Life Sciences Commons^™

Season And Genotype Influence Golf Ball Roll Distance On Creeping Bentgrass, A.M. Rist, Roch E. Gaussoin, Bob Shearman, J.D. Fry, Walter W. Stroup

Department of Agronomy and Horticulture: Faculty Publications

Golfers are demanding increased ball roll distances on a daily basis, but cultural practices to achieve this often are detrimental to the green. One option for increasing ball roll distance without altering cultural practices may be to select creeping bentgrass genotypes that provide less resistance to ball roll. Studies were conducted at the John Seaton Anderson Turfgrass and Ornamental Research Facility near Ithaca, Neb., and at the Rocky Ford Turfgrass Research Facility in Manhattan, Kans., to determine genotype and seasonal influences on golf ball roll distance. Eighteen creeping bentgrass (Agrostis palustris Huds.) genotypes were evaluated. Genotype was not a …

Mid-Career And Senior Faculty: Maintaining Vitality And Productivity, Daniel W. Wheeler

Department of Agronomy and Horticulture: Faculty Publications

Beginning in 1810 at Harvard Univ., mid-career and senior faculty were presented with opportunities for faculty renewal and development through sabbatical leaves. The focus was on increasing knowledge, skills, and research, particularly as a content expert. Faculty also attended their academic discipline annual meetings and conferences to increase content development.

Even with strong academic traditions and professional autonomy, some institutions began to provide expanded professional development activities, particularly to address teaching. However, the focus was often on seminars, with the major outcome to increase the subject matter expertise of the faculty.

Starting in the late 1950s, the academic and popular …

Molecular And Functional Characterization Of A Novel Low-Affinity Cation Transporter (Lct1) In Higher Plants, Daniel P. Schachtman, Raman Kumar, Julian I. Schroeder, Ellen L. Marsh

Department of Agronomy and Horticulture: Faculty Publications

The transport of cations across membranes in higher plants plays an essential role in many physiological processes including mineral nutrition, cell expansion, and the transduction of environmental signals. In higher plants the coordinated expression of transport mechanisms is essential for specialized cellular processes and for adaptation to variable environmental conditions. To understand the molecular basis of cation transport in plant roots, a Triticum aestivum cDNA library was used to complement a yeast mutant deficient in potassium (K⁺) uptake. Two genes were cloned that complemented the mutant: HKT1 and a novel cDNA described in this report encoding a cation …

Wind Protection And Planting Date Affect Snapbean Growth And Yield [Abstract], Mohammed Nazip Suratman, Laurie Hodges, James R. Brandle, Kenneth G. Hubbard

Department of Agronomy and Horticulture: Faculty Publications

The effects of windbreak shelter on growth, total, and marketable yield of snapbeans were evaluated during 1994 and 1995.

Impact Of Pesticide Residues In Composted Lawn Waste Compost On Vegetable Crops [Abstract], Cindy Stuefer-Powell, Patrick J. Shea, Laurie Hodges, Garald L. Horst

Department of Agronomy and Horticulture: Faculty Publications

To conserve space in the Lincoln (Nebraska) city landfill, a program for composting urban yard waste was initiated in 1992.

Windbreaks: An Important Component In A Plasticulture System, Laurie Hodges, James R. Brandle

Department of Agronomy and Horticulture: Faculty Publications

Windbreaks reduce wind speed and modify the microclimate in sheltered areas. Many producers use wind barriers in their production systems, but few producers recognize all of the benefits available or understand the principles involved in windbreak function and design. Wind has direct and indirect effects on plant growth and development. Direct effects include soil abrasion, increased transpiration, and lodging. Indirect effects are based on changes in the crop microclimate, which influence plant growth and yield. Windbreaks increase soil and air temperatures and can extend the growing season in sheltered areas, resulting in increased crop development, earlier crop maturity, and market …

Suppression Of Smooth Brome By Atrazine, Mowing, And Fire, Gary D. Willson, James L. Stubbendieck

Department of Agronomy and Horticulture: Faculty Publications

Burning and mowing were evaluated in 1989-1991 at Pipestone National Monument, Minnesota, as alternatives to atrazine to suppress smooth brome (Bromus inermis Leyss.) and to affect seeding success of big bluestem (Andropogon gerardii Vitman). Atrazine was the only treatment that significantly reduced smooth brome tiller density (-77% 1990; -70% 1991) as compared to unburned controls. Neither burning (-16% 1990; -37% 1991) nor mowing (-16% 1990; +10% 1991) resulted in significant reductions. Sod-seeded big bluestem failed in all treatments in both years. The failure of chemical and non-chemical management to affect sufficient smooth brome control for big bluestem seeding …

Immunofluorescent Localization Of Rubpcase In Degraded C4 Grass Tissue, M. S. Miller, Lowell E. Moser, Steven S. Waller, Terry J. Klopfenstein, B. H. Kirch

Department of Agronomy and Horticulture: Faculty Publications

Digestion-resistant tissues found in C4 grasses may allow soluble protein to escape rumen degradation. The objective of this study was to use immunofluorescent localization to follow loss of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCase) from switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) parenchyma bundle sheath cells (BSC) during rumen degradation. Fluorescent signal was observed from switchgrass and big bluestem BSC through 24 and 16 h in situ digestion, respectively, and from BSC associated with both intact tissue fragments, and isolated vascular bundles in omasal digesta and fecal material from steers (Bos tarus L.) grazing switchgrass. Immunofluorescent …

Applications Of An Ecophysiological Model For Irrigated Rice (Oryza Sativa)- Echinochloa Competition, John L. Lindquist, Martin Kropff

Department of Agronomy and Horticulture: Faculty Publications

A. simulation model of rice-barnyardgrass competition for light was used for two management applications. First simulations using47 weather data sets from four locations in Asia were conducted to evaluate the influence of weather variation on single year economic threshold densities of barnyardgrass. Second rapid leaf area expansion and leaf area index were evaluated as potential indicators of improved rice competitiveness and tolerance to barnyardgrass. Influence of weather variation on single year economic thresholds was small under the assumption that competition was for light only. Increasing early leaf area expansion rate reduced simulated barnyardgrass seed production and increased single year economic …

Analysis Of Aerial Photography For Nitrogen Stress Within Corn Fields, Tracy M. Blackmer, James S. Schepers, Gary E. Varvel, George Meyer

Department of Agronomy and Horticulture: Faculty Publications

Spatial variability of soil parameters within fields complicates N fertilizer recommendations for corn (Zea mays L.) production. Thus, the ability to identify differences in crop N status within corn fields could lead to efficiencies in N fertilizer application and decreased ground water pollution. In this study, we digitized aerial color photographic transparencies using an eight-bit scheme to generate digital counts for the red, green, and blue primary colors in the photographs at the R5 growth stage and related them to grain yield. Digital count responses were relative to the N treatment in which grain yield plateaued. Experiments were conducted …

Nitrogen Deficiency Detection Using Reflected Shortwave Radiation From Irrigated Corn Canopies, Tracy Blackmer, James S. Schepers, Gary E. Varvel, Elizabeth A. Walter-Shea

Department of Agronomy and Horticulture: Faculty Publications

Techniques that measure the N status of corn (Zea mays L.) can aid in management decisions that have economic and environmental implications. This study was conducted to identify reflected electromagnetic wavelengths most sensitive to detecting N deficiencies in a corn canopy with the possibility for use as a management tool. Reflected shortwave radiation was measured from an irrigated corn N response trial with four hybrids and five N rates at 0, 40, 80, 120, and 160 kg N ha^-1 in 1992 and 0, 50, 100, 150, and 200 kg N ha^-1 in 1993. A portable spectroradiometer was …

Potential For Controlling The Spread Of Centaurea Maculosa With Grass Competition, John L. Lindquist, Bruce D. Maxwell, T. Weaver

Department of Agronomy and Horticulture: Faculty Publications

ABSTRACT.-Spotted knapweed (Centaurea maculosa Lam.) is a major rangeland and roadside weed of the northern Rocky Mountains. It is often found in plant communities dominated by Pseudoroegneria spicatum or Festuca idahoensis, but it rarely invades roadsides dominated by Bromus inerrnis Leyss. Aboveground biomass of the 3 grass species grown in mixture with Centaurea was compared to growth in monoculture at a range of nitrogen input levels. The results suggest that Bromus is capable of suppressing the growth of Centaurea with the degree of suppression increasing with increasing nitrogen levels. The 2 native grasses had no impact on Centaurea …

Application Of The Single Kernel Wheat Characterization Technology To Sorghum Grain, Jeffrey F. Pedersen, C. R. Martin, F. C. Felker, J. L. Steele

Department of Agronomy and Horticulture: Faculty Publications

A single kernel wheat characterization system (SKWCS) was recently developed by the USDA, ARS Grain Marketing Research Laboratory and is currently being marketed by Perten Instruments North America, Inc. This device has been shown to accurately measure individual seed hardness, moisture, and size of wheat. The objective of this study was to determine if the SKWCS technology could be applied to the measurement of sorghum grain. Grains from 64 sorghum plots grown at Mead, NE in 1992 were characterized using a prototype SKWCS at the USDA, ARS Grain Marketing Research Laboratory. Problems encountered were primarily associated with the single kernel …

Annual Forages: New Approaches For C-4 Forages, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

The current agricultural paradigm in the U.S. is heavily biased towards the production and marketing of crops as commodities. This paradigm is kept in place by grain handling and marketing infrastructure, as well as government farm programs, designed for crops as commodities. Sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) grown for grain certainly fit into this current paradigm.

A new approach to agricultural production and marketing, identity preserved products, is gaining in importance. This is made possible through new technologies and markets demanding products designed specifically for their needs. Examples of investment in identity preserved …

Media Effects On Phenotype Of Callus Cultures Initiated From Photoperiod-Insensitive, Elite Inbred Sorghum Lines, H. F. Kaeppler, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Sorghum (Sorghum bicolor L. Moench) is a crop of worldwide agronomic importance. Routine production of high quality (friable, embryogenic, fast growing) callus cultures is fundamental to tissue culture based genetic study and improvement of sorghum. Genotype by culture medium interactions for sorghum callus growth and morphology have been previously reported. The objective of this study was to identify tissue culture media that would support high quality callus growth across photoperiod insensitive, relatively elite genotypes. Explants from immature inflorescences of 11 sorghum genotypes were cultured on 6 tissue culture media of differing composition. After 3 and 5 months in culture, calli …

Germplasm And Cultivar Development, M. D. Casler, Jeffrey F. Pedersen, G. C. Eizenga, S. D. Stratton

Department of Agronomy and Horticulture: Faculty Publications

Cool-season forage grasses have evolved, and continue to evolve, in natural ecosystems subject to environmental factors both in the presence and absence of human influences. The literature often lacks facts describing the evolution and domestication of forage grasses. Furthermore, the literature on this subject mainly deals with evolution of species in the broad scope, i.e., on a scale of hundreds of thousands or millions or years. Thus, some of our conclusions are necessarily speculative and are highly subject to the nature of the research that has been reported. We describe the forces of selection that act upon cool-season forage grasses …

Breeding Sorghum And Pearl Millet For Forage And Fuel, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Sorghum [Sorghum bicolor (L.) Moench] and pearl millet [Pennisetum glaucum (L.) R. Br.] are unique species in their ability to be used in many forage llivestock system roles. Such flexibility has made prioritizing breeding objectives difficult and has even contributed to contradictory opinions on appropriate forage breeding objectives. Few breeding projects identified in the USDA-ARS, USDA-CREES, or at ICRISAT had forage sorghum or forage pearl millet as their sole research assignment. In the United States, it can be argued that breeding resources committed to forage sorghum improvement are probably declining. A new forage sorghum and forage pearl millet …

Adaptability And Reliability Of Yield For Four Bell Pepper Cultivars Across Three Southeastern States, Laurie Hodges, Douglas C. Sanders, Katharine B. Perry, Kent M. Eskridge, K. M. (Dean) Batal, Darbie M. Granberry, Wayne J. Mclaurin, Dennis Decoteau, Robert J. Dufault, J. Thomas Garrett, Russell Nagata

Department of Agronomy and Horticulture: Faculty Publications

Four bell pepper (Capsicum annuum L.) cultivars were evaluated for yield (total weight of marketable fruit) performance over 41 environments as combinations of 3 years, three planting dates, and seven locations across North Carolina, South Carolina, and Georgia. Cultural practices, including trickle irrigation and double rows planted on black plastic-covered beds, were uniform across all environments, except for fertilization, which was adjusted at each location based on soil tests. Comparing production over 3 years between the mountain location and the Coastal Plain location in North Carolina, yields were lower on the Coastal Plain. Spring plantings provided higher yields than …

Weed Suppression With Grazing Or Atrazine During Big Bluestem Establishment, B. Keith Lawrence, Steven S. Waller, Lowell E. Moser, Bruce Anderson, Larry L. Larson

Department of Agronomy and Horticulture: Faculty Publications

Weed competition is a major factor causing warm-season grass seeding failures in rangeland and cropland. With a limited number of herbicides available for weed control, grazing may reduce competing vegetation in seedings and serve as an alternative to herbicides. Many immature needy forbs and grasses are palatable to cattle and contain high nutrient levels. Research was conducted (RCBD, 4 reps) comparing grazing by yearling cattle with chemical suppression [atrazine (6-chloro-N-ethyl-N’- (methylethyl)-1, 3, 5-triazine-2, 4-diamine)] for weed control in big bluestem (Andropogon gerardii var. gerardii Vitman) seedlings at Mead, Nebr. on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic …

Ruminal Degradation Of Switchgrass, Big Bluestem, And Smooth Bromegrass Leaf Proteins, Daren D. Redfearn, Lowell E. Moser, Steven S. Waller, Terry J. Klopfenstein

Department of Agronomy and Horticulture: Faculty Publications

Two in situ protein disappearance experiments were conducted to determine disappearance rates of leaf protein fractions and characterize individual leaf protein fractions that escaped ruminal degradation. Fresh leaf blades of two warm-season grasses, switchgrass (Panicum uirgatum L. 1 and big bluestem (Andropogon gerardii Vitman), and one cool-season grass, smooth bromegrass (Bromus inermis Leyss.), were included in Exp. 1. Only warm season grasses were used in Exp. 2. Leaves were harvested from greenhouse-grown plants, placed in polyester bags, and incubated up to 48 h in situ in three ruminally fistulated steers fed diets of warm season grass hay. …

Quantifying Developmental Morphology Of Perennial Grasses, K. J. Moore, Lowell E. Moser

Department of Agronomy and Horticulture: Faculty Publications

Perennial forage grasses can be viewed as modular organisms. The phytomer is usually considered the basic unit of the grass plant and consists of a leaf blade and sheath, the internode, the node, and the associated axillary bud below the point of sheath attachment. The tiller is a collection of phytomers differentiated from a single apical meristem. The grass plant is a group of tillers that ultimately arise from a single zygote and are of the same genotype. A grass sward is a population of individual plants, often genetically related, but usually of unique genotypes. The developmental morphology of perennial …

Modeling The Population Dynamics And Economics Of Velvet Leaf (Abutilon Theophrasti) Control In A Corn (Zea Mays)-Soybean (Glycine Max) Rotation, John L. Lindquist, Bruce D. Maxwell, Douglas D. Buhler, Jeffrey L. Gunsolus

Department of Agronomy and Horticulture: Faculty Publications

A simulation model was developed to predict the population dynamics and economics of velvetleaf control in a corn-soy bean rotation. Data compiled from the literature were used to parameterize the model f or two situations, one in which velvetleaf was infected by a Verticillium spp. wilt and one without infection. Verticillium was assumed to have no effect on corn or soybean yield. In the absence of control, simulated seed bank densities of a Verticillium-infected velvetleaf population were 5 to 50 times lower than for an uninfected velvetleaf population. The model was used to evaluate a threshold weed management strategy …

Statistical Analysis Of Disease Reaction Data Using Nonparametric Methods, Kent M. Eskridge

Department of Agronomy and Horticulture: Faculty Publications

Plant breeders developing disease-resistant horticultural crops need flexible and powerful statistical methods to compare treatments efficiently. The most commonly used statistical methods are those based on analysis of variance (ANOVA), regression, and correlation. The valid use of these methods requires that the data have 1) normally distributed responses, 2) constant error variance, 3) independently distributed errors, and 4) a correctly specified model. However, many plant disease experiments yield data that do not adhere to these standard assumptions. For example, in an experiment involving population levels of a pathogen, rarely will population levels be normally distributed. Field counts of the number …

Trees On The Great Plains: Agro-Ecosystem Diversity, Laurie Hodges, Mary Ellen Dix, James R. Brandle, Mark O. Harrell, Robert J. Wright, Ron J. Johnson, Ronald M. Case, Kenneth G. Hubbard, Linda J. Young, Rebecca L. Fitzmaurice, Nathalie J. Sunderman, Michele M. Schoeneberger

Department of Agronomy and Horticulture: Faculty Publications

Agriculture in the Great Plains faces increasing pressure for environmental stewardship and for more economical farming and pest management practices. The concept of sustainable agriculture was developed to address these needs. A sustainable agricultural system is one that consistently enhances environmental quality and the resource bases, provides basic human food and fiber needs, is economically viable, and enhances the quality of life for farmers and society. In the Great Plains, we define agroforestry as the use of trees to help make agricultural production systems more sustainable. The trees function to conserve soil, water, wildlife, and other natural resources. They also …

Influences Of Trees On Abundance Of Natural Enemies Of Insect Pests: A Review, Mary Ellen Dix, R. J. Johnson, Mark O. Harrell, Ronald M. Case, Robert J. Wright, Laurie Hodges, James R. Brandle, Michelle M. Schoeneberger, N. J. Sunderman, R. L. Fitzmaurice, Linda J. Young, Kenneth G. Hubbard

Department of Agronomy and Horticulture: Faculty Publications

In this article we review the use of natural enemies in crop pest management and describe research needed to better meet information needs for practical applications. Endemic natural enemies (predators and parasites) offer a potential but understudied approach to controlling insect pests in agricultural systems. With the current high interest in environmental stewardship, such an approach has special appeal as a method to reduce the need for pesticides while maintaining agricultural profitability. Habitat for sustaining populations of natural enemies occurs primarily at field edges where crops and edge vegetation meet. Conservation and enhancement of natural enemies might include manipulation of …

In Vitro Starch Disappearance Procedure Modifications, C. J. Richards, Jeffrey F. Pedersen, R. A. Britton, R. A. Stock, C. R. Krehbiel

Department of Agronomy and Horticulture: Faculty Publications

Four in vitro experiments evaluated the effects of ruminal fluid inoculum:artificial saliva ratios,

grinder type, grind size, and diet of ruminal fluid donor on in vitro starch disappearance. Experiment 1 examined rates of starch disappearance and coefficients of determination obtained by linear regression of starch disappearance using five grain sorghum (Sorghum bicolur (L.) Moench) lines, a corn (Zeu muys L.) control, and a wheat (Triticum aestivum L.) control. Grains were incubated for 4, 8, 12, 16, and 20 h with inoculum varying in proportion of ruminal fluid and artificial saliva ( l:l, 1:2, 1:3, and 1:4). In …

An Automated Plot Harvest System For Use With A Commercial Forage Harvester, Jeffrey F. Pedersen, Kenneth J. Moore

Department of Agronomy and Horticulture: Faculty Publications

This automated harvest system is based on minimal modification of currently available commercial forage harvesters. Using 6.8 m plots separated by 0.75 m alleys, a single operator can harvest, finely chop, and collect wet plot weights of forage sorghum [Sorghum bicolor (L.) Moench] or pearl millet [Pennisetum glaucum (L.) R. Hr.] in <1 min per plot. Harvested material is deposited in a pile in the center of each plot. Subsamples for moisture and quality analysis can easily and safely be obtained from the pile.

Classical And Molecular Approaches To Breeding Horticultural Plants For Disease Resistance: Introduction To The Colloquium, Dermot P. Coyne

Department of Agronomy and Horticulture: Faculty Publications

Diseases of horticultural crops have always been a concern of crop producers, processors, merchandisers, and consumers because of reductions in yield and product quality. Excessive chemical application to control diseases of some crops has been a health concern in some countries. Some diseases pose a major constraint, or even a threat, to the production of a crop in a region. Plant breeders, in association with plant pathologists, have had notable successes in breeding disease-resistant varieties, thus ensuring the economic production of a crop. There is now an increased need to breed for disease resistance of horticultural crops because of a …

‘Lakota’ Winter Squash, A Cultivar Derived From Native American Sources In Nebraska, Dermot P. Coyne, J.M. Reiser, Lisa Sutton, Alice Graham

Department of Agronomy and Horticulture: Faculty Publications

‘Lakota’ is a novel, smooth- and thinskinned, small-fruited, early maturing, ovoidshaped winter squash [Cucurbita maxima (Duch.)] (Fig.1). Plants produce fruit exhibiting various degrees of green and orange variegated patterns, along with some solid green and orange fruit. ‘Lakota’ was released because of its novel decorative value and good baking quality. A similar winter squash is not available commercially.

Origin

Seeds of the winter squash population from which ‘Lakota’ was selected were donated to the Univ. of Nebraska, Lincoln, by A.G., who originally received the seed from the late Martha Newman, Alliance, Neb. By examining the Quarter Master Reports (1820), …

A Modified Stimpmeter For Small-Plot Turfgrass Research, Roch E. Gaussoin, Jeff Nus, Larry Leuthold

Department of Agronomy and Horticulture: Faculty Publications

Golf ball roll is measured with a United States Golf Association (USGA) Stimpmeter. Three Stimpmeters were fabricated identically to the USGA Stimpmeter, except for the location of the ball release notch. The modified Stimpmeters had ball release notches located at 57, 38, and 19 cm, rather than at 76 cm from the beveled end. The modified Stimpmeters were tested on a creeping bentgrass green located at Mead, Neb., at three mowing heights (4.8, 4.0, and 3.2 mm). The Stimpmeters were effective in measuring golf ball roll distance and provided reasonable and consistent estimates of friction. Modified Stimpmeters are relatively inexpensive …