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Effects Of Two Species Of Va Mycorrhizal Fungi On Drought Tolerance Of Winter Wheat, Michael F. Allen, Michael G. Boosalis

Department of Plant Pathology: Faculty Publications

Roots and soils from western Nebraska fields of native and planted grasslands, and winter wheat of varied fallow-wheat cultivation duration, were evaluated for vesicular-arbuscular (VA) mycorrhizal root infection and spore numbers and types. Increased cultivation decreased percentage mycorrhizal infection in wheat and reduced spore numbers of Glomus fasciculatus, the dominant VA mycorrhizal fungus in these soils. Spore numbers of other VA mycorrhizal fungi did not change significantly with cultivation although mean numbers of G. mosseae increased with continued wheat production. Water relations and growth were determined for greenhouse-grown non-mycorrhizal, G. fasciculatus-infected, and G. mosseae-infected wheat in wet …

A Biosystematic Study Of The Polemonium Reptans L. Complex In The Eastern United States Including P. Reptans L. Var. Reptans, P. Reptans L. Var. Villosum Braun And Related Taxa (Polemoniaceae), Bill Lucas

Theses, Dissertations and Capstones

The taxonanic relationship of Polemoniun reptans L. var. reptans and P. reptans L. var. villosum Braun (Polemoniaceae) is examined in this studly. The former taxon occurs throughout most of the eastern deciduous forest while the latter is rare and limited to southern Ohio and northcentral Kentucky. The natural coherence of the species has provided a bimodal frequency distribution which displays clustering of the two varieties at opposite ends of a continuum. Significant differences were obtained using the BMDP7M multivariate analysis (0.05 level of significance) based on morphometric information gathered from herbarium specimens throughout the midwest and eastern states, between var. …

Taxonomic Limits Of The Genus Nagelus (Thorne And Malek, ]968) Siddiqi, 1979 With A Description Of Nagelus Borealis N.Sp. From Alaska, Thomas O. Powers, James G. Baldwin, A. H. Bell

Department of Plant Pathology: Faculty Publications

Tire genus Nagelus (Thorne and Malek, 1968) Siddiqi, 1979 is modified and a new species from Alaska is described. The combination of scanning electron microscopy and light microscopy permits the characterization of Nagelus spp. as having a broadly oval face pattern, no longitudinal striations on the lip region, deirids surrounded by six incisures, and an irregularly tapering tail with a large hyaline region. Nagelus leptus (Allen, 1955) Siddiqi, 1979, N. alpensis Doucet and Luc, 1981, N. camelliae (Kheiri, 1972) Siddiqi, 1979, N. jamelensis (Nesterov, 1973) Siddiqi, 1979, and N. obscurus (Allen, 1955) n. comb. are retained on this basis. Nagelus …

Proceedings Of The 9th Annual Meeting, Southern Soybean Disease Workers (April 14-15, 1982, Ft. Walton Beach, Florida): Better Yield, Higher Quality = Greater Profit, Walter J. Walla, Wayne Winner, H. Jack Walters, Jerry Berggren, J. Dan Smith

Southern Soybean Disease Workers: Conference Proceedings

Contents

1982 Southern Soybean Disease Workers Officers

1982 Southern Soybean Disease Workers Program Committee

Committee Chairmen

General session

Presidential address. Walter Walla

Role of American Soybean Association in Soybean Production. KL. Bader

Agricultural Chemistry World Wide. D Wolf

Soybean disease management. W Winner presiding

Soybean Disease Loss Estimate. E Koldenhoven

Disease Management Panel Discussion: The Consultant and Soybean Disease Control. R Carver

Disease Management: Chemical Industries' Point of View. HL McMenemy

Management Tactics for Soybean Diseases. DP Schmitt

Farmer and Soybean Disease Control. J Andries

Soybean nematodes. J Arnett presiding

Standardized Nematicide Research Report. A Wrather

Nematode Parasites …

Viruses Of Symbiotic Chlorella-Like Algae Isolated From Paramecium Bursaria And Hydra Viridis, James L. Van Etten, Russel H. Meints, Daniel Kuczmarski, Dwight E. Burbank, Kit Lee

Department of Plant Pathology: Faculty Publications

We previously reported that isolation of symbiotic Chloreila-like algae from the Florida strain of Hydra viridis induced replication of a virus (designated HVCV-1) in the algae. We now report that isolation ofsymbiotic Chlorella-like algae from four other sources of green hydra and one source ofthe protozoan Paramecium bursaria also induced virus synthesis. Algae from one of these hydra contained a virus identical to HVCV-1 (based on its rate of sedimentation, buoyant density, reaction to HVCV-1 antiserum, and DNA restriction fragments) whereas algae from the other three hydra contained. another similar, but distinct, virus (designated HVCV-2). The virus from the paramecium …

Influence Of Vesicular-Arbuscular Mycorrhizae On Water Movement Through Bouteloua Gracilis (H.B.K.) Lag Ex Steud, Michael F. Allen

Department of Plant Pathology: Faculty Publications

Root growth characteristics and water transport were compared between non-mycorrhizal Bouteloua gracilis and vesicular-arbuscular mycorrhizal Bouteloua gracilis infected with Glomus fasciculatus. Mycorrhizal plants did not have significantly different leaf area or root length from non-mycorrhizal plants, hut did have significantly fewer and shorter root hairs. Mycorrhizal plants had 50% lower leaf resistance with no change in leaf or root water potentials; thus transpiration was increased 100% with a 50% reduction in whole-plant, soil-to-root and root-to-leaf resistance. Assuming that the difference in water uptake was due to transport via the mycorrhizal hyphae, estimated fungus-to-root transport was 2◦8 x 10^{-5 …}

Host Reactions And Physical Properties Of Four Isolates Of Tobacco Ringspot Virus, Lisa Smith, James M. Mcguire

Journal of the Arkansas Academy of Science

No abstract provided.

The Plant Pathogenic Corynebacteria, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

The plant pathogenic corynebacteria are a fascinating group of bacteria that produce effects as diverse as any in the microbial world, ranging from wilts to abnormal growths. Several new pathogens have been discovered since this group was reviewed by Jensen (75), Starr (157), and Lelliott (96). Most subsequent reviews have dealt with taxonomy. The areas covered in this review necessarily reflect my biases and limitations. However, this review attempts to be comprehensive in some areas, and it calls attention to other areas that would benefit from more detailed investigation.

Impact, Epidemiology And Control Of Crown And Root Rot Of Spring Barley In Utah, Rastri Dey Kidambi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A three year study was initiated to study impact, epidemiology and control aspects of crown and root rot of irrigated and dryland spring barley in Utah. Isolations from leading edges of necrotic lesions of infected plants showed Cochliobolus sativus to be most frequently isolated. Yield loss studies showed that the disease had it's greatest effect in kernel weight reduction.

Time course studies of disease initiation, development and progress were made throughout two consecutive growing seasons. Disease initiation began 25-30 days after planting and reached maximum levels at approximately 60-80 days. Soil inoculum levels were determined by the flotation viability method …

Crown And Root Rot Of Alfalfa In Utah, Victoria Allard Turner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Symptoms of dark crown necrosis were found in all fields and varieties of alfalfa examined throughout the state. No significant differences were noted among varieties in 1 year old test plots in the amount of disease (Disease Index = D.I.) present in crown tissue. Significant differences were noted in plots 2.4 years and older among the different varieties. Varieties common to all plots did not differ overall; however, varieties responded differently according to location.

Fusarium spp. were most frequently isolated from affected crowns throughout the state, yet, differences in occurrence of species among the different aged plots and fields were …

Influence Of Phosphate Source On Vesicular-Arbuscular Mycorrhizae Of Bouteloua Gracilis, Michael F. Allen, James C. Sexton, Thomas S. Moore Jr., Martha Christensen

Department of Plant Pathology: Faculty Publications

Non-mycorrhizal and vesicular-arbuscular mycorrhizal Bouteloua gracilis infected with Glomus fasciculatus were grown in defined media containing different phosphate sources and compared with respect to phosphate content and form, biomass, chlorophyll concentration, and root phosphatase activity. The phosphate sources were sodium monobasic phosphate, a mixture of sodium monobasic phosphate and calcium phytate, and calcium phytate. Inositol and inositol plus calcium were added to the sodium phosphate medium as additional treatments. Mycorrhizal infection was highest in roots of plants grown in the presence of phytate (75%). Lower root infection levels were noted in plants from the sodium phosphate (19%) and mixed phosphate …

Effects Of Reduced Tillage And Multiple Cropping On Plant Diseases, Donald R. Sumner, Ben Doupnik Jr., M. G. Boosalis

Department of Plant Pathology: Faculty Publications

In the past, tillage research on plant diseases was concerned primarily with practices that buried plant residues in single-crop production systems. The burial of plant debris to destroy pathogens is an ancient agricultural prac­ tice (34). Each crop was tested as a single entity, and most crop rotations were based on one crop per year. Interest in notill and conservation tillage systems and mUltiple cropping has increased in the past two decades be­ cause of the scarcity and increased cost of fossil fuels, periodic world food shortages, and the concern over soil erosion (73,110). These concerns are of such paramount …

Proceedings Of The 8th Annual Meeting, Southern Soybean Disease Workers (March 11-12, 1981, Memphis, Tennessee): Soybeans, The Crop Of The Future

Southern Soybean Disease Workers: Conference Proceedings

General Session

Presidential Address - Glen Whitney

The Influence of Plant Diseases on American Agriculture - Wiley Garrett

Integrated Pest Management: A National Prospective - B. Blair

Development in Brazil, the Future World Supplier of Food: Industry Overview - Ray Smith

Soybean Disease Loss Estimate - R. V. Sturgeon

Soybeans, Seed, Seedling, and Soil-Borne Disease, James Kantzes presiding

Standardized Seed Treatment Research Report - M. C. McDaniel

Soybean Seedling Disease Control and Plant Populations - Norman Horn

Metalaxyl: A New Seed Dressing and Soil Treatment Fungicide - H. V. Morton and D. Houseworth

Soybean Seed Treatment: U. S. Status …

Comparative Water Relations And Photosynthesis Of Mycorrhizal And Non-Mycorrhizal Bouteloua Gracilis H.B.K. Lag Ex Steud., Michael F. Allen, William K. Smith, Thomas S. Moore Jr., Martha Christensen

Department of Plant Pathology: Faculty Publications

The rangeland grass, Bouteloua gracilis was inoculated with its mycorrhizal symbiont, Glomus fasciculatus, to determine the influence of vesicular-arhuscular mycorrhizae on water status, stomatal behaviour and photosynthesis as well as gross plant morphology, biomass and phosphorus content. Mycorrhizal infection increased transpiration rates by over 100% with 50 to 70% lower leaf resistances to water vapour diffusion. Leaf xylem pressure was not different between mycorrhizal and non-mycorrhizal plants indicating that whole-plant resistance to water transport was reduced by more than 50%. Photosynthetic rates under saturating light conditions increased 68% with infection as a consequence of a 33% reduction in stomatal …

Germination And Haustorial Development In Orobanche Minor Smith (Orobanchaceae), David L. Spelce

Biological Sciences Theses & Dissertations

Orobanche minor Smith is an introduced root parasite that is known to attack some commercial crops. Germination occurs only after a preconditioning period involving moisture which must be followed by a chemical stimulant produced by the host root. Strigol and strigol analogs (GR-compounds} have been reported to germinate some species of Orobanche. Statistical tests indicate a significant difference between the effectiveness of strigol, GR-7 and GR-45 (P = 0.001).

The embryo is an undifferentiated mass of cells. During germination, the radicular pole of the embryo differentiates into the radicle, while the plumular pole remains undifferentiated. The radicle forms the primary …

The Influence Of Atrazine (2-Chloro-4-(Ethylamino)-6-(Isopropylamino-S-Triazine) On The Severity Of Gibberella Zeae-Induced Seedling Blight Of Corn, Louis A. Heaton

Masters Theses

Three corn inbreds were grown in artificially inoculated, steamed greenhouse soil amended with atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) to determine the herbicide's effect on the severity of Gibberella zeae (Schwabe) Petch-induced seedling blight. Corn inbreds used were Gibberella-resistant (FR632), Gibberella-intermediate (FRMo17), and Gibberella-susceptible (C123^HT). Soils were amended with atrazine at rates of 2, 15, and 30 ppm.

Susceptible inbred seedlings showed no response to the herbicide with symptims equally severe in controls and all 3 concentrations of atrazine. Intermediate inbred seedlings grown in all atrazine amended soils showed significantly more severe disease symptoms than controls. Soil amended with …

A Guide To The Threatened And Endangered Vascular Plants Of The Lake Mead National Recreation Area, James S. Holland, Wesley E. Niles, Charles L. Douglas, Dennis R. Schramm

Publications (WR)

This illustrated guide was prepared to provide the botanical community, land managers, and other interested persons with a reference that describes and locates the twelve plant taxa currently being considered by the Fish and Wildlife Service for threatened or endangered status in or around the Lake Mead National Recreation Area. The guide is intended to assist managers of government agencies in determining the presence of these species and in defining management programs for their protection. The guide should be consulted prior to any construction project. If a potential conflict is identified, an onsite evaluation should be conducted early in the …

Ryegrass Toxicity Organism Found On Other Grasses, D L. Chatel, J. L. Wise, A. G. Marfleet

Journal of the Department of Agriculture, Western Australia, Series 4

Yellow slime disease caused by Corynebacterium sp. has recently been found in three grass species.

The diseased grasses were found in the field growing with each other and with affected toxic annual ryegrass.

A New Tissue Test For Accurate Diagnosis Of Copper Deficiency In Cereals, J W. Gartrell, A. D. Robson, J. F. Loneragan

Journal of the Department of Agriculture, Western Australia, Series 4

Copper deficiency in ceereals can now be accurately diagnosed using tissue analysis.

Variation In Leaf Anatomy In Ten Selected Species Of Carex (Cyperaceae) Representing Three Subgeneric Sections (Bracteosae, Multiflorae, And Squarrosae), Marion Rae Mallory

Theses, Dissertations and Capstones

Leaves of Carex (Cyperaceae) representing three subgeneric sections were collected from wide spread localities and observed for anatomical variation. Among the quantitative characters evaluated were, epidermal cell height, width, and number per unit area, bulliform cell height and width, ai r cavity length, width, and number per unit area, and number of stomata per unit area. some descriptive anatomical characters were leaf and keel shape, air cavity shape, sclerenchyma pattern, vascular bundle location, presence or absence of a hypodermis, nature of the mesophyll, silica body shape and location, presence or absence of epidermal projections, stomatal pattern, and subsidiary cell shape.

Proceedings Of The 6th Annual Meeting, Southern Soybean Disease Workers (March 13-15, 1979, Hot Springs, Arkansas): Healthy Beans, A Key To Profit

Southern Soybean Disease Workers: Conference Proceedings

Contents

Schedule, Committees, Officers

The Gold That Grows, John Stephens

IPM Program, Joe Good

The Role of the Ag Consultant - Dick Jensen

Seed Quality, Ron Hager

Nematode-Economic Threshold, Don Schmitt

Problems of Marketing Foliar Fungicides, Gordon Elliott and Nic Thomas

Results of Point System in Determining Application Time, Billy Moore

Disease Loss Report, R. V. Sturgeon

Seed Treatment Report, M. C. McDaniel

SSDW Financial Status Report, Sid Stephens

Update of FIFRA and RPAR, Curtis L. Mason

Needs and Effects of a Foliar Fungicide - B. C. Smale

The Effect of Bean Pod Mottle, Soybean Mosaic and Bean Yellow Mosaic …

Lake Itasca State Park Myxomycetes: An Annotated Checklist, M. E. Palm, E. L. Stewart, E. F. Haskins

Journal of the Minnesota Academy of Science

A lack of published information regarding Minnesota Myxomycetes prompted attempts to document species from Lake Itasca State Park in Clearwater county, in the northwest part of the state. Seventy-five species are herein recorded from 341 collections made during the years 1959, 1971,and 1975-78.

Bacteriocin-Like Substances Produced By Rhizobium Japonicum And Other Slow-Growing Rhizobia, D. C. Gross, A. K. Vidaver

Department of Plant Pathology: Faculty Publications

Bacteriocin-like substances were commonly produced by slow-growing Rhizobium japonicum and cowpea rhizobia on an L-arabinose medium. Antagonism between strains of R. japonicum was not detected in vitro; however, such strains were often sensitive to some bacteriocins produced by cowpea rhizobia. Inhibitory zones (2 to 8 mm from colony margins), produced by 58 of 66 R. japonicum test strains, were reproducibly detected with Corynebacterium nebraskense as an indicator. Quantitative production was not related to symbiotic properties of effective strains, since nine noninfective strains and one ineffective strain produced bacteriocin. Eight R. japonicum strains that did not produce bacteriocin nevertheless formed effective …

Vascular Vegetation And Flora Of Remnant Forest In The Ohio River Floodplain Between The Great Kanawha And Big Sandy Rivers, West Virginia, John Carl Furry

Theses, Dissertations and Capstones

A total of 246 species of vascular plants representing 75 families were recorded from six physiographically defined forest types in the Ohio River floodplain between the Greet Kanawha end Big Sandy Rivers, West Virginia. Distinct woodlands were those associated with the River flats, River front, bottoms of secondary streams, stream banks, the high floodplain end swamps. Only two species, Acer saccharinum and Platenus occidentalis representing 0.81 percent of the total species encountered, were present in all forest types; 105 species (42.7 percent) were restricted to one forest type. Fifty-five species were new additions to the flora of one or more …

Purification Of Some Legume Carlaviruses, Venkateswarlu Veerisetty, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

Purification schemes were developed which yielded 0.7 to 1.0 mg of alfalfa latent virus (ALV) and pea streak virus (PSV) and 0.1 to 0.3 mg of red clover vein mosaic virus (RCVMV) per gram pea cullivar Lincoln plant tissue (excluding roots). The freezing of the tissue and the use of an appropriate extraction buffer were crucial. Virus from sap was precipitated by 6%(w/v) polyethylene glycol (PEG, MW 6,000) and concentrated by two cycles of differential centrifugation. Partially purified virus preparations had a single nucleoprotein component in rate-zonal sucrose and equilibrium cesium chloride density gradient centrifugation. The virus preparations did not …

A Study Of Vascular Plants On Rock Outcrops In Southwestern West Virginia, Sheila Kay Adkins Zeto

Theses, Dissertations and Capstones

A total of 223 species of vascular plants representing 66 families were collected from rock outcrops at five study sites in Cabell, Wayne and Lincoln Counties, southwestern West Virginia. Eighteen species (8.07 percent) were present at all five sites with little regard for site conditions. One hundred seventeen species (52,4 percent) were restricted to only one of the five sites. The outcrop flora included nine species (5.03 percent) that are considered introduced elements, Forty-eight species were new additions to the flora of one or more of the counties studied, Floristic similarity coefficients of five sites range .from .347 to .512. …

Purification Of Some Legume Carlaviruses, Venkateswarlu Veerisetty, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

Purification schemes were developed which yielded 0.7 to 1.0 mg of alfalfa latent virus (ALV) and pea streak virus (PSV) and 0.1 to 0.3 mg of red clover vein mosaic virus (RCVMV) per gram pea cullivar Lincoln ) plant tissue (excluding roots). The freezing of the tissue and the use of an appropriate extraction buffer were crucial. Virus from sap was precipitated by 6%(w/v) polyethylene glycol (PEG, MW 6,000) and concentrated by two cycles of differential centrifugation. Partially purified virus preparations had a single nucleoprotein component in rate-zonal sucrose and equilibrium cesium chloride density gradient centrifugation. The virus preparations did …

Nitrogen Fixation (Acetylene Reduction) Associated With Roots Of Winter Wheat And Sorghum In Nebraska, Wayne L. Pedersen, K. Chakrabarty, R. V. Klucas, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

Root segments and root-soil cores (6.5-cm diameter) from fields and nurseries of winter wheat and sorghum were tested for N₂ fixation by using the acetylene reduction assay. Wheat samples (~1,200) from 109 sites generally had low or no activity (0 to 3.1 nmol of C₂H₄ produced per h per g [dry weight] of root segments), even after 24 h of incubation. However, a commercial field of Scout 66, located in western Nebraska, exhibited appreciable activity (290 nmol of C₂H₄ produced per h per g [dry weight] of root segments). Of 400 sorghum lines …

In Vitro Morphogenesis And Mutation Of Glycine Max L., Thomas Daniel Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soybean (Glycine max L. c.v. Consoy) tissue cultures were grown in synthetic media containing various concentrations and combinations of minerals, auxins, cytokinins, pH levels, and inorganic growth factors in a systematic procedure to establish optimum media for initiation and maintenance of callus. Further modification of the hormone level was employed to initiate callus morphogenesis. Normally toxic levels of atrazine were established in soybean calli media, and ethyl methanesulfonate (EMS) and X ray-induced mutant calli were selected for atrazine tolerance.

Optimal media for initiation and maintenance of soybean calli were developed and a defined medium was determined that consistently yields …

Multiple Forms Of Deoxyribonucleic Acid-Dependent Ribonucleic Acid Polymerase In Barley Leaves (Hordeum Vulgare L.), Sachchidananda Javali

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ribonucleic acid polymerases (E.C. 2.7.7.6) have been solubilized form whole green leaves of barley (Hordeum vulgare L.). Three major forms of the solubilized enzyme have been isolated by sonication in high ionic strength buffers, cation and anion exchange chromatography, and agarose gel permeation chromatography and designated I, II, and III. The enzyme fractions appear analogous to the Class I, II, and III ribonucleic acid polymerases defined in other eucaryotic systems. The ionic strength optima, amatoxin sensitivity, and relative activities with denatured calf thymus deoxyribonucleic acid were different for Class I, II, and III polymerases.

A simple, rapid, reproducible method …