Life Sciences Commons^™

Influence Of Developmental Stage Of Melilotus Infesta Leaves On Resistance To Feeding By The Sweetclover Weevil, W. R. Akeson, G. L. Beland, Francis A. Haskins, H. J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Leaves of 6- to 8•week old Melilotus infesta plants contained progressively higher levels of nitrate as the leaves developed from the tightly pinched to the fully expanded stage. In weevil feeding tests on water extracts of these leaves a close relationship was found between actual feeding and the feeding predicted on the basis of nitrate content. At a given level of nitrate, extracts of young M. infesta leaves were less attractive to the weevil than were extracts of young M. officinalis leaves. Leaves of mature M. infesta plants contained very little nitrate, but water extracts of such leaves remained unattractive …

Genetic Studies Of Induced Mutants In Melilotus Alba. I. Short-Internode Dwarf, Curled Leaf, Multifoliolate Leaf, And Cotyledonary Branching, B. G. Gengenbach, Francis A. Haskins, H. J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

Information obtained from the F₁, F₂, and F₃ generations of crosses between the normal annual M. alba progenitor line and the four mutants, short-internode dwarf, curled leaf, multifoliolate leaf, and cotyledonary branching, indicates that each character is conditioned by a single pair of alleles. The multifoliolate leaf character is dominant over the normal phenotype; the other three mutant characters are recessive. The symbols dw, cl, Mf, and cb are proposed as designations for the respective mutant genes.

Animal Performance On Crested Wheatgrass Pastures During May And June, Fort Rock, Oregon, D. W. Hedrick, W. M. Moser, A. L. Steninger, R. A. Long

Department of Agronomy and Horticulture: Faculty Publications

Average animal performance data of 1.5 lb/animal daily gain, two calendar months of grazing, and 20 lb/acre gain were obtained from 5 years of using crested wheatgrass under a 2-crop (May) and 1-crop (June) system of grazing. Regrowth was obtained on early use (2-crop) pastures in only 2-out of the 5 years. Extension of results to users was hastened by involving ranchers, a county agent, and a federal agency manager in the study.

Contamination In Denta Sweetclover During Successive Generations Of Seed Increase, H. J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

Contamination levels observed in the breeder, foundation, and certified seed generations of 'Denta' sweetdover (Melilotus alba Desr.) were 0.71, 1.69, and 3.62%, respectively, as measured by the frequency of plants high in content of o-hydroxycinnamic acid. Based on a sample of plants tested simultaneously for o-hydroxycinnamic acid content and ,β-glucosidase activity, a small but consistent decrease in the frequency of cu plants occurred with succeeding seed generations, while shifts in the frequency of b plants were not consistent in magnitude or direction. Contamination through cross-pollination with CuCuBB plants may be the major factor responsible for the observed decreases in …

Absence Of Dominance Of The Cu Gene In Influencing O-Hydroxycinnamic Acid Content In Melilotus Alba, Francis A. Haskins, H. J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

The average content of o-hydroxycinnamic acid in sweetclover plants of the Cucu genotype was 36% of the level found in CuCu plants. Thus, the level of o-hydroxycinnamic acid in the F₂ was more like the content of the cucu parent than that of the Cucu parent, indicating that cu was partially dominant over Cu. The calculated value for the degree of dominance of cu over Cu was +0.299. The partial dominance of the cu gene provides an explanation for the difficulty experienced in classifying plants in segregating populations.

Sweetclover-Weevil Feeding Deterrent B: Isolation And Identification, W. R. Akeson, H.J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

Deterrent B, a compound apparently involved in the resistance of Melilotus infesta to the sweetclover weevil Sitona cylindricollis, has been isolated from leaves by a combination of preparative paper chromatography, sublimation, and crystallization. The compound has been identified as ammonium nitrate. Isolated deterrent B and ammonium nitrate have identical feeding deterrent activities. Although the deterrent principle was isolated as the ammonium salt, nitrate ion is probably responsible for the deterrent activity in vivo.

Engineering For Higher Yields, Yoshiaki Ishizuka

Department of Agronomy and Horticulture: Faculty Publications

It was difficult for me to understand the meaning of "engineering" as used in the title of my speech. I asked Dr. Haskins who told me that the term engineering is used here because one traditional role of the engineer has been the application of scientific principles in the solution of practical problems, and that in this case we want to consider the application of biological principles in both past and future increases in crop yield. Accordingly, I intend to express my thoughts on this problem, and to ask your suggestions for obtaining higher and better yields in the future. …

Mechanisms Of Translocation Of Plant Metabolites, Orlin Biddulph

Department of Agronomy and Horticulture: Faculty Publications

The mechanism of translocation has been discussed since the latter part of the 19th Century, when DeVries, in 1885, proposed protoplasmic streaming as the mechanism. Since that time O. F. Curtis, beginning about 1920, and more recently Thaine (1961) and Canny and Phillips (1963) have become interested in this approach to the problem. In the meantime Munch, in 1930, proposed a pressure flow mechanism based on a turgor pressure gradient in the phloem between metabolite supplying and metabolite consuming areas. These two mechanisms, and others, are fully discussed in Swanson (1959), so the present paper will deal with a compilation …

Metabolic Sinks, Harry Beevers

Department of Agronomy and Horticulture: Faculty Publications

The continued growth of higher green plants well supplied with water and inorganic nutrients depends primarily on (i) the accomplishment of photosynthesis in the leaves and (ii) the transport of organic compounds from the leaves to heterotrophic cells which constitute metabolic sinks.

Productivity And The Morphology Of Crop Stands: Patterns With Leaves, R. S. Loomis, W. A. Williams

Department of Agronomy and Horticulture: Faculty Publications

The primary productivity of communities made up of autotrophic green plants I initially dependent upon photosynthesis. The patterns of chlorophyll display at each level of community organization revel features which can be related to light interception and photosynthetic activity, and hence, to production. Studies on the comparative morphology of such displays should reveal principles useful for designing more efficient crops. It is important that we identify these principles since existing patterns are not necessarily the most efficient for intensive agriculture – a consequence of natural selection, even under a strong influence of man, having occurred principally in poverty environments and …

Physiological Significance Of Internal Water Relations To Crop Yield, R. O. Slatyer

Department of Agronomy and Horticulture: Faculty Publications

The overall effects of water deficits on crop yield are known to everybody. Moderate water deficiencies can result in stunting, distorted development, and much reduced crop yields, and prolonged drought can cause complete crop failure.
Despite these visible symptoms of deficiency, a clear and unambiguous statement as to the effect of deficits on crop yield is difficult to make, for a variety of reasons. Firstly, despite the importance of the phenomenon to agriculture in most of the food producing countries of the world, relatively little attention has been devoted to its water deficits. Secondly, and in part this is a …

Systems Analysis Of Natural Resources And Crop Production, Marion Clawson

Department of Agronomy and Horticulture: Faculty Publications

Human history is a seamless web; every event has its antecedents, its contemporaries, and its consequences. Each event arises out of the past, each is associated with other events at the time, and each leads to new events, in an endless chain. Indeed, there is difficulty in isolating any single event; when did it begin, what are its boundaries, when did it end? These are some of the problems of the social scientist generally, and of the historian in particular.
Nature is equally a seamless web. Every natural process or event has its cause or antecedent, each takes place within …

Gaseous Exchange In Crop Stands, Edgar Lemon

Department of Agronomy and Horticulture: Faculty Publications

Man through the ages has evolved a strategy, albeit empirical, of manipulating the environment and the plant to his advantage. Practices such as fertilizing the soil, irrigation, weed control, and plant breeding and selection are common. Nonetheless, concentrated and coordinated efforts to understand the mechanisms controlling the whole soil-plant- atmosphere continuum is a new approach to finding new ways to favorably manipulate the whole system as well as predict response.
Conceptually and experimentally it has proven advantageous to view the total system in terms of energy, momentum, and mass exchange. This makes sense because in the first instance the foundations …

Light Interception And Radiative Exchange In Crop Stands, John Monteith

Department of Agronomy and Horticulture: Faculty Publications

Crops grow and use water because they intercept radiation from the sun, the .sky, and the atmosphere. Diurnal changes of solar radiation dictate the diurnal course of photosynthesis and transpiration, and the vertical gradient of radiant flux in a canopy is a measure of the absorption of energy by foliage at different heights. Without exaggeration, the distribution of radiation within a plant community is the most important single element of microclimate.
Early ecological studies of radiation climate were mainly descriptive and were limited in scope by rather primitive instrumentation. A new quantitative approach to the subject was initiated by Monsi …

Subject Index For Physiological Aspects Of Crop Yield

Department of Agronomy and Horticulture: Faculty Publications

Subject Index
8 pages
Anatomy [to] Yield, requirement

Physiological Aspects Of Crop Yield (Frontmatter), Jerry D. Easton, Francis A. Haskins, C. Y. Sullivan, C. H. M. Van Bavel

Department of Agronomy and Horticulture: Faculty Publications

Foreword
Preface
Contributors
Contents

This volume is the outgrowth of an international symposium held at Lincoln, Nebraska, January 20-24, 1969. It was sponsored by the University of Nebraska in cooperation with the American Society of Agronomy and the Crop Science Society of America with partial financing by the Rockefeller Foundation and the International Biological Program.
The symposium planning committee was broadly based and was able to bring specialists from many parts of the world to the conference. Thus, the technical presentations were drawn from outstanding authorities backed up by a clear perspective of social needs. This was a happy combination …

Germ Plasm Manipulations Of The Future, George Sprague

Department of Agronomy and Horticulture: Faculty Publications

The topic, Germ Plasm Manipulations of the Future, could cover the entire field of genetics. This would be a very difficult assignment and, were I willing to attempt it, one that might not best serve the specific purpose of this symposium. I shall take a much more restrictive view and consider only certain phases of genetics which, in my opinion, will become of increasing importance in crop improvement.
In the period since 1900 genetics has achieved close and reciprocally productive relations with several fields of science. A partial listing of these would include genetics and cytology to yield cytogenetics; genetics …

Environmental Manipulation For Higher Yields, Paul Waggoner

Department of Agronomy and Horticulture: Faculty Publications

My role in this chapter on environmental manipulations is making a prediction that can be used until experiments render the final verdict.
In chapters preceding mine, an array of physical and physiological phenomena for affecting yield has been laid before the grower of plants. Predicting whether environmental manipulation will increase yield requires that all of these phenomena be considered for foreign lands are littered with the bleaching bones of immigrant varieties and practices that were ambushed by an unsuspected environmental difference.
Interaction is the Scylla of biologic prediction. Formerly we predicted by drawing a curve or writing a formula relating …

Cultural Manipulation For Higher Yields, William Duncan

Department of Agronomy and Horticulture: Faculty Publications

By cultural manipulation we will mean, in a broad sense, everything a farmer might do to increase crop yields per hectare, after he decides what to plant and buys the seed. With this restriction we leave out the agricultural economist and the plant breeder. When we limit our interest to yields per hectare we introduce an element of area. This will include the crop canopy above the surface and the root system below it. Cultural manipulation also includes what the farmer might do to make best use of water, carbon dioxide, nitrogen, and essential mineral nutrients whether they occur naturally …

Development, Differentiation, And Yield, John Heslop-Harrison

Department of Agronomy and Horticulture: Faculty Publications

The task of reviewing some of the ways development and differentiation may act as determinants of economic yield would be much simpler had knowledge advanced to a point where the basic principles concerned in the control of these processes in eukaryotic organisms were clear. Unfortunately, this stage has not yet been reached. There is no shortage of schemes and hypotheses to set beside a mountain of observational and experimental data, but the unifying thread which might allow us to pick out the significant and reject the irrelevant in any particular context is still lacking. What is incontestable is that development …

Plant Morphology And Stand Geometry In Relation To Nitrogen, Robert F. Chandler Jr.

Department of Agronomy and Horticulture: Faculty Publications

During the past decade, the importance of plant morphology and spacing in relation to nitrogen responsiveness in terms of crop yield has been increasingly recognized, particularly in the case of the cereal grains.
It is the purpose of this paper to present examples of experimental results obtained by rice research workers which support certain significant principles. Although this treatise will be confined to the rice plant (Oryza sativa L.),as Wittwer (1968) points out, the principles elucidated are applicable to many other crops, and particularly to the small grains, such as wheat (Triticum aestivum L.), oats (Avena sativa …

Physiological Responses To Nitrogen In Plants, Yoshio Murata

Department of Agronomy and Horticulture: Faculty Publications

Recent advances in crop physiology have given us some clues for analysis of the complex relationships of environmental factors, cultural conditions and genetic factors to crop yield. However, in order to accomplish this analysis, it is quite necessary to have concrete knowledge about the causal relationships and the time sequence of the processes of yield-formation.
In grain crops, the process of yield-formation may be divided into the following three phases:
1) Formation of organs for nutrient absorption and photosynthesis,
2) Formation of flower organs and "yield-container," and
3) Production, accumulation and translocation of "yield-contents."
The effect of nitrogen, which has …

Mechanisms Of Carbon Fixation And Associated Physiological Responses, Israel Zelitch

Department of Agronomy and Horticulture: Faculty Publications

Recent work in this laboratory has been directed towards increasing net photosynthesis or decreasing the transpiration rate in higher plants by exercising biochemical control over these processes. In these experiments, the fact that both photosynthesis and transpiration involve diffusion processes that might be regulated by varying appropriate diffusive resistances has been exploited (Gaastra, 1959; Zelitch and Waggoner, 1962a). Since in most instances the pathway of diffusion of water vapor in transpiration is shorter than that of CO2 uptake in photosynthesis, and both gases must pass through the stomata, it was predicted that closing the stomata in a specific manner would …

Interrelationships Among Photosynthesis, Respiration, And Movement Of Carbon In Developing Crops, Volkmar Stoy

Department of Agronomy and Horticulture: Faculty Publications

From the preceding lectures we have learned a great deal about how external conditions may influence various internal physiological processes within plants, and it therefore appears appropriate to consider briefly how these processes influence one another and also the manner in which they relate to yield. The main processes of interest in this connection are photosynthesis, respiration, and carbon assimilate translocation; but aspects of growth, development, mineral nutrition, etc., will also be considered when relevant.

Rollins Adams Emerson (1873-1947) Horticulturist Pioneer Plant Geneticist Administrator Inspiring Student Adviser, Rosalind Morris

Department of Agronomy and Horticulture: Faculty Publications

The vigorous and highly productive life of Professor R. A. Emerson spanned 74 years and 7 months. His birth and death took place In New York State, but Nebraska nurtured his early development and schooling. He spent 15 years of his professional career at the University of Nebraska, followed by 33 years at Cornell University.

Rollins Adams Emerson, son of Charles David and Mary C. Adams Emerson (a direct descendant of Henry Adams), was born May 5, 1873 at Pillar Point, New York State on the eastern shore of Lake Ontario. In 1880 his family moved to Nebraska and settled …

Rhizome And Tiller Development Of Kentucky Bluegrass (Poa Pratensis L.) As Influenced By Photoperiod, Cold Treatment, And Variety, Lowell E. Moser, S. R. Anderson, R. W. Miller

Department of Agronomy and Horticulture: Faculty Publications

Two controlled environment experiments were designed to study the effect of photoperiod and a cold treatment on rhizome and tiller development of ‘Merion’ and ‘Windsor’ Kentucky bluegrass (Poa pratensis L.) Evidence is given to support the following conclusions:

1. A cold treatment is not essential for rhizome formation. Cold treatments increased tillering but reduced the number of rhizomes.
2. Both initiation and elongation of rhizomes were favored by a 16 or 18-hour photoperiod when compared to a 8- or 12- hour photoperiod.
3. Tillering showed little response to initial photoperiod, although more tillers were formed with a 12-hour than …

Mutation Induction In Melilotus Alba Annua By Chemical Mutagens, A. Kleinhofs, Herman J. Gorz, Francis A. Haskins

Department of Agronomy and Horticulture: Faculty Publications

Hydroxylamine (HA), 2-aminopurine (AP), 5-bromouracil (BU), and ethyl methanesulfonate (EMS) were tested for mutagenic activity on seeds of Melilotus alba annua. Mutants were classified into the following categories: o-hydroxycinnamic acid (o-HCA) content and β-glucosidase activity, chlorophyll deficiency, dwarf growth habit, and miscellaneous morphological variations. Due to difficulties in classification, the o-HCA and β-glucosidase category and the dwarf category were unreliable for determining mutation rates. Based on the chlorophyll-deficient and miscellaneous morphological categories, mutation rates for HA, AP, and BU treatments did not differ from the control rates, but EMS at 0.003M and 0.004M …

Water-Soluble Factors In Melilotus Leaves Which Influence Feeding By The Sweetclover Weevil, W. R. Akeson, Francis A. Haskins, Herman J. Gorz, G. R. Manglitz

Department of Agronomy and Horticulture: Faculty Publications

One factor which stimulates feeding and two factors which deter feeding by the adult sweetclover weevil have been separated by preparative paper chromatography of hot water extracts of Melilotus leaves. The factors were detected with a bioassay which measures feeding by adult weevils on sweetclover root disks impregnated with the extract or fraction being tested. A feeding stimulant (Stimulant A) and a feeding deterrent (Deterrent A) were found in both the resistant species, M. infesta, and a susceptible species, M. officinalis, in approximately equal amounts. A second feeding deterrent (Deterrent B) was found only in extracts from M. …

A Water-Soluble Factor In Melilotus Officinalis Leaves Which Stimulates Feeding By The Adult Sweetclover Weevil, W. R. Akeson, Herman J. Gorz, Francis A. Haskins, G. R. Manglitz

Department of Agronomy and Horticulture: Faculty Publications

Akeson et al. (1967) reported that the water-methanol phase of a water-methanol-chloroform extract, obtained from leaves of Melilotus officinalis L. Lam. (variety Goldtop), stimulated extensive feeding by the sweetclover weevil, Sitona cylindricollis (Fähreus), on bioassay disks prepared from sweetclover roots. Subsequent studies have shown that a hot-water extract will elicit a similar response. When disks were treated only with the solvent used in extraction, an almost negligible amount of feeding was obtained. Thus, leaves of Goldtop sweetclover apparently contain one or more water-soluble feeding stimulants. Beck (1965) defined a feeding stimulant as a a stimulus tending to promote continuous feeding. …

Trans-O-Hydroxycinnamic Acid Glucosylation In Cell-Free Extracts Of Melilotus Alba, A. Kleinhofs, Francis A. Haskins, Herman J. Gorz

Department of Agronomy and Horticulture: Faculty Publications

The glucosylation of trans-o-hydroxycinnamic acid has been demonstrated in cell-free extracts of MeliIotus alba. The reaction requires UDPG, a sulfhydryl compound, and an active extract from sweet clover leaves. The product of the reaction has been tentatively identified as trans-β-D-glucosyl-o-hydroxycinnamic acid.