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Flax As An Iowa Crop, Chas. S. Reddy, L. C. Burnett 2017 Iowa State College

Flax As An Iowa Crop, Chas. S. Reddy, L. C. Burnett

Bulletin (Iowa Agricultural Experiment Station)

Among the grain crops in the United States, seed flax is exceeded in value by corn, wheat, oats and barley. It has approximately the same value as rye, rice and sorghums.

As a crop for new land, the flax seed acreage reached a peak (3,700,000 acres) in 1902, but gradually declined to little more than a million acres by 1922. As a crop for old land, taking its place in rotations, flax acreage reached a second peak equal to the first in 1930. Consumption of flax in the United States surpassed production in 1909 and for the past ...


Control Of Cherry Yellow-Leaf On Nursery Stock, George L. McNew, Donald E. Bliss 2017 Iowa State College

Control Of Cherry Yellow-Leaf On Nursery Stock, George L. Mcnew, Donald E. Bliss

Bulletin (Iowa Agricultural Experiment Station)

Yellow-leaf, caused by the fungus Coccomyces hiemalis Higgins, is the most prevalent and destructive cherry disease in Iowa, since it often causes premature defoliation of both nursery and orchard trees. Early defoliation in nursery stock results in decreased growth during the current and subsequent years, and precludes all possibility of forcing the trees into marketable size in one growing season. In the orchard, defoliation may decrease fruit bud formation and vegetative growth and increase the amount of winterkilling.

All defoliated nursery stock must be held in the nursery row a second season, and even then many of the trees must ...


Materials And Method For Increasing A Plant's Resistance To Stress, Ling Li, Eve Syrkin Wurtele 2017 Iowa State University

Materials And Method For Increasing A Plant's Resistance To Stress, Ling Li, Eve Syrkin Wurtele

Ling Li

Method of increasing resistance to a pathogen or a pest in a plant comprising introducing into the plant and expressing therein a polynucleotide comprising a nucleotide sequence encoding a Qua-Quine Starch (QQS) polypeptide; method of producing a plant with increased resistance to a pathogen or a pest comprising crossing a plant obtained in accordance with the above method with a second plant to produce progeny plants and selecting progeny plants with increased resistance to a pathogen or a pest; a plant with increased resistance to a pathogen or a pest; a seed of the plant; a hybrid of the plant ...


Effects Of Eight Herbicides On In Vitro Hatching Of Heterodera Glycines, A. T. S. Wong, G. L. Tylka, R. G. Hartzler 2017 Iowa State University

Effects Of Eight Herbicides On In Vitro Hatching Of Heterodera Glycines, A. T. S. Wong, G. L. Tylka, R. G. Hartzler

Gregory Tylka

Laboratory studies were conducted to evaluate effects of selected herbicides on hatching of free eggs of the soybean cyst nematode, Heterodera glycines. The herbicides used were Atrazine (atrazine), Basagran (bentazon), Bladex (cyanazine), Blazer (acifluorfen), Command (clomazone), Lasso (alachlor), Sonalan (ethalfluralin), and Treflan (trifluralin). Treatments comprised two concentrations of commercial herbicide formulations and deionized water and 3.14 mM zinc sulfate as negative and positive controls, respectively. Eggs were extracted from females and cysts, surface disinfested, and incubated in herbicide or control solutions at 25 ± 2 C in darkness. Hatched second-stage juveniles were counted every other day for 24 days. Hatching ...


Flow Cytometric Analysis And Sorting Of Heterodera Glycines Eggs, G. L. Tylka, T. L. Niblack, T. C. Walk, K. R. Harkins, L. Barnett, N. K. Baker 2017 Iowa State University

Flow Cytometric Analysis And Sorting Of Heterodera Glycines Eggs, G. L. Tylka, T. L. Niblack, T. C. Walk, K. R. Harkins, L. Barnett, N. K. Baker

Gregory Tylka

A nondestructive technique was developed to characterize and separate eggs of soybean cyst nematode, Heterodera glycines, by developmental stage using flow cytometry. Eggs from cysts cultured on susceptible soybean roots were suspended in 0.1% xanthan gum or 59% sucrose and loaded into either a Coulter EPICS 752 or EPICS 753 flow cytometer. Eggs were analyzed and sorted according to forward angle and 90º light scatter, flow cytometric parameters that are relative measures of object size and granularity, respectively. Mature eggs containing vermiform juveniles were less granular and slightly larger than eggs in earlier stages of embryogeny, allowing for separation ...


A Screen For Arabidopsis Thalianamutants With Altered Susceptibility To Heterodera Schachtii, T. J. Baum, M. J. E. Wubben II, K. A. Hardy, H. Su, S. R. Rodermel 2017 Iowa State University

A Screen For Arabidopsis Thalianamutants With Altered Susceptibility To Heterodera Schachtii, T. J. Baum, M. J. E. Wubben Ii, K. A. Hardy, H. Su, S. R. Rodermel

Thomas Baum

Genetic approaches are a powerful means to elucidate plant-pathogen interactions. An in vitro screening protocol was developed to identify Arabidopsis thaliana mutants with altered susceptibility to Heterodera schachtii, the sugar beet cyst nematode. In an initial screen of approximately 5,200 ethyl methanesulfonate-generated mutant plants, two stable mutations were identified. Both mutant lines were backcrossed and were found to harbor single recessive mutant alleles. Mutant line 2-4-6 shows an approximately two-fold increase in sedentary and developing nematodes, while mutant line 10-5-2 exhibits a significant decrease in susceptibility that manifests itself only after nematodes become sedentary. Analyses of progeny from crosses ...


Isolation Of Beta-1,4-Endoglucanase Genes From Globodera Tabacumand Their Expression During Parasitism, M. Goellner, G. Smant, J. M. De Boer, T. J. Baum, E. L. Davis 2017 North Carolina State University

Isolation Of Beta-1,4-Endoglucanase Genes From Globodera Tabacumand Their Expression During Parasitism, M. Goellner, G. Smant, J. M. De Boer, T. J. Baum, E. L. Davis

Thomas Baum

Two beta-1,4-endoglucanase (EGase) cDNAs were isolated from Globodera tabacum, the tobacco cyst nematode, and have been designated as GT-eng-1 and GT-eng-2. GT-eng-1 and GT-eng-2 encode precursor proteins with a predicted secretion signal sequence, cellulolytic catalytic domain, and a linker domain. The protein product GT-ENG-1 contains an additional 95 amino acid carboxy terminal sequence with strong similarity to type II cellulose binding domains. Riboprobes and polyclonal antibodies raised to recombinant cyst nematode EGases were used to follow expression patterns of EGase transcripts and proteins throughout the nematode life cycle. EGase transcripts and proteins were specifically detected within the subventral esophageal ...


Cloning Of A Putative Pectate Lyase Gene Expressed In The Subventral Esophageal Glands Of Heterodera Glycines, J. M. de Boer, J. P. McDermott, E. L. Davis, R. S. Hussey, H. Popeijus, G. Smant, T. J. Baum 2017 Iowa State University

Cloning Of A Putative Pectate Lyase Gene Expressed In The Subventral Esophageal Glands Of Heterodera Glycines, J. M. De Boer, J. P. Mcdermott, E. L. Davis, R. S. Hussey, H. Popeijus, G. Smant, T. J. Baum

Thomas Baum

We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level to a pectate lyase from Globodera rostochiensis. In situ hybridizations showed that the corresponding gene (Hg-pel-1) is expressed in the subventral esophageal gland cells of second-stage juveniles. The deduced amino acid sequence of the H. glycines cDNA shows homology to class III pectate lyases of bacterial and fungal origin.


Cabbage Yellows, Caused By Fusarium Conglutinans, In Iowa, I. E. Melhus, A. T. Erwin, Frank Van Haltern 2017 Iowa State College

Cabbage Yellows, Caused By Fusarium Conglutinans, In Iowa, I. E. Melhus, A. T. Erwin, Frank Van Haltern

Bulletin (Iowa Agricultural Experiment Station)

Cabbage yellows caused by Fusarium conglutinans is widely distributed in Iowa. It probably was introduced into the state just previous to 1910 on cabbage transplants shipped from the southern states. The organism causing cabbage yellows is the chief limiting factor in cabbage production in the Muscatine Island section and contiguous territory on the Iowa side of the Mississippi River. The yellows organism may live in the soil for long periods of time, at least 11 years, and still be destructive to a cabbage crop. Cabbage, cauliflower, Chinese cabbage, kohlrabi and brussels sprouts are known to be hosts of this organism ...


Differences In Hatching Of Heterodera Glycines Egg-Mass And Encysted Eggs In Vitro, J. M. Thompson, G. L. Tylka 2017 Iowa State University

Differences In Hatching Of Heterodera Glycines Egg-Mass And Encysted Eggs In Vitro, J. M. Thompson, G. L. Tylka

Gregory Tylka

Hatching studies with Heterodera glycines typically have been conducted with a mixture of egg-mass and encysted eggs. Laboratory research was conducted to compare hatching of H. glycines eggs from external egg masses with that of eggs extracted from within females and cysts (encysted eggs). Egg-mass eggs were collected by soaking infected soybean roots in 0.5% sodium hypochlorite, and encysted eggs were collected from females and cysts dislodged from the same roots with a stream of water. Eggs were incubated at 25ºC in deionized water, 3.0 mM ZnSO[sub4]solution, or one of three synthetic H. glycines hatch inhibitors ...


Responses Of Heterodera Glycines Populations To A Postemergence Herbicide Mixture And Simulated Insect Defoliation, J. A. Browde, G. L. Tylka, L. P. Pedigo, M. D. K. Owen 2017 Iowa State University

Responses Of Heterodera Glycines Populations To A Postemergence Herbicide Mixture And Simulated Insect Defoliation, J. A. Browde, G. L. Tylka, L. P. Pedigo, M. D. K. Owen

Gregory Tylka

Effects of a mixture of the postemergence herbicides acifluorfen and bentazon, and simulated defoliation expected from green cloverworm on population densities of Heterodera glycines were determined in field plots in Iowa. The herbicide mixture and defoliation each suppressed soybean growth. Population densities of H. glycines were generally lower in herbicide-treated than untreated plots. Population densities of the nematode were unaffected by defoliation in 1988 and 1990-91, but were increased by the treatment in 1989. Key words: acifluorfen, bentazon, defoliation, Glycine max, green cloverworm, herbicide, Heterodera glycines, nematode, Plathypena scabra, postemergence herbicides, soybean, soybean cyst nematode.


Effects Of Zinc Fertilization Of Corn On Hatching Of Heterodera Glycines In Soil, J. E. Behm, G. L. Tylka, T. L. Niblack, W. J. Wiebold, P. A. Donald 2017 Iowa State University

Effects Of Zinc Fertilization Of Corn On Hatching Of Heterodera Glycines In Soil, J. E. Behm, G. L. Tylka, T. L. Niblack, W. J. Wiebold, P. A. Donald

Gregory Tylka

Experiments were conducted to determine the effects of zinc fertilizers on hatching and soil population densities of Heterodera glycines. In vitro egg hatching in solutions of reagent-grade zinc sulfate and zinc chloride and fertilizer-grade zinc sulfate was significantly greater than hatching in deionized water, whereas zinc chelate fertilizer significantly inhibited egg hatching relative to deionized water. In greenhouse experiments, no differences in cumulative percentage egg hatch were detected in soil naturally infested with H. glycines amended with fertilizer-grade zinc sulfate and zinc chelate at rates equivalent to 0, 1.12, 11.2, and 112 kg Zn/ha and subsequently planted ...


Heterodera Glycines Cyst Components And Surface Disinfestants Affect H. Glycines Hatching, D. V. Charlson, G. L. Tylka 2017 Iowa State University

Heterodera Glycines Cyst Components And Surface Disinfestants Affect H. Glycines Hatching, D. V. Charlson, G. L. Tylka

Gregory Tylka

We investigated the effects of Heterodera glycines cyst components and surface disinfestants on hatching of H. glycines eggs in vitro. Eggs were incubated in either H. glycines cyst wall fragments, cyst wall and egg rinsate, egg homogenate, or control solutions of soybean root diffusate, sterile distilled water, or zinc sulfate. Hatch in cyst wall and egg rinsate, and egg homogenate, was greater ([alpha] = 0.05) than hatch in sterile distilled water; however, it was not different from hatch in zinc sulfate according to Dunnett's test. Hatch in cyst wall fragments was similar to hatch in sterile distilled water. To ...


Four New Fungous Diseases In Iowa, L. H. Pammel, Charlotte M. King 2017 Iowa State College

Four New Fungous Diseases In Iowa, L. H. Pammel, Charlotte M. King

Bulletin (Iowa Agricultural Experiment Station)

During the past two seasons several important destructive fungous diseases of cultivated plants have made their appearance in Iowa, namely: Timothy rust, alfalfa rust, apple canker, and onion smut.

About the middle of July, 1910, there was an abundance of timothy rust in a meadow in the vicinity of Ames; subsequently it was reported from other localities in the state. It was again noticed after the September rains in 1911, especially in the timothy breeding plots.


The Soybean Rhg1 Locus For Resistance To The Soybean Cyst Nematode Heterodera Glycines Regulates The Expression Of A Large Number Of Stress- And Defense-Related Genes In Degenerating Feeding Cells, Pramod Kaitheri Kandoth, Nagabhushana Ithal, Justin Recknor, Tom Maier, Dan Nettleton, Thomas J. Baum, Melissa G. Mitchum 2017 University of Missouri

The Soybean Rhg1 Locus For Resistance To The Soybean Cyst Nematode Heterodera Glycines Regulates The Expression Of A Large Number Of Stress- And Defense-Related Genes In Degenerating Feeding Cells, Pramod Kaitheri Kandoth, Nagabhushana Ithal, Justin Recknor, Tom Maier, Dan Nettleton, Thomas J. Baum, Melissa G. Mitchum

Thomas Baum

To gain new insights into the mechanism of soybean (Glycine max) resistance to the soybean cyst nematode (Heterodera glycines), we compared gene expression profiles of developing syncytia in soybean near-isogenic lines differing at Rhg1 (for resistance to Heterodera glycines), a major quantitative trait locus for resistance, by coupling laser capture microdissection with microarray analysis. Gene expression profiling revealed that 1,447 genes were differentially expressed between the two lines. Of these, 241 (16.8%) were stress- and defense-related genes. Several stress-related genes were up-regulated in the resistant line, including those encoding homologs of enzymes that lead to increased levels of ...


The Novel Cyst Nematode Effector Protein 19c07 Interacts With The Arabidopsis Auxin Influx Transporter Lax3 To Control Feeding Site Development, Chris Lee, Demosthenis Chronis, Charlotte Kenning, Benjamin Peret, Tarek Hewezi, Eric L. Davis, Thomas J. Baum, Richard Hussey, Malcolm Bennett, Melissa G. Mitchum 2017 University of Missouri

The Novel Cyst Nematode Effector Protein 19c07 Interacts With The Arabidopsis Auxin Influx Transporter Lax3 To Control Feeding Site Development, Chris Lee, Demosthenis Chronis, Charlotte Kenning, Benjamin Peret, Tarek Hewezi, Eric L. Davis, Thomas J. Baum, Richard Hussey, Malcolm Bennett, Melissa G. Mitchum

Thomas Baum

Plant-parasitic cyst nematodes penetrate plant roots and transform cells near the vasculature into specialized feeding sites called syncytia. Syncytia form by incorporating neighboring cells into a single fused cell by cell wall dissolution. This process is initiated via injection of esophageal gland cell effector proteins from the nematode stylet into the host cell. Once inside the cell, these proteins may interact with host proteins that regulate the phytohormone auxin, as cellular concentrations of auxin increase in developing syncytia. Soybean cyst nematode (Heterodera glycines) Hg19C07 is a novel effector protein expressed specifically in the dorsal gland cell during nematode parasitism. Here ...


Arabidopsis Spermidine Synthase Is Targeted By An Effector Protein Of The Cyst Nematode Heterodera Schachtii, Tarek Hewezi, Peter J. Howe, Tom R. Maier, Richard S. Hussey, Melissa G. Mitchum, Eric L. Davis, Thomas J. Baum 2017 Iowa State University

Arabidopsis Spermidine Synthase Is Targeted By An Effector Protein Of The Cyst Nematode Heterodera Schachtii, Tarek Hewezi, Peter J. Howe, Tom R. Maier, Richard S. Hussey, Melissa G. Mitchum, Eric L. Davis, Thomas J. Baum

Thomas Baum

Cyst nematodes are sedentary plant parasites that cause dramatic cellular changes in the plant root to form feeding cells, so-called syncytia. 10A06 is a cyst nematode secretory protein that is most likely secreted as an effector into the developing syncytia during early plant parasitism. A homolog of the uncharacterized soybean cyst nematode (Heterodera glycines), 10A06 gene was cloned from the sugar beet cyst nematode (Heterodera schachtii), which is able to infect Arabidopsis (Arabidopsis thaliana). Constitutive expression of 10A06 in Arabidopsis affected plant morphology and increased susceptibility to H. schachtii as well as to other plant pathogens. Using yeast two-hybrid assays ...


Eight Nonhost Weed Species Of Heterodera Glycines In Iowa, A. T. S. Wong, G. L. Tylka 2017 Iowa State University

Eight Nonhost Weed Species Of Heterodera Glycines In Iowa, A. T. S. Wong, G. L. Tylka

Gregory Tylka

The ability of the soybean cyst nematode (Heterodera glycines) to reproduce on eight weed species commonly occurring in Iowa was evaluated in greenhouse and field microplot experiments. Population densities of the nematode increased on H. g/ycines-susceptible soybean but not on H. g/ycines-resistant soybean, Canada thistle, cocklebur, eastern black nightshade, giant foxtail, lambsquarters, redroot pigweed, velvetleaf, and wild sunflower. All of the weeds evaluated were nonhosts of this H. glycines race 3 population.


Cedar Apple Fungi And Apple Rust In Iowa, L. H. Pammel 2017 Iowa State College

Cedar Apple Fungi And Apple Rust In Iowa, L. H. Pammel

Bulletin (Iowa Agricultural Experiment Station)

The subject of apple rust in this state has assumed considerable importance during the past season so that a treatment of the species of apple rust in Iowa will not be out of place.

A few years ago the writer of this bulletin prepared for the Division of Vegetable Physiology and Pathology, a paper on these rusts as affecting forest trees of the west. With the consent of Dr. Albert F. Woods, Chief of the Division, I present that portion of the above paper which deals with the apple rusts. I wish especially to express my thanks to Mrs, Patterson ...


Some Troublesome Weeds Of The Mustard Family., L. H. Pammel 2017 Iowa State College

Some Troublesome Weeds Of The Mustard Family., L. H. Pammel

Bulletin (Iowa Agricultural Experiment Station)

The mustards constitute a family well marked in many ways. So much so that most people readily recognize mustards. The Cruciferae, as the mustards are technically known, are widely distributed but occur chiefly in temperate and northern regions. They are largely represented in the Mediterranean region. As understood by different authors, there are from 1200 to 2000 species.


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