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Articles 25501 - 25530 of 26271
Full-Text Articles in Entire DC Network
Physiological Aspects Of Crop Yield (Frontmatter), Jerry D. Easton, Francis A. Haskins, C. Y. Sullivan, C. H. M. Van Bavel
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
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
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
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
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.
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 …
Rollins Adams Emerson (1873-1947) Horticulturist Pioneer Plant Geneticist Administrator Inspiring Student Adviser, Rosalind Morris
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 …
Systems Analysis Of Natural Resources And Crop Production, Marion Clawson
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 …
Successional Patterns In Diverted Croplands Of Crawford County, Illinois, Norman Tracy
Successional Patterns In Diverted Croplands Of Crawford County, Illinois, Norman Tracy
Masters Theses
No abstract provided.
The Prairie Naturalist Volume 1, No.4. December 1969
The Prairie Naturalist Volume 1, No.4. December 1969
The Prairie Naturalist
EDITORIAL: Restoring Beauty to the Human Environment ▪ Paul B. Kannowski
A REQUIEM FOR THE PRAIRIE ▪ Hugh H. Iltis
BIRDING IN MY BACK YARD ▪ Mrs. George A. Anderson
OCCURRENCE OF THE CECROPIA AND ROCKY MOUNTAIN SILK MOTHS IN SOUTHWESTERN NORTH DAKOTA ▪ James Oberfoell
Protein Synthesis During Fungal Spore Germination Ii. Aminoacyl-Soluble Ribonucleic Acid Synthetase Activities During Germination Of Botryodiplodia Theobromae Spores, James L. Van Etten, Robert Brambl
Protein Synthesis During Fungal Spore Germination Ii. Aminoacyl-Soluble Ribonucleic Acid Synthetase Activities During Germination Of Botryodiplodia Theobromae Spores, James L. Van Etten, Robert Brambl
Department of Plant Pathology: Faculty Publications
The specific activities of 13 aminoacyl-soluble ribonucleic acid (sRNA) synthetases were measured at various time intervals during the germination of Botryodiplodia theobromae conidiospores. The enzyme activities were low or absent in ungerminated spores, and they increased rapidly as germination proceeded. When extracts of the ungerminated spores were prepared with mortar and pestle, very little or no enzyme activity was detected. When the extracts were prepared with a mechanical homogenizer, however, they exhibited some enzyme activity, although less than did the extracts from germinated spores. Enzyme activities from germinated spores were approximately the same, regardless of the method of preparation. The …
The Prairie Naturalist Volume 1, No. 3. September, 1969
The Prairie Naturalist Volume 1, No. 3. September, 1969
The Prairie Naturalist
EDITORIAL: A VOICE FOR CONSERVATION ▪ Paul B. Kannowski
CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA—1968 ▪ Robert N. Randall
SOME ENVIRONMENTAL MANAGEMENT PROBLEMS AND PROPOSED SOLUTIONS ▪ Laurence R. Jahn
SOME PLANTS OF WESTERN MINNESOTA ▪ O. A. Stevens
MORTALITY OF MIGRATORY BIRDS AT GRAND FORKS, NORTH DAKOTA FOLLOWING A MOSQUITO CONTROL OPERATION IN MAY, 1969 ▪ Robert W. Seabloom, Lewis W. Oring and James R. Reilly
NESTING OF THE UPLAND PLOVER ON THE MISSOURI COTEAU ▪ K. F. Higgins, H. F. Duebbert and R. B. Oetting
NOTE
Albino sparrows discovered at Hazen, North Dakota ▪ Larry L. Kruckenberg and …
Thrips Of The Sagebrush-Grass Range Community In West-Central Utah, Ward Max Tingey
Thrips Of The Sagebrush-Grass Range Community In West-Central Utah, Ward Max Tingey
Theses and Dissertations
Three predominant and economically important shrubs of the sagebrush-grass range community in Utah, namely big sagebrush (Artemisia tridentata Nutt.), rubber rabbitbrush (Chrysothamnus nauseosus (Pall.) Britt.), antelope bitterbrush (Purshia tridentata (Pursh) DC), and a widely re-seeded range grass, crested wheatgrass (Agropyron cristatum (L.) Gaertn.) were sampled during the summers of 1966 and 1967, and yielded twenty species of thrips. Three species (Anaphothrips tricolor Moulton, Chirothrips aculeatus Bagnall, Chirothrips simplex Hood) were new distributional records for Utah. Seven species (Frankliniella n. sp. #1, Frankliniella n. sp. #2, Haplothrips n. sp., Leptothrips n. sp., Oedaleothrips n. sp., Sericothrips n. sp. #1, Sericothrips n. …
Flavonoid Chemotaxonomy Of Cacalia (Compositae), Paul Ernest Goldenbaum
Flavonoid Chemotaxonomy Of Cacalia (Compositae), Paul Ernest Goldenbaum
Masters Theses
No abstract provided.
A Study Of Multiple Embryo Development In The Netleaf Hackberry (Celtis Reticulata), Gary Porter Lawrence
A Study Of Multiple Embryo Development In The Netleaf Hackberry (Celtis Reticulata), Gary Porter Lawrence
Theses and Dissertations
Previous research has shown that polyembryony occurs in many species of the Ulmaceae. The purpose of this study was to determine the method of multiple embryo formation in netleaf hackberry, Celtis reticulata Torr. Collections of specimens were made throughout a two-year period. Collections were begun in early spring while the trees were still in the bud state. Collections were continued regularly throughout the growing season. The collections were preserved in FAA solution and were prepared for microscopic examination as follows: (1) The tertiary butyl paraffin method was used for dehydrating and embedding. (2) Sectioning was done on a rotary microtome …
Field Observations And Laboratory Studies On Growth And Tillering In Seedlings Of Oryzopsis Hymenoides As Affected By Selected Environmental Factors Of The Sand Dunes Of Lynndyl, Utah, Leopold B. Smigelski
Field Observations And Laboratory Studies On Growth And Tillering In Seedlings Of Oryzopsis Hymenoides As Affected By Selected Environmental Factors Of The Sand Dunes Of Lynndyl, Utah, Leopold B. Smigelski
Theses and Dissertations
Seedlings of Indian rice grass Oryzopsis hvmenoides (Roem. & Shult.) Ricker. were studied to determine the effect of soil moisture, photoperiod, depth of burial of germinated grains, temperature, and the rate of soil accumulation on seedling growth and tillering. The study was performed in two phases: Field observations and laboratory studies. Field observations were made on a system of sand dunes located northwest of Lynndyl, Utah. General observations were made from January, 1966 to May, 1968.
The Uptake Of Calcium By Iso Lines And Kentucky Varieties Of Nicotiana Tabacum L., Francis J. Shay
The Uptake Of Calcium By Iso Lines And Kentucky Varieties Of Nicotiana Tabacum L., Francis J. Shay
Morehead State Theses and Dissertations
A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Francis J. Shay on July 18, 1968.
End Matter, Vol. 9 No. 4
Brigham Young University Science Bulletin, Biological Series
No abstract provided.
Osteology And Myology Of Phrynosoma P. Platyrhinos Girard And Phrynosoma D. Hernandesi Girard, Richard L. Jenkins, Wilmer W. Tanner
Osteology And Myology Of Phrynosoma P. Platyrhinos Girard And Phrynosoma D. Hernandesi Girard, Richard L. Jenkins, Wilmer W. Tanner
Brigham Young University Science Bulletin, Biological Series
This study confirms the work of Etheridge (1964) in suggesting the peculiarity of the genus Phrynosoma within the family Iguanidae. The anterior osteology and myology of Phrynosoma platyrhinos platyrhinos Girard and Phrynosoma douglassi hernandesi Girard indicate Phrynosoma to be highly specialized and to differ significantlv from the Iguanid structure as portrayed by Oelrich (1956), Robison and Tanner (1962), and Avery and Tanner (1964). They also differ because of: ( 1 ) absence of lacrimal and postfrontal bones; (2) occurrence of occipital (also mandibular and temporal) spines; (3) posterodorsal shift of the skull elements; (4) divided nature of the M. sternohyoideus, …
Front Matter, Vol. 10 No. 1
Brigham Young University Science Bulletin, Biological Series
No abstract provided.
Front Matter, Vol. 9 No. 4
Brigham Young University Science Bulletin, Biological Series
No abstract provided.
End Matter, Vol. 10 No. 1
Brigham Young University Science Bulletin, Biological Series
No abstract provided.
Ticks Of The National Reactor Testing Station, Dorald M. Allred
Ticks Of The National Reactor Testing Station, Dorald M. Allred
Brigham Young University Science Bulletin, Biological Series
During the period from June, 1966, to September, 1967, 27 amphibians of two species, 446 reptiles of eight species, 561 birds of 81 species, and 4050 mammals of 26 species were examined for ectoparasites at the National Reactor Testing Station in southern Idaho. Of seven species of ticks collected, the predominant one was Ixodes kingi, found on mammals of 12 species. Next in abundance was Dermacentor andersoni found on birds of three species and mammals of 16 species. Haemaphysalis leporispalustris was taken from birds of 10 species and six spvecies of mammals. Four other species of Ixodes were taken from …
Notes On The Fern Family Matoniaceae From The Western United States, Samuel R. Rushforth
Notes On The Fern Family Matoniaceae From The Western United States, Samuel R. Rushforth
Theses and Dissertations
A Cretaceous fern flora haas been recently discovered near Westwater, Grand County, Utah. Among specimens collected from Westwater are many forms related to extant members of the fern family Matoniaceae. This family was widely distributed geographically throughout most of the Mesozoic Era, and matoniaceous ferns have been collected from several fossil localities in the United States. The Matoniaceae was especially important in the United States during Lower Cretaceous times. Five species, Matonidium brownii Rushforth, Matonidium lanceopennis Rushforth, Matonidium galleyi (Miner) Rushforth, Matonidium americanum Berry em. Rushforth, and Matonidium sp., and one variety, Matonidium brownii var. extenda Rushforth, are considered in …
The Prairie Naturalist Volume 1, No. 2. May, 1969
The Prairie Naturalist Volume 1, No. 2. May, 1969
The Prairie Naturalist
EDITORIAL: North Dakota's Naturalist-at-Large ▪ Paul B. Kannowski
WETLAND VEGETATION OF THE TURTLE MOUNTAINS, NORTH DAKOTA ▪ Robert L. Burgess and Dennis T. Disrud
RAPID METHOD OF FILTRATION OF MARSH WATERS ▪ V. A. Adomaitis and J. A. Shoesmith
NOTES
Additional distribution records of the false map turtle and the short-horned lizard in North Dakota ▪ Dennis J. Gemmell
Summer record of the snowy owl in North Dakota ▪ Donald R. Johnson
Long-billed curlews in LaMoure County, North Dakota ▪ Gary L. Krapu
Ultrastructural Investigations Of Powdery Mildew Of Rose Caused By Sphaerotheca Pannosa (Wallr.) Lev, Ani Clipper Watene
Ultrastructural Investigations Of Powdery Mildew Of Rose Caused By Sphaerotheca Pannosa (Wallr.) Lev, Ani Clipper Watene
Theses and Dissertations
The purpose of this study was to evaluate the ultrastructural aspects of the host-pathogen relationship between the fungus Sphaerotheca pannosa (Wallr.) Lev. and a susceptible horticultural variety of floribunda rose "Eutin". Attention was given to the penetration of hyphal tubes, and their subsequent development into: haustorial elements in epidermal cells of rose. In addition, changes in the morphology of infected epidermal cells were described. Thin sections of rose leaves infected with S. pannosa were examined in a Hitachi electron microscope, model HS-7, after glutaraldehyde-acrolein fixation, OsO4-uranyl acetate staining, and embedding in Epon plastic. The components of S. pannosa haustoria consisted …
Isolation And Partial Characterization Of The Toxic Substance From Eremocarpus Setigerus Benth, Shuliang Lee
Isolation And Partial Characterization Of The Toxic Substance From Eremocarpus Setigerus Benth, Shuliang Lee
Loma Linda University Electronic Theses, Dissertations & Projects
The work on the active substance of Eremocarpus setigerus Benth has been previously performed by Naito and Noller. However, the investigation was not complete. Therefore we isolated and tested this substance by steam distillation and thin layer chromatography technique. A yellow sticky toxic substance was isolated with Rf values of 0.15 in benzene system and 0.57 in benzene-absolute ethanol (95:5 v/v) system.
The toxic substance which is free of halogen, nitrogen, and sulfur, is soluble in ethyl ether, ethanol, and concentrated sulfuric acid. It has a maximum absorption in the ultraviolet region that indicates the presence of unsaturation. Its infrared …
Effect Of Gibberellic Acid And Chilling On Nucleic Acids During Germination Of Dormant Peach Seed, Yuh-Nan Lin
Effect Of Gibberellic Acid And Chilling On Nucleic Acids During Germination Of Dormant Peach Seed, Yuh-Nan Lin
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A study of nucleic acid changes influenced by gibberellic acid and chilling treatments in peach seed was performed in an attempt to reach a better understanding of the mechanism involved in breaking seed dormancy.
Gibberellic acid and the chilling treatment increased the RNA content. These two treatments which break dormancy also increased RNA, suggesting a similar mechanism involving RNA. Chilled seeds contained more RNA than did the gibberellic acid treated seeds.
DNA content remained unchanged regardless of treatment.
Dry seed had a greater ribonuclease activity than with soaked seeds. Enzyme changes did not correlate well with the RNA content in …
An Experimental Study Of Variation Within And Between Populations Of Petrophytum Caespitosum (Nutt.) Rydb. With Emphasis On Numerical Techniques, Frank R. Drysdale
An Experimental Study Of Variation Within And Between Populations Of Petrophytum Caespitosum (Nutt.) Rydb. With Emphasis On Numerical Techniques, Frank R. Drysdale
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Nine populations of sixty-eight individuals representing the distribution of Petrophytum caespitosum (Nutt.) Rydb. (Rosaceae) in the Intermountain Region were investigated for taxonomically significant variation using numerical techniques. On the basis of 19 morphological characters 3 subspecific taxa are recognized. Two taxa are existing subspecies: P. caespitosum (Nutt.) Rydb. var. caespitosum and P. caespitosum (Nutt.) Rydb. var. elatius (S. Wats.) Tides. One new subspecies is described: P. caespitosum (Nutt.) Rydb. var. latifolium. The ecology of the species is discussed. The floral and vegetative anatomy are described. Chromosome counts of 3 populations have given n = 9. A list of herbarium …
A Biosystematic Study Of The Genus Aconitum (Ranunculaceae) In The Intermountain Region, Rex Cates
A Biosystematic Study Of The Genus Aconitum (Ranunculaceae) In The Intermountain Region, Rex Cates
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
This study dealt with the Intermountain aconites of which the chromosome number of n = 8 was obtained.
The bumblebees, Bombus rufocinctus Cresson, B. appositus Cresson, and B. centralis Cresson, are the major pollinators of the allogamous and autogamous aconites.
Two-dimensional thin layer chromatography of cauline leaf extracts showed that the Intermountain aconites studied here consist of one chemical group.
The overall evidence indicates that the Intermountain aconites consist of one species, Aconitum columbianum Nutt., with two varieties, variety columbianum and variety ochroleucum A. Nels.