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Full-Text Articles in Physical Sciences and Mathematics
Evaluation Of Blight Resistance In Chestnut F2 Half-Sibling And Full-Sibling Families Via Small Stem Assay, Kevin Gentner
Evaluation Of Blight Resistance In Chestnut F2 Half-Sibling And Full-Sibling Families Via Small Stem Assay, Kevin Gentner
Honors Theses
In 1904, Cryphonectria parasitica, the causal agent for chestnut blight, was imported into North America on chestnut nursery stock from China. Fifty-five years later, nearly all full-grown wild American chestnut trees (Castanea dentata) were dead. A century of work has been put into restoring the American chestnut to its rightful place among the forest canopy. Since the 1980s, The American Chestnut Foundation has pursued backcross breeding to introgress blight resistance into C. dentata from the resistant Chinese species (C. mollissima), and has used progeny testing to make predictions about parental resistance in B3F2 chestnuts. We performed a small stem assay …
Conservation And Collection Of Castanea Dentata Germplasm In The South, Trent Deason
Conservation And Collection Of Castanea Dentata Germplasm In The South, Trent Deason
Honors Theses
The American chestnut, Castanea dentata, has been devastated by the exotic invasive pathogens Cryphonectria parasitica and Phytophthora cinnamomi to which it has no resistance. The American Chestnut Foundation (TACF) has developed an interspecific backcross breeding program to introgress disease resistance from Asian chestnut species, primarily Castanea mollissima, into C. dentata hybrid populations. The genetic base of this program can be expanded by utilizing vegetative propagation through grafting in order to collect and conserve American chestnut individuals not amenable to traditional breeding. As the majority of the surviving American chestnuts are confined to the understory, they are shaded out by the …
Implementing Early Screening Methods To Detect Resistance To Phytophthora Cinnamomi In Backcross Chinese-American Chestnut Hybrids, Kirsten Hein
Honors Theses
Phytophthora root rot (PRR), caused by the oomycete Phytophthora cinnamomi Rands., is one of the two greatest obstacles to survival of American chestnut (Castanea dentata Borkh.). The other is chestnut blight, caused by the ascomycete Cryphonectria parasitica (Murr.) Barr. Developing early and reliable PRR screening methods can facilitate the efficient introgression of PRR resistance from Chinese chestnut (C. mollissima Blume.) into the populations of potentially chestnut blight resistant trees currently under development by The American Chestnut Foundation (TACF). This study tests the efficacy of a method for early identification of PRR-resistant hybrid chestnuts in a greenhouse/nursery setting. The chestnut blight …
Measuring Phytophthora Resistance Phenotypes In Segregating Testcross Families Of Hybrid American Chestnut Trees, Anna C. Robinson
Measuring Phytophthora Resistance Phenotypes In Segregating Testcross Families Of Hybrid American Chestnut Trees, Anna C. Robinson
Honors Theses
Phytophthora root rot (PRR), caused by the oomycete Phytophthora cinnamomi Rands, is a formidable obstacle to the restoration of Castanea dentata Marsh. commonly known as the American chestnut. Genetic resistance to PRR has been observed in Asian species of chestnut including C. mollissima Blume, and in interspecific hybrids between C. mollissima and C. dentata. We hypothesized that root rot resistance alleles would segregate in a 1:1 ratio within progeny of crosses between PRR resistant F1 hybrids and PRR-susceptible American chestnut trees (first-backcrosses), and that PRR resistance could be successfully passed down to all families of first-backcross hybrids. To test these …
A Vascular Flora Of Bendabout Farm, Bradley County, Tennessee And Survey Of Native Castanea Dentata (Marsh) Borkh. (Fagaceae, American Chestnut), Amelia Paige Harris
A Vascular Flora Of Bendabout Farm, Bradley County, Tennessee And Survey Of Native Castanea Dentata (Marsh) Borkh. (Fagaceae, American Chestnut), Amelia Paige Harris
Masters Theses and Doctoral Dissertations
The primary goal of this study was to inventory the flora of Bendabout Farm, a 1,467 ha privately-owned farm in Bradley County, Tennessee. A second goal was to conduct a census of the population and distribution of surviving Castanea dentata (Marsh) Borkh. (American chestnut) within the study area. Both natural/semi-natural and altered habitats were described during initial habitat characterization. The study recorded 433 species from 261 genera in 106 families. The study documented 250 new records for Bradley County. Special Concern Species, Panax quinqu efolius L., was vouchered, as were 68 non-native species. C. dentata were located using the sweep …
Chestnut (Castanea Spp.) Cultivar Evaluation For Commercial Chestnut Production In Hamilton County, Tennessee, Ana Maria Metaxas
Chestnut (Castanea Spp.) Cultivar Evaluation For Commercial Chestnut Production In Hamilton County, Tennessee, Ana Maria Metaxas
Masters Theses and Doctoral Dissertations
Chestnut cultivars were evaluated for their commercial applicability under the environmental conditions in Hamilton County, TN at 35° 13ꞌ 45ꞌꞌ N 85° 00ꞌ 03.97ꞌꞌ W elevation 230 meters. In 2003 and 2004, 534 trees were planted, representing 64 different cultivars, varieties, and species. Twenty trees from each of 20 different cultivars were planted as five-tree plots in a randomized complete block design in four blocks of 100 trees each, amounting to 400 trees. The remaining 44 chestnut cultivars, varieties, and species served as a germplasm collection. These were planted in guard rows surrounding the four blocks in completely randomized, single-tree …
Not Extinct: A Year In The Life Of The American Chesnut, Kristen Julina Stanfill
Not Extinct: A Year In The Life Of The American Chesnut, Kristen Julina Stanfill
Honors Theses
After the widespread infection of the American chestnut tree (Castanea dentata) due to the fungus Cryphonectria parasitica the species was nearly brought to extinction and now merely exists as stump sprouts. Since the fungus infects the bark of the tree but not the root systems new shoots are able to emerge and grow before once again being girdled by the fungus. Cryphonectria parasitica is believed to have been brought to America on Asian species of chestnut which possess resistance to the blight caused by the fungus. It is the plan of the American Chestnut Foundation (TACF) to integrate the genes …
The Effect Of Phosphite On Mycorrhiza Formation In American Chestnut (Castanea Dentata), Matthew T. Perkins
The Effect Of Phosphite On Mycorrhiza Formation In American Chestnut (Castanea Dentata), Matthew T. Perkins
Honors Theses
One of the primary hindrances to Castanea dentata restoration in the Southeast is the root rot disease caused by the fungus-like microorganism Phytophthora cinnamomi. Root rot can be combated by the application of mono- and di-potassium salts of phosphorous acid, which are marketed as phosphite fungicides. Despite its value in preventing infection by P. cinnamomi it is also thought that phosphite may impede root colonization by beneficial, ectomycorrhizal fungi. I hypothesized that plants given a routine application of phosphite will display fewer mycorrhizas in the root tips than those plants that were not treated with potassium phosphite. Therefore I attempted …
An Oral History Of The American Chestnut In Southern Appalachia, Bethany N. Baxter
An Oral History Of The American Chestnut In Southern Appalachia, Bethany N. Baxter
Masters Theses and Doctoral Dissertations
This oral history research explored and examined the experences and memories of people who lived in the Southern Appalachian region during the years preceding and following the chestnut blight pandemic. The project examined experiences from an environmental history perspective, addressing the economic and cultural significance of chestnut pre and post blight, and attitudes and feelings concerning American chestnut restoration efforts. The American Chestnut Oral History Collection includes forty-five interviews, recorded between May and December 2008. Twenty-seven of them were recorded with people who have memories of the importance of American chestnut in southern Appalachia. These interviews were conducted across Kentucky, …
Matrix Geochemistry And Phytophthora Occurrence On Reforested Mine Lands In Appalachia, Kathryn M. Ward
Matrix Geochemistry And Phytophthora Occurrence On Reforested Mine Lands In Appalachia, Kathryn M. Ward
University of Kentucky Master's Theses
At the Bent Mountain surface mine, Pike County, Kentucky, a study has been ongoing since 2005 to assess the influence of various types of loose-graded mine spoils on water quality and forest establishment. Six research plots consist of two replicates of brown weathered sandstone, gray unweathered sandstone, and mixed brown sandstone, gray sandstone, and shale that were emplaced according to Forestry Reclamation Approach criteria. A series of analyses was initiated in 2007 to examine influence of spoil matrix composition on sulfate and carbonate geochemistry of infiltrated waters, as well as to investigate the occurrence of Phytophthora, a group of …
The Phylogeography Of North American Chestnuts And Chinquapins (Castanea Mill., Fagaceae), Meagan A. Binkley
The Phylogeography Of North American Chestnuts And Chinquapins (Castanea Mill., Fagaceae), Meagan A. Binkley
Masters Theses and Doctoral Dissertations
North American Castanea Mill. (Fagaceae) consists of three morphologically variable species: Castanea dentata, Castanea pumila and Castanea ozarkensis. Taxonomy of these species has been complicated by intermediate morphology, similarity in growth habit, and putative naturally occurring hybridization where species' ranges overlap in the southeast. The main goals of the present study were to: 1) determine if genetics reflect the morphological variation observed in southeastern populations of North American Castanea, 2) explore the extent of cpDNA haplotype sharing among these taxa, and 3) map haplotype distribution in relation to morphotaxa. Finally, I wanted to use the information obtained from these analyses …
Conservation Of Castanea Dentata Genetic Resources Of The Southeastern United States, Mark Thomas Alexander
Conservation Of Castanea Dentata Genetic Resources Of The Southeastern United States, Mark Thomas Alexander
Masters Theses and Doctoral Dissertations
The ongoing effort by the American Chestnut Foundation to breed and reintroduce a blight resistant, locally adapted variety of American chestnut (Castanea dentata) requires a broad genetic base. To ensure adequate genetic diversity, genetic resources must be collected from throughout the native range of the species. Finding and breeding surviving C. dentata stump sprouts is problematic due to the relatively short life span of blooming stems and their often remote forest habitat. To facilitate more efficient location of surviving trees in the southeastern U.S., we used a Geographic Information System (GIS) to overlay soil, topography, and satellite imagery for the …
Pollen Study In Castanea Dentata And C. Mollissima, Christine Johnson Bock
Pollen Study In Castanea Dentata And C. Mollissima, Christine Johnson Bock
Masters Theses and Doctoral Dissertations
The purpose of this research was to see if Castanea dentata (Marshall) Borkhausen and C. mollissima Blume are anemophilous or entomophilous and to investigate the direction and distance of C. dentata pollen dispersal. The study of C. dentata pollen dispersal patterns was set up at an isolated orchard in Cleveland, Tennessee. Pollen collectors were placed at 13 locations in an array 15.2, 30.4, 46 and 61 meters north, northeast and east from the northeast corner of the orchard with one collector in the orchard itself. Pollen counts averaged significantly higher at the orchard than at sites 15.2, 30.4, 46 and …
Host-Pathogen Interactions In A Segregating Population Of Bc2f2 Hybrid Castanea Dentata And Other Chesnut Hybirds After Exposure To Hypovirus-Containing And Hypvirus-Free Strains Of Cryphonectria Parasitica, Stephen Henry Alexander
Host-Pathogen Interactions In A Segregating Population Of Bc2f2 Hybrid Castanea Dentata And Other Chesnut Hybirds After Exposure To Hypovirus-Containing And Hypvirus-Free Strains Of Cryphonectria Parasitica, Stephen Henry Alexander
Masters Theses and Doctoral Dissertations
An F2 population of second backcross interspecific hybrid chestnut trees (BC2F2) and the progeny of the Chattanooga Chestnut Tree Project (CCTP) breeding program were exposed to three isogenic strains of Cryphonectria parasitica. Strain Ep155 (virus-free) was used to screen the 4- 7 year old chestnut trees for resistance to chestnut blight disease. Two virus-containing, hypovirulent strains, Ep155(CHV1-Euro7) and Ep155(CHV1-Ep713), were used to investigate interactions of host disease resistance and expression ofhypovirulence. The BC2F2 population varied from highly susceptible to highly resistant, as measured by Ep155 (virus-free) canker length at 95 days. Disease resistance in the CCTP population varied from highly …
Conversion Of Virulent Cryphonectria Parasitica From The Lula Lake Land Trust To Hypovirulent Strains, Pearl Hwang
Conversion Of Virulent Cryphonectria Parasitica From The Lula Lake Land Trust To Hypovirulent Strains, Pearl Hwang
Honors Theses
For almost a century, the fungus, Cryphonectria parasitica has existed in the United States as a wound parasite to American chestnut (Castanea dentata) trees. However, hypovirulence, evidence of spontaneous healing in Italy and Michigan, has given the American chestnut trees hope to one day be restored into its natural range. Viruses were the cause of such spontaneous healings. My hypothesis was that a viruscontaining hypovirulent strain of C. parasitica (in a brown background) would share alleles that control anastomoses with the local virulent strains, so a virus that causes hypovirulence could be transmitted into local virulent strains in vitro. Fifty …