Other Plant Sciences Commons^™

Forage Yield And Economic Losses Associated With The Brown-Midrib Trait In Sudangrass, M. D. Casler, Jeffrey F. Pedersen, D. J. Undersander

Department of Agronomy and Horticulture: Faculty Publications

Brown-midrib genes increase digestibility due to reduced lignification in sudangrass, Sorghum bicolor subsp. drummondii (Nees ex Steud.) de Wet & Harlan. Brown-midrib lines are known to be low in forage yield potential, but this reduction in forage yield has not been previously quantified. The objectives of this study were to quantify the increase in forage quality and decrease in forage yield and to provide an economic assessment of this dichotomy. Piper and Greenleaf (normal leaves) were compared with their brown-midrib counterparts and four highly selected brown-midrib (FG) lines at two locations for 2 yr. Brown-midrib lines averaged 9.0% lower in …

Registration Of Rn582 Sorghum Germplasm Line, J. F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

RN582 sorghum [Sorghum bicolor (L.)Moench] germplasm line (Reg. no. GP-591, PI 628277) was developed jointly by the USDA-ARS and the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska, and was released in September 2001.

RN582 is an S₆ selection from the cross (RTx430 ms₃ms₃X E 35-1) X E 35-1. RTx430 was developed and released by the Texas Agricultural Experiment Station (Miller, 1984) and was provided to this project containing the nuclear male sterility gene ms₃ by A.B. Maunder in 1988. E 35-1 is an Ethiopian land race with white …

Diurnal Variation In The Basal Emission Rate Of Isoprene, Jennifer L. Funk, Clive G. Jones, Christine J. Baker, Heather M. Fuller, Christian P. Giardina, Manuel T. Lerdau

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Isoprene is emitted from numerous plant species and profoundly influences tropospheric chemistry. Due to the short lifetime of isoprene in the atmosphere, developing an understanding of emission patterns at small time scales is essential for modeling regional atmospheric chemistry processes. Previous studies suggest that diurnal fluctuations in isoprene emission may be substantial, leading to inaccuracies in emission estimates at larger scales. We examined diurnal patterns in the basal emission rate of isoprene in red oak (Quercus rubra), eastern cottonwood (Populus deltoides), and eucalyptus (Eucalyptus saligna) and the influence of light and temperature on the magnitude of these diurnal patterns. Maximum …

Fungal Biology And Agriculture: Revisiting The Field, O. Yarden, D. J. Ebbole, S. Freeman, R. J. Rodriguez, M. B. Dickman

Department of Plant Pathology: Faculty Publications

Plant pathology has made significant progress over the years, a process that involved overcoming a variety of conceptual and technological hurdles. Descriptive mycology and the advent of chemical plant-disease management have been followed by biochemical and physiological studies of fungi and their hosts. The later establishment of biochemical genetics along with the introduction of DNA-mediated transformation have set the stage for dissection of gene function and advances in our understanding of fungal cell biology and plant–fungus interactions. Currently, with the advent of high-throughput technologies, we have the capacity to acquire vast data sets that have direct relevance to the numerous …

Transcription Strategy In A Closterovirus: A Novel 5'-Proximal Controller Element Of Citrus Tristeza Virus Produces 5'- And 3'-Terminal Subgenomic Rnas And Differs From 3' Open Reading Frame Controller Elements, Siddarame Gowda, Maria A. Ayllon, Satyanarayana Tatineni, Moshe Bar-Joseph, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV) produces more than thirty 3'- or 5'-terminal subgenomic RNAs (sgRNAs) that accumulate to various extents during replication in protoplasts and plants. Among the most unusual species are two abundant populations of small 5'-terminal sgRNAs of approximately 800 nucleotides (nt) termed low-molecular-weight tristeza (LMT1 and LMT2) RNAs. Remarkably, CTV replicons with all 10 3' genes deleted produce only the larger LMT1 RNAs. These 5'-terminal positive-sense sgRNAs do not have corresponding negative strands and were hypothesized to be produced by premature termination during plus-strand genomic RNA synthesis. We characterized a cis-acting element that controls the production …

Evaluation Of Resistance Screening Methods For Sclerotinia Stem Rot Of Soybean And Dry Bean, Linda S. Kull, Tri D. Vuong, Kris S. Powers, Kent M. Eskridge, James R. Steadman, Glen L. Hartman

Department of Plant Pathology: Faculty Publications

Three methods to identify levels of resistance to Sclerotinia sclerotiorum in soybean (Glycine max) and dry bean (Phaseolus vulgaris) were compared using multiple data analyses. The three methods were mycelial plug inoculations of cotyledons, cut stems, and detached leaves. Six S. sclerotiorum isolates of known relative aggressiveness were inoculated on each of three soybean and dry bean cultivars with varied response to S. sclerotiorum. For soybean, all three inoculation methods accurately identified isolate aggressiveness irrespective of cultivar, but identification of susceptible and partially resistant soybean cultivars was influenced by isolate. For dry bean, the cotyledon and cut …

Greenhouse Gas Emissions And Soil Indicators Four Years After Manure And Compost Applications, Daniel Ginting, Anabayan Kessavalou, Bahman Eghball, John W. Doran

Department of Agronomy and Horticulture: Faculty Publications

Understanding how carbon, nitrogen, and key soil attributes affect gas emissions from soil is crucial for alleviating their undesirable residual effects that can linger for years after termination of manure and compost applications. This study was conducted to evaluate the emission of soil CO₂, N₂O, and CH₄ and soil C and N indicators four years after manure and compost application had stopped. Experimental plots were treated with annual synthetic N fertilizer (FRT), annual and biennial manure (MN1 and MN2, respectively), and compost (CP1 and CP2, respectively) from 1992 to 1995 based on removal of 151 …

Registration Of ‘Ne422t’ Winter Triticale, P. Stephen Baenziger, K. P. Vogel

Department of Agronomy and Horticulture: Faculty Publications

NE422T triticale (X Triticosecale Wittmack) (Reg. no CV-27, PI 629028) was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS. It was jointly released in 2001 by the developing institutions. NW422T was selected from the cross ‘Trical’/‘UB-UW26’ where Trical is most likely ‘Trical 100’ (a forage triticale developed by Resource Seed Inc., a subsidiary of Goldsmith Seed Company, Gilroy, CA) and UB-UW26 is an unknown winter triticale germplasm line given to the breeding program in the 1980s.The cross was made in 1990. The F₁ generation was grown in the greenhouse in 1990-1991. The F₂ and F …

Characterization Of Fro1, A Pea Ferric-Chelate Reductase Involved In Root Iron Acquisition, Brian M. Waters, Dale G. Blevins, David J. Eide

Department of Agronomy and Horticulture: Faculty Publications

To acquire iron, many plant species reduce soil Fe(III) to Fe(II) by Fe(III)-chelate reductases embedded in the plasma membrane of root epidermal cells. The reduced product is then taken up by Fe(II) transporter proteins. These activities are induced under Fe deficiency. We describe here the FRO₁ gene from pea (Pisum sativum), which encodes an Fe(III)-chelate reductase. Consistent with this proposed role, FRO₁ shows similarity to other oxidoreductase proteins, and expression of FRO₁ in yeast conferred increased Fe(III)-chelate reductase activity. Furthermore, FRO₁ mRNA levels in plants correlated with Fe(III)-chelate reductase activity. Sites of FRO_{1 …}

Accumulation Of Microbial Biomass Within Particulate Organic Matter Of Aging Golf Greens, Mine Kerek, Rhae A. Drijber, William L. Powers, Robert C. Shearman, Roch E. Gaussoin, Anne Streich

Department of Agronomy and Horticulture: Faculty Publications

Microbial biomass (MB) is a key variable controlling soil organic matter dynamics in soil. Currently, there is little information on the amount and significance of MB in highly managed golf greens. Our objective was to determine the amount and distribution of MB within soil structural components of golf greens and its relationship to the location of organic substrates. During 1996, 47 greens were sampled from 12 golf courses within Nebraska (USA). Microbial biomass, determined as extractable lipid phosphate on field-moist soils, increased linearly with age of green (Y = 19.39 + 3.54x; r² = 0.87, P = 0.001). In …

Crop Updates 2002 - Weeds, Vanessa Stewart, Peter Newman, Glenn Adam, Andrew Blake, Natalie Lauritsen, Sally Peltzer, Paul Matson, Nerys Wilkins, David Minkey, Glen Riethmuller, Tim Cusack, Kathryn Steadman, Pippa Michael, Paul Blackwell, Dave Brindal, Michael Walsh, Wayne Parker, Clinton Revell, Giles Glasson, Dean Thomas, Alister Draper, Bill Roy, Marta Monjardin, David Pannell, Stephen Powles, Robert Barrett-Lennard, Martin Bent, Paul Neve, Art Diggle, Patrick Smith, Mechelle Owen, Abul Hashem, Christopher Preston, Tracey Gillam, Rick Llewellyn, Richard Quinlan, Aik Cheam, Siew Lee, Mike Clarke, David Nicholson, Harmoohinder S. Dhammu, Terry Piper, Chad Sayer, Ian Rose, Andrew Blake, Jerome Critch, Gordon R. Cumming, Sam Taylor, John Moore, Rosyln Jettner, Stuart Bee, Lionel Martin, Keith Devenish, Felicity Flugge, Amir Abadi, Duncan Peter, Stuart Mcalpine

Crop Updates

This session covers fifty eight papers from different authors:

1. INTRODUCTION Vanessa Stewart, DEPARTMENT OF AGRICULTURE

INTEGRATED WEED MANAGEMENT

IWM system studies / demonstration sites

2. Major outcomes from IWM demonstration sites, Alexandra Douglas Department of Agriculture

3. Integrated weed management: Katanning, Alexandra Douglas Department of Agriculture

4. Integrated weed management: Merredin, Vanessa Stewart Department of Agriculture

5. Long term resistance site: Get ryegrass numbers low and keep them low! Peter Newman and Glen Adams Department of Agriculture

6. Using pastures to manage ryegrass populations, Andrew Blake and Natalie Lauritsen Department of Agriculture

Weed biology and competition

7. …

Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker

Diana Pilson Publications

Herbivore damage is generally detrimental to plant fitness, and the evolutionary response of plant populations to damage can involve either increased resistance or increased tolerance. While characters that contribute to resistance, such as secondary chemicals and trichomes, are relatively well understood, characters that contribute to a plant’s ability to tolerate damage have received much less attention. Using Helianthus annuus (wild sunflower) and simulated damage of Haplorhynchites aeneus (head-clipping weevil) as a model system, we examined morphological characters and developmental processes that contribute to compensatory ability. We performed a factorial experiment that included three levels of damage (none, the first two, …

Selected Soybean Plant Introductions With Partial Resistance To Sclerotinia Sclerotiorum, D. D. Hoffman, B. W. Diers, G. L. Hartman, C. D. Nickell, R. L. Nelson, W. L. Pedersen, E. R. Cober, George L. Graef, J. R. Steadman, C. R. Grau, B. D. Nelson, L. E. Del Rio, T. Helms, T. Anderson, V. Poysa, University Of Guelph, W. C. Stienstra

Department of Plant Pathology: Faculty Publications

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and …

Greenhouse And Field Evaluation Of Biological Control Of Fusarium Head Blight On Durum Wheat, D. A. Schisler, N. I. Khan, Michael J. Boehm, P. J. Slininger

Department of Plant Pathology: Faculty Publications

Fusarium head blight (FHB) is a devastating disease that causes extensive yield and quality losses to wheat and barley. In durum wheat, the pathogen-produced toxin deoxynivalenol (DON) is retained in semolina at ~50%, and the causal agent of FHB, Gibberella zeae, has a strong adverse effect on pasta color. Two bacteria and two yeast strains with known efficacy against G. zeae on hexaploid wheats were produced in liquid culture and assayed on two cultivars of durum wheat in greenhouse bioassays. All antagonists reduced FHB severity on cultivar Renville, and three of the four reduced severity on cultivar Ben, with …

Fire Effects On Three Trophic Levels In A Central Arkansas Grassland, Laura Skelton, Amy Polk, Brenna C. Fitzgerald, Matthew D. Moran

Journal of the Arkansas Academy of Science

We studied the effect of a late growing-season fire on the plant and foliar arthropod communities in a naturally occurring grassland. In central Arkansas, these grasslands are common on south-facing slopes where shallow soils and hot/dry weather conditions during the summer cannot support the growth of a forest community. Patches of grassland were burned in the autumn (4 November, late growing season), often the time of natural fires in Arkansas, and compared to unburned areas. Fire increased the biomass of forbs and decreased the biomass of grasses, although overall biomass was not different between treatments. Among the foliar arthropods, herbivores …

The P23 Protein Of Citrus Tristeza Virus Controls Asymmetrical Rna Accumulation, Satyanarayana Tatineni, Siddarame Gowda, Maria A. Ayllon, Maria R. Albiach-Marti, Shailaja Rabindran, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, has a 19.3-kb positive-stranded RNA genome that is organized into 12 open reading frames (ORFs) with the 10 3' genes expressed via a nested set of nine or ten 3'-coterminal subgenomic mRNAs (sgRNAs). Relatively large amounts of negative-stranded RNAs complementary to both genomic and sgRNAs accumulate in infected cells. As is characteristic of RNA viruses, wild-type CTV produced more positive than negative strands, with the plus-to-minus ratios of genomic and sgRNAs estimated at 10 to 20:1 and 40 to 50:1, respectively. However, a mutant with all of the 3' genes …

Genetic Analysis Of Feed Quality And Seed Weight Of Sorghum Inbred Lines And Hybrids Using Analytical Methods And Nirs, C. Hicks, M. R. Tuinstra, Jeffrey F. Pedersen, F. E. Dowell, K. D. Kofoid

Department of Agronomy and Horticulture: Faculty Publications

Eight lines of grain sorghum and their F1 hybrids were evaluated for contents of crude protein (CP), fat (FAT), and starch (STA); protein digestibility (PD); and in vitro dry matter disappearance (IVDMD). The effect of seed weight (SW) on these traits and the potential use of near infrared reflectance spectroscopy (NIRS) to predict them also were investigated. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two largeseeded lines (PL-1 and Eastin1). The female lines included commonU.S. seed parent lines (Wheatland, Redlan, and SA3042). The lines and their hybrids were grown under dryland conditions at Kansas State …

Combinatorial Control Of Yeast Fet4 Gene Expression By Iron, Zinc, And Oxygen, Brian M. Waters, David J. Eide

Department of Agronomy and Horticulture: Faculty Publications

Acquisition of metals such as iron, copper, and zinc by the yeast Saccharomyces cerevisiae is tightly regulated. High affinity uptake systems are induced under metal-limiting conditions to maintain an adequate supply of these essential nutrients. Low affinity uptake systems function when their substrates are in greater supply. The FET₄ gene encodes a low affinity iron and copper uptake transporter. FET₄ expression is regulated by several environmental factors. In this report, we describe the molecular mechanisms underlying this regulation. First, we found that FET₄ expression is induced in iron-limited cells by the Aft1 iron-responsive transcriptional activator. Second, FET …

First Report Of Columbia Root Knot Nematode (Meloidogyne Chitwoodi) In Potato In Texas, A. L. Szalanski, P. G. Mullin, T. S. Harris, T. O. Powers

Department of Plant Pathology: Faculty Publications

Columbia root-knot nematode, Meloidogyne chitwoodi Golden et al. (1) was identified from potatoes, Solanum tuberosum L., collected from Dallam County, Texas in October 2000. Seed potatoes are the most likely source for this introduction. This nematode is currently found infecting potatoes grown in California, Colorado, Idaho, New Mexico, Nevada, Oregon, Utah, and Washington. Some countries prohibit import of both seed and table stock potatoes originating in states known to harbor M. chitwoodi. Lesions on the potatoes had discrete brown coloration with white central spots in the outer 1 cm of the tuber flesh. Female nematode densities averaged 3 per square …

Crop Updates 2001 - Grower Booklet, Graeme Robertson, Jatinderpal Bathal, Cameron Weeks, Kithsiri Jayasena, Rob Loughman, Bill Bowden, Chris Gazey, Ross Brennan, Ian Foster, Q. Knight, Ross Kingwell, S. B. Sharma, S. Kelly, Glen Mcdonald, Kevin Young, Blakely Paynter, Keith Devenish, Abul Hashem, Nerys Wilkins, Terry Piper, Sally Peltzer, Clinton K. Revell, Candy Hudson, Ian Rose, Alexandra Wallace, Paul Blackwell, Miles Obst, David Bowran, Bevan J. Buirchell, Moin U. Salam, Art Diggle, Geoff J. Thomas, Mark W. Sweetingham, Bill O'Neill, Rafiul Alam, Glen Riethmuller, Greg Hamilton, Paul Carmody, G. Walton, B. Macleod, Mark Seymour, Harmohinder Dhammu, D. Nicholson, M. D'Antuono

Crop Updates

1. Strategies for leaf disease management in wheat, Jatinderpal Bhathal¹, Cameron Weeks², Kith Jayasena¹ and Robert Loughman¹, 1Agriculture Western Australia. 2Mingenew-Irwin Group Inc.

2. Burn stubble windrows: to diagnose soil fertility problems, Bill Bowden, Chris Gazey and Ross Brennan, Agriculture Western Australia

3. Rainfall – what happened in 2000 and the prospects for 2001, Ian Foster, Agriculture Western Australia

4. Strategies for leaf disease management in malting barley, K. Jayasena1, Q. Knight2 and R. Loughman1, 1Agriculture Western Australia, 2IAMA Agribusiness

5. Planning your cropping program in season 2001, Dr …

Virulence Of Puccinia Triticina On Wheat In Nebraska During 1997 And 1998, J. E. Watkins, J. Schimelfenig, P. Stephen Baenziger, Kent M. Eskridge

Department of Plant Pathology: Faculty Publications

Urediniospore isolates of Puccinia triticina were obtained from wheat leaf collections made in three wheat-growing regions in Nebraska in 1997 and in four regions in 1998. Using 16 Thatcher lines that are near-isogenic for leaf rust resistance, 17 virulence phenotypes were found among 121 single uredinial isolates in 1997, and 42 virulence phenotypes were found among 178 isolates in 1998. The most prevalent phenotype in 1997 was MDRR (virulent on Lr1, 3, 3ka, 10, 11, 18, 23, 24, and 30). In 1998, virulence phenotypes MDRR and MDRM (virulent on Lr1, 3, 3ka, 10, 11, 23, 24, and 30 …

Bacillus Species For Reducing Fusarium Head Blight In Cereals, David A. Schisler, Naseem I. Khan, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Microbial antagonists that will suppress Fusarium head blight (head scab) in cereals, particularly in wheat and barley have been identified. Two superior antagonists include NRRL B-30210 and NRRL B-30211.

Selection And Evaluation Of Microorganisms For Biocontrol Of Fusarium Head Blight Of Wheat Incited By Gibberella Zeae, N. I. Khan, D. A. Schisler, Michael J. Boehm, P. J. Slininger, R. J. Bothast

Department of Plant Pathology: Faculty Publications

Gibberella zeae incites Fusarium head blight (FHB), a devastating disease that causes extensive yield and quality losses to wheat and barley. Of over 700 microbial strains obtained from wheat anthers, 54 were able to utilize tartaric acid as a carbon source when the compound was supplied as choline bitartrate in liquid culture. Four tartaric acid–utilizing and three nonutilizing strains reduced FHB in initial tests and were selected for further assays. Antagonists were effective against three different isolates of G. zeae when single wheat florets were inoculated with pathogen and antagonist inoculum. All seven antagonists increased 100-kernel weight when applied simultaneously …

Genetic Analysis Of Kafirins And Their Phenotypic Correlations With Feed Quality Traits, In Vitro Digestibility, And Seed Weight In Grain Sorghum, C. Hicks, S. R. Bean, G. L. Lookhart, Jeffrey F. Pedersen, K. D. Kofoid, M. R. Tuinstra

Department of Agronomy and Horticulture: Faculty Publications

Twenty-three entries of grain sorghum (Sorghum bicolor (L.) Moench), including eight inbred lines (five males and three females) and 15 hybrids, were evaluated to determine the proportion of γ, αII, and β-αI-kafirins and their association with contents of crude protein, fat, and starch; protein digestibility; in vitro dry matter disappearance; and seed weight. The male lines included three normal-seeded lines (TX2737, TX435, and P954063) and two large-seeded lines (Eastin1 and PL-1). Female lines consisted of three common U.S. seed parent lines (Wheatland, Redlan, and SA3042). The lines and their hybrids were grown under dryland conditions at two locations in …

Seed Physiology, Production & Technology: Germination, Emergence, And Yield Of 20 Plant-Color, Seed-Color Near-Isogenic Lines Of Grain Sorghum, Jeffrey F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

Although there is growing demand for sorghum [Sorghum bicolor (L.) Moench] with white seed and tan plant color, there is limited information on the overall agronomic fitness of sorghum with these characters. A set of experiments was conducted to evaluate the combined effects of plant color and seed color on sorghum germination, emergence, and agronomic performance. Twenty near-isogenic lines with red seed/tan plant (RT), red seed/purple plant (RP), white seed/ tan plant (WT), white seed/purple plant (WP) phenotypes were tested under field and laboratory conditions. Plant color X seed color interactions were not significant. Purple plant color phenotypes had higher …

The Aspergillus Nidulans Snt Genes Are Required For The Regulation Of Septum Formation And Cell Cycle Checkpoints, Peter R. Kraus, Steven D. Harris

Department of Plant Pathology: Faculty Publications

In Aspergillus nidulans, germinating conidia undergo multiple rounds of nuclear division before forming a septum. Previous genetic results suggest that the ability to separate nuclear division and septum formation depends upon a threshold level of activity of the cyclin-dependent kinase NIMXcdk1. Mutations in nimX and nimT, the gene encoding the NIMXcdk1-activating phosphatase, have revealed that Tyr-15 phosphorylation is important for determining the timing of the formation of the first septum. Here, we describe a screen for suppressors of nimT23 (snt), designed to identify additional components of the pathway regulating septum formation. We show that a subset …

Age-Related Resistance In Bell Pepper To Cucumber Mosaic Virus , Hernan Garcia-Ruiz, John F. Murphy

Department of Plant Pathology: Faculty Publications

We demonstrated the occurrence of mature plant resistance in Capsicum annuum 'Early Calwonder' to Cucumber mosaic virus (CMV) under greenhouse conditions. When Early Cal wonder plants were sown at 10 day intervals and transplanted to 10-cm square pots, three distinct plant sizes were identified that were designated small, medium and large. Trials conducted during each season showed that CMV accumulated in inoculated leaves of all plants of each size category. All small plants (with the exception of the winter trial) developed a systemic infection that included accumulation of CMV in uninoculated leaves and severe systemic symptoms. Medium plants had a …

Genomic Regions That Underlie Soybean Seed Isoflavone Content, K. Meksem, V. N. Njiti, W. J. Banz, M. J. Iqbal, My. M. Kassem, David L. Hyten, J. Yuang, T. A. Winters, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

Soy products contain isoflavones (genistein, daidzein, and glycitein)that display biological effects when ingested by humans and animals, these effects are species, dose and age dependent. Therefore, the content and quality of isoflavones in soybeans is a key to their biological effect. Our objective was to identify loci that underlie isoflavone content in soybean seeds. The study involved 100 recombinant inbred lines (RIL)fr om the cross of ‘Essex’ by ‘Forrest,’ two cultivars that contrast for isoflavone content. Isoflavone content of seeds fromeach RIL was determined by high performance liquid chromatography (HPLC). The distribution of isoflavone content was continuous and unimodal. The …

Sequences Of Citrus Tristeza Virus Separated In Time And Space Are Essentially Identical, Maria R. Albiach-Marti, Munir Mawassi, Siddarame Gowda, Satyanarayana Tatineni, Mark E. Hilf, Savita Shanker, Ernesto C. Almira, Maria C. Vives, Carmelo Lopez, Jose Guerri, Ricardo Flores, Pedro Moreno, Steve M. Garnsey, William O. Dawson

Department of Plant Pathology: Faculty Publications

The first Citrus tristeza virus (CTV) genomes completely sequenced (19.3-kb positive-sense RNA), from four biologically distinct isolates, are unexpectedly divergent in nucleotide sequence (up to 60% divergence). Understanding of whether these large sequence differences resulted from recent evolution is important for the design of disease management strategies, particularly the use of genetically engineered mild (essentially symptomless)-strain cross protection and RNA-mediated transgenic resistance. The complete sequence of a mild isolate (T30) which has been endemic in Florida for about a century was found to be nearly identical to the genomic sequence of a mild isolate (T385) from Spain. Moreover, samples of …

Utility Of The Mitochondrial Cytochrome Oxidase Ii Gene For Resolving Relationships Among Black Flies (Diptera: Simuliidae), K. P. Pruess, B. J. Adams, T. J. Parsons, X. Zhu, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

The complete mitochondrial cytochrome oxidase II gene was sequenced from 17 black flies, representing 13 putative species, and used to infer phylogenetic relationships. A midge (Paratanytarsus sp.) and three mosquitoes (Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus) were used as outgroup taxa. All outgroup taxa were highly divergent from black flies. Phylogenetic trees based on weighted parsimony (a priori and a posteriori), maximum likelihood, and neighbor-joining (log-determinant distances) differed topologically, with deeper nodes being the least well-supported. All analyses supported current classification into species groups but relationships among those groups were poorly resolved. The majority of phylogenetic …