient competition hypothesis was not supported. …

Succession Of An Iowa Sand Prairie Into An Adjoining Old-Field, Susan Jill Kirt

Dissertations and Theses @ UNI

Native plant succession studies were conducted in 2000 and 2001 at the Cedar Hills Sand Prairie northwest of Cedar Falls, IA. The study site consisted of a remnant sand prairie with an adjoining old-field that had been undergoing secondary succession since the mid-1970s. Vegetation was sampled over a 100 m transect of the remnant prairie and a 200 m transect of the old-field. The transect was sub-divided into 50 m subsites to examine progression of native species into the old-field. To analyze changes in vegetation, the similarity of the sub-sites were compared for percent canopy cover and number of species …

An Assessment Of The Risk Mapping System For The Use Of Managing Loblolly Pine Decline Sites Within Red-Cockaded Woodpecker Habitat, Roger Dale Menard

LSU Master's Theses

A decline of loblolly pine (Pinus taeda L.), characterized by expanding areas of declining and dead trees, has become prevalent at Fort Benning, Georgia. A 3 year study was conducted to determine the kinds of fungi, insects, and site disturbances associated with this problem. The insects Dendroctonus terebrans, Hylastes salebrosus, Hylastes tenuis, Pachylobius picivorus and Hylobius pales were significantly more abundant in symptomatic than in asymptomatic loblolly pine plots. These root and lower stem-infesting insects consistently carried the fungi Leptographium terebrantis, L. procerum, and L. serpens. Root sampling revealed high levels of root damage and mortality, staining and infection with …

Evaluation Of Three Tractor-Guidance Methods For Parallel Swathing At Two Field Speeds, Garris Hudson, Robby Shofner, George Wardlow, Donald Johnson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

This study compared the accuracy (mean error and rms error) and precision (standard deviation of error) of three tractor-guidance methods (foam-marker, light-bar, and assisted-steering systems) at two field speeds (5.6 – and 11.5 km/h) for parallel swathing operations. Eighty-four replications of each combination of guidance method and field speed were conducted between 15 October and 22 December 2006 (504 total field passes). The foam-marker system was found to be significantly less accurate [larger mean error (p < .0001) and had a larger rms error (p < .0001)] than either the light-bar or the assisted-steering system. There was no significant difference in mean error (p = .6718) or rms error (p = .8841) by field speed. There was a significant interaction between guidance method and field speed for both mean error (p = .0009) and rms error (p = .003). Mean and rms errors for the foam-marker and the assisted-steering systems increased at higher field speed, while the mean and rms errors for the light-bar system decreased at higher speed. The assisted-steering system had a significantly lower (p = .0164) standard deviation of error (higher precision) than the foam-marker or the light-bar systems. There was no significant difference in the standard deviation of error by field speed (p = .6258) or by the interaction of guidance method and field speed (p = .2748).

Landholder Information For The Safe Use And Management Of 1080, Renee Donovan, David Goodall

Biosecurity published reports

This manual outlines your roles and responsibilities for using and managing 1080. In particular this manual outlines the essential information you need to know in regard to:

• The legislative requirements for 1080 control in Western Australia
• The properties and mode of action of 1080
• How to lodge an application to lay 1080 baits How to safely store and transport 1080
• The procedures and notification required to carry out a baiting proposal
• Personal safety, identifying signs of poisoning & effecting appropriate first aid treatment
• Your responsibilities for notifying DAFWA and the Police of any accidents or incidents
• Methods for evaluating the …

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 …

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 …

The Influence Of Morningglory (Ipomoea Lacunosa), Hemp Sesbania (Sesbania Exaltata), And Johnsongrass (Sorghum Halepense) On Reproduction Of Rotylenchulus Reniformis On Cotton Gossypium Hirsutum L. And Soybean Glycine Max. (L.) Merrill, Michael John Pontif

LSU Doctoral Dissertations

Microplot studies were conducted to evaluate the effects of cotton (LA. 887), soybean (Pioneer 96B21), and three endemic weed species, pitted morningglory (Ipomoea lacunosa), hemp sesbania (Sesbania exaltata), and johnsongrass (Sorghum halepense), on reproduction of the reniform nematode, (Rotylenchulus reniformis). Over two microplot trials the co-culture of cotton with any of the three weeds suppressed numbers of reniform nematode juveniles in soil. When grown singly, reniform nematode reproductive values after 60 days on cotton averaged 69.0, while those for morningglory, hemp sesbania, and johnsongrass averaged 42.0, 23.5, and 18.0, respectively. Reproductive values for cotton co-cultured with morningglory averaged 38.7. Those …

Characterization Of Bacteriophages Of Pseudomonas Syringae Pv. Tomato, Sara E. Prior, Amanda J. Andrews, Russell O. Nordeen

Journal of the Arkansas Academy of Science

Bacteriophages from supernatants of the plant pathogenic bacteria Pseudomonas syringae pv. tomato (P. tomato) were isolated, enriched, and purified by density block centrifugation in cesium chloride (CsCl) step gradients. The DNA from purified phage was isolated and digested with the restriction endonucleases EcoRl or HindIII. Three different DNA fingerprint patterns were determined indicating 3 unique phage isolates. Genome sizes of the phage ranged from 40 to 52 kilobases (kB). Buoyant densities of phage particles in CsCI varied from 1.36 to 1.51 glml. Electron microscopy revealed a single morphological type with an elongated polyhedral head and a long tail indicating the …

Genetic Diversity And Low Reproductive Success In Isolated Populations Of Utah Juniper (Juniperus Osteosperma, Cupressaceae), Loreen Allphin, Val J. Anderson, Amy F. Hunt

Faculty Publications

Utah juniper (Juniperus osteosperma) has greatly expanded its historical range in the western United States. Management plans for the species have focused on curtailing its encroachment into sagebrush and grassland communities. These plans often include burning or other methods of elimination. These methods may result in subdivision or fragmentation of existing juniper stands. We initiated a study at Dugway Proving Ground, a U.S. Army facility, to examine the effects of fragmentation on the reproductive success of Utah juniper in isolated populations. We used enzyme electrophoresis to quantify genetic variability in isolated populations. We also determined population reproductive success by examining …

The Vascular Flora Of Saline County, Arkansas, Charles Theodore Witsell

Theses and Dissertations

The vascular flora of Saline County, Arkansas was collected from March 2002 to November 2007 resulting in a total of 1,510 taxa (52% of the known flora of Arkansas), representing 165 families, 617 genera, and 1,457 species. Of these, 241 (15.9%) are non-native and 99 (6.6%) are of state conservation concern. Of these, 20 taxa (1.3%) are considered to be of global conservation concern (G1-G3). Twenty-seven habitats and plant communities are qualitatively described from the county. Of these, shale barrens, igneous glades, pine flatwoods, swamp lakes and floatant marshes, channel scar depression ponds, high-gradient stream channels, and bluffs and talus …