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Theses/Dissertations

2008

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Articles 1 - 12 of 12

Full-Text Articles in Agronomy and Crop Sciences

Growing Wild: Crested Wheatgrass And The Landscape Of Belonging, Lafe Gerald Conner Dec 2008

Growing Wild: Crested Wheatgrass And The Landscape Of Belonging, Lafe Gerald Conner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crested wheatgrass arrived in North America at the turn of the twentieth century through the foreign plant exploration missions sponsored by the United States Department of Agriculture. During the first two decades of the new century, scientists tested the grass at agricultural experiment stations. They determined it was useful for grazing and particularly valuable because it could grow in drought conditions with little or no care and would continue to produce high quality feed even after several years of heavy use. Beginning in the 1930s federally sponsored land utilization and agricultural adjustment programs sponsored the use of crested wheatgrass for …

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Ethylene Synthesis And Sensitivity In Crop Plants, Joseph F. Romagnano Dec 2008

Ethylene Synthesis And Sensitivity In Crop Plants, Joseph F. Romagnano

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The gaseous plant hormone ethylene is a small molecule that regulates developmental change. Research was conducted in three areas: sensitivity, synthesis, and alterations to synthesis. Vegetative pea plants were more sensitive than radish plants to atmospheric ethylene. Light intensity did not affect ethylene sensitivity. Ethylene synthesis rates were measured for unstressed cotton, corn, soybean, and tomato plants. The per-plant ethylene synthesis rate ranged from 0.1-80 pmol plant-1 s-1. However, when normalized to net photosynthetic rate, this range was 1-4 µmol of ethylene synthesis per mol of CO2 uptake. Diurnal cycles in ethylene synthesis were present in …

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Biology And Ecology Of Palmer Amaranth (Amaranthus Palmeri), Prashant Jha Dec 2008

Biology And Ecology Of Palmer Amaranth (Amaranthus Palmeri), Prashant Jha

All Dissertations

Palmer amaranth (Amaranthus palmeri S. Wats.) is a troublesome weed of crops in southeastern United States. This research highlights studies on the biology and ecology of Palmer amaranth. Following dispersal in fall, Palmer amaranth seeds require high mean temperatures of 25 to 40 C for germination, which is not likely to occur in South Carolina until the following spring. With dormancy reduction over winter, seeds can germinate at high temperatures (≥25 C) and thermal amplitudes of 15 C during late spring (May) in the presence of light. A majority (>90%) of the non-dormant population in the soil seedbank emerge …

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Variable Approaches Investigating Light Quality And Quantity Impacts On Warm- And Cool-Season Turfgrasses, Christian Baldwin May 2008

Variable Approaches Investigating Light Quality And Quantity Impacts On Warm- And Cool-Season Turfgrasses, Christian Baldwin

All Dissertations

Bermudagrass (Cynodon ssp.) is the most popular warm-season turfgrass used in warm climatic regions of the world due its recuperative ability, high traffic tolerance, heat tolerance, and relative drought and salt tolerance. However, shade is a microenvironment in which bermudagrass performs poorly. Morphological limitations, such as reduced lateral stem growth and overall reduction of carbohydrate synthesis contribute to bermudagrass, a C4 plant, decline under shade. Therefore, primary objectives of this dissertation were to determine the genetic diversity of bermudagrasses grown in full-sunlight and shade, impacts of shade and cultural practices on bermudagrass spring transition, management recommendations to enhance bermudagrass …

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In Vitro And In Vivo Techniques For Screening New Natural Product-Based Fungicides For Control Of Strawberry Anthracnose, Maritza Abril May 2008

In Vitro And In Vivo Techniques For Screening New Natural Product-Based Fungicides For Control Of Strawberry Anthracnose, Maritza Abril

Dissertations

Seven plant pathogenic fungi (Botrytis cinerea, Colletotrichum acutatum, C. fragariae, C. gloeosporioides, Fusarium oxysporum, Phomopsis obscurans, and P. viticola) valuable in screening fungicide efficacy were tested. Optimal and reproducible conditions for germination of these selected fungi were established by incorporating Roswell Park Memorial Institute 1640 (RPMI) as a medium of known composition and washing conidia to remove innate germination inhibitors. This step reduced average fungal germination times between 3.5 h and 21.2 h. The natural product-based fungicide, sampangine, seven sampangine analogs (4-bromo-sampangine, 4-methoxysampangine, benzo[4,5]sampangine, liriodenine Mel AMC-XIII-103, onychine, cryptolepine, and liriodenine CDH-II-37), plus seven conventional fungicides (benomyl, captan, cyprodinil, fenbuconazole, …

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Origins Of The Y Genome In Elymus, Pungu Okito May 2008

Origins Of The Y Genome In Elymus, Pungu Okito

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Triticeae tribe DUMORTER in the grass family (Poaceae) includes the most important cereal crops such as wheat, barley, and rye. They are also economically important forage grasses. Elymus is the largest and most complex genus with approximately 150 species occurring worldwide. Asia is an important centre for the origin and diversity of perennial species in the Triticeae tribe, and more than half of the Elymus are known to occur in the Asia. Cytologically, Elymus species have a genomic formula of StH, StP, StY, StStY, StHY, StPY, and StWY. About 40% of Elymus …

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Efecto De Los Microorganismos Eficientes Sobre La Calidad Del Ensilaje De Maíz Y Su Utilización En Lechería Tropical, María Antonia Londoño Gutiérrez Apr 2008

Efecto De Los Microorganismos Eficientes Sobre La Calidad Del Ensilaje De Maíz Y Su Utilización En Lechería Tropical, María Antonia Londoño Gutiérrez

Zootecnia

Este trabajo se realizó con objetivo de analizar el efecto de los microorganismos eficientes EM sobre el ensilaje de maíz como suplemento en lechería tropical. Este trabajo se desarrolló en dos fases, laboratorio con microsilos y de campo. Para analizar los cambios composicionales del ensilaje se utilizó la metodología de micrósilos y se evaluaron los cambios en cuanto a proteína cruda, proteína soluble, nitrógeno no proteico, fibra en detergente ácida y fibra en detergente neutra. En la fase de campo se utilizaron nueve vacas guzolando, en un sistema de pastoreo semi-intensivo con pasto Estrella (Cynodon nlemfluensis), que se dividieron en …

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Ethylene Production As An Indicator Of Stress Conditions In Hydroponically-Grown Strawberries, Justin Donald Hogan Jan 2008

Ethylene Production As An Indicator Of Stress Conditions In Hydroponically-Grown Strawberries, Justin Donald Hogan

Theses, Dissertations and Capstones

With the worldwide phaseout of methyl bromide, the use of hydroponic systems has increased as an economic alternative for the growth of many horticulturally-important crops, including strawberries. In this study, the effect of hydroponics on strawberry plant physiology was examined by first measuring ethylene levels, a plant hormone known to increase due to stressful conditions, and plant growth and yield. Using a gas chromatograph, ethylene was measured from plants which showed that light and temperature have minimal effects, but placement of plants could have an effect on plant growth and yield. Next, the mechanism of ethylene production was examined by …

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Methodology And Assessment Of The Susceptibility Of Potato Genotypes To Phytophthora Erythrosetpica Causal Organism Of Pink Rot, Erica Fitzpatrick-Peabody Jan 2008

Methodology And Assessment Of The Susceptibility Of Potato Genotypes To Phytophthora Erythrosetpica Causal Organism Of Pink Rot, Erica Fitzpatrick-Peabody

Electronic Theses and Dissertations

Phytophthora erythroseptica Pethyb., causal organism of potato (Solanum tuberosum L.) pink rot is a soil-borne ubiquitous oomycete pathogen that can cause severe losses in both the field prior to harvest and during storage. The efficacy of the most effective fungicide, mefenoxam for control of P. erythroseptica is in jeopardy due to the widespread development of resistance in the US. Cultivar resistance may provide the best option for management of P. erythroseptica in the future. Recently published reports of cultivars susceptible to P. erythroseptica are based on evaluation techniques involving detached tubers and nontuber germplasm rather than field evaluations. Screening detached …

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Map-Based Cloning Of An Anthracnose Resistance Gene In Medicago Truncatula, Shengming Yang Jan 2008

Map-Based Cloning Of An Anthracnose Resistance Gene In Medicago Truncatula, Shengming Yang

University of Kentucky Doctoral Dissertations

Anthracnose, caused by the fungal pathogen Colletotrichum trifolii, is one of the most destructive diseases of alfalfa worldwide. Cloning and characterization of the host resistance (R) genes against the pathogen will improve our knowledge of molecular mechanisms underlying host resistance and facilitate the development of resistant alfalfa cultivars. However, the intractable genetic system of cultivated alfalfa, owing to its tetrasomic inheritance and outcrossing nature, limits the ability to carry out genetic analysis in alfalfa. Nonetheless, the model legume Medicago truncatula, a close relative of alfalfa, provides a surrogate for cloning the counterparts of many agronomically important genes in …

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Performance And Physiology Of Yearling Steers Grazing Toxic Tall Fescue As Influenced By Concentrate Feeding And Steroidal Implants, Jessica Meagan Carter Jan 2008

Performance And Physiology Of Yearling Steers Grazing Toxic Tall Fescue As Influenced By Concentrate Feeding And Steroidal Implants, Jessica Meagan Carter

University of Kentucky Master's Theses

Fescue toxicosis can produce negative effects on animal weight gain and physiology. Sixty-four steers were grazed on endophyte-infected (E+) KY-31 tall fescue for 77 days in 2007 and sixty steers grazed for 86 days in 2008 to evaluate interactions with implantation of steroidal implants and concentrate feeding on performance and physiology of yearling steers. Steers were stratified by body weight for assignment to six, 3.0-ha toxic tall fescue pastures. The main plot treatment of with or without pelleted soybean hulls (SBH) were randomly assigned to pastures. Pelleted SBH were group-fed to provide daily consumptions of 2.3 kg/steer/d (as fed). Sub-plot …

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Resistance Of Different Tomato Varieties (Lycopersicon Esculentum) To Late Blight (Phytophthora Infestans) In Laboratory Conditions At Uac Carmen Pampa, In The Province Of Nor Yungas, Department Of La Paz, Andrez Faustino Florez Paxi Jan 2008

Resistance Of Different Tomato Varieties (Lycopersicon Esculentum) To Late Blight (Phytophthora Infestans) In Laboratory Conditions At Uac Carmen Pampa, In The Province Of Nor Yungas, Department Of La Paz, Andrez Faustino Florez Paxi

Theses and Dissertations

In order to respond to the low economic and harvesting yields caused by diseases that attack the tomato, we considered using tomato varieties resistant to late blight (Phytophthora infestans) of tomato (Lycopersicon esculentum) and potato (Solanum tuberosum). The evaluation of the percentage of infestation was performed with tomato leaflets over a 168 hour period. The percentage of infestation was recorded every eight hours from the time of inoculation until maximum infestation was reached. The methodology applied was at random and included six treatments and five replications. The experiment consisted of collecting healthy leaflets from five improved varieties and one local …

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