Life Sciences Commons^™

A Genome Wide Association Study Of Heat Tolerance In Snap Bean (Phaseolus Vulgaris), Morgan Stone

All Theses

Bean production in the United States has decreased while the temperatures have been steadily increasing, reaching new highs each year. Heat stress is detrimental to common bean (also known as snap bean) production. Symptoms of heat stress include decrease in pollen viability, shriveling of pods, and pod abortion making them unmarketable. Pod production of 323 snap bean accessions from a large diversity panel was assessed in a randomized complete block design with field trials at two different times in the spring season. The results show a significant decrease in the number of pods produced per plant and weight of pods …

Rapid Leaf Senescence Symptoms Are Related To Carbohydrate Depletion In Cut Chrysanthemums, And Strategies For The Symptoms Reduction, Shara Ortiz Carvajal

All Theses

Chrysanthemum (Chrysanthemum ×morifolium) is the second-largest exported cut flower worldwide; however, some cultivars exhibit rapid leaf senescence during their first week of vase life. This phenomenon negatively impacts consumer perception of plant quality, and its cause has been unknown. Experiments were performed in Colombia on cut chrysanthemums shipped to the U.S. for vase-life evaluation. After 10 d, the severity of leaf senescence symptoms was recorded. Experiments examined the effect of flower form [disbud (one flower per stem) versus spray (5-10 flowers per stem)], the effect of time of harvest (A.M. versus P.M.), and sugar sources (dextrose, fructose, mannitol, and sucrose) …

Salinity In Propagation: Germination And Juvenile Acclimatization Of Wetland Halophytes Using Saline Irrigation, Morgan Tomlin

All Theses

The introduction of poor water quality into commercial nursery crop production is predicated on optimized methods that apply saline irrigation without compromising plant success and health. Halophytes have many mechanisms of salt tolerance; however, these are greatly tied to physiological and developmental maturity. Thus, evaluating salt tolerance of halophytic crops (Hibiscus moscheutos and Kosteletzkya virginica) during seed germination and juvenile phases of life may provide insight into the efficacy of integrating poor quality water in horticultural operations.

Four seed priming methods (hydropriming, proline priming, low concentration halopriming, and high concentration halopriming) were evaluated as pre-sowing techniques to ameliorate …

Evaluating The Effect Of Biochar Soil Amendments On Belonolaimus Longicaudatus Populations Damaging Bermudagrass In South Carolina, Malone Thomason

All Theses

Belonolaimus longicaudatus Rau, (1958) (sting nematode) is a prevalent plant-parasitic nematode found in association with Cynodon spp. (bermudagrass) in South Carolina (Ye et al., 2012). Due to the persistence of the pest, long-term management strategies are necessary. Applications of biochar and compost amendments have reduced nematodes in various crop systems, but research on turfgrass systems is limited. The objectives of the studies were to determine: (1) The effect of topdressing or soil incorporated biochar amendments on sting nematode populations, and (2) The effect of topdressing or soil incorporated amendments on turf quality. A field study was established to examine topdressings …

Meta-Analysis Of The Effects Of Endophytes And Their Secondary Metabolites On Herbivory From Insects, Derrick Taylor

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Endophyte-infected plants have reduced the level of herbivory. The defense to herbivory can vary due to the metabolites in the plant and the method of feeding from the pest. Secondary metabolites produced by the endophytes are mainly alkaloids. The associations between endophytes and some alkaloid groups are studied in greater detail. The lack of research of certain alkaloid groups ultimately means that some alkaloids had more data that could be analyzed. As a result, the alkaloid groups were not evenly represented in the meta-analysis. The meta-analysis analyzed the relative effectiveness of the metabolites or endophytes in each of the articles …

In Vitro Rooting Techniques In Prunus Spp. For Propagation And Disease Screening For Armillaria Root Rot (Arr) Resistance, John Lawson

All Theses

Prunus is a genus widely cultivated to produce edible fruit including almond (P. amygdalus), peach (P. persica (L.) Batsch), cherries (P. avium and P. cerasus), among others. The cultivation of Prunus is economically important for several regions of the United States and relies on appropriate cultivars and rootstocks that are adapted to a growing region. Encroaching plant pathogens are forcing breeders to use sexually compatible germplasm from related species for introgression of novel alleles that confer tolerance or resistance. This is especially true in the rootstock breeding where interspecific hybridization is often used …

Identifying Temporal Sensitivity Of Poinsettia Flowering To High Temperatures, Paul Millar

All Theses

High temperatures can cause delayed flowering in poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch), a phenomenon known in the industry as heat delay. The poinsettia wholesale market is concentrated to a relatively brief period from early-November through early-December putting growers at risk to heat delay. This problem is compounded by the unusual weather patterns created by climate change. The objective of this thesis was to identify periods in which poinsettia flowering is sensitive to high temperatures. First, the weeks within the growing season when the plants were sensitive to high temperatures were identified (Chpt. 2). Then within those sensitive weeks, …

The Influence Of Water Stress And Rootstocks On Nutrient Uptake And Gas Exchange Of Young Peach Trees, Naif Alshammari

All Theses

Young peach trees are often rainfed in the southeastern U.S. and periods of dry weather can cause tree water deficit that can be detrimental to orchard productivity. There is a lack of understanding of the influence of water regimes and rootstocks on the nutritional status and gas exchange of the peach tree. Most peach growers in Southeastern United States do not irrigate their young peach trees because they do not produce fruit until the third leaf. In this region, peach growers use Guardian as a rootstock, although MP-29 is also interesting for growers with orchards that have Armillaria root rot …

Utility Of Anaerobic Soil Disinfestation For Weed And Disease Management In Solanaceous Vegetable Crops, Gursewak Singh

All Theses

Managing weeds is one of the most challenging aspects of growing specialty crops. Weed control options are limited for specialty crops due to absence of effective herbicide options. The limited current herbicide options risk carryover and damage to subsequent crops. Bacterial wilt is another problem causing significant yield losses in southeast vegetable production. After the termination of methyl bromide due to health and environmental concerns, several other chemical fumigants gained interest, including 1,3-dichloropropene, chloropicrin and metam sodium/potassium. While less toxic to the environment than methyl bromide, these fumigants pose carcinogenic and mutagenic threats. Alternative weed control and diseases management tactics …

Magnolia : Polyploidy, Genome Size, And Refinement Of Protocols For Micropropagation, James Parris

All Theses

The genus Magnolia includes over 250 species that range in ploidy level from diploid to hexaploid. Although there is basic information on ploidy levels of various species, sampling is limited with specific cultivars and hybrids. The objective of this research was to determine relative genome sizes and relationships to ploidy levels among a diverse collection of species, hybrids, and cultivars using flow cytometry. Nuclei were extracted, stained with 4’, 6–diamidino–2–phenylindole (DAPI), and analyzed using a flow cytometer. Relative genome sizes were determined using Pisum sativum as the reference genome. Genome size was calibrated with ploidy level for species with documented …

Effects Of Temperature, Light And Plant Growth Regulators On Fuel-Efficient Poinsettia Production, Francis Odula

All Theses

Fuel-efficient poinsettia production has become an important topic in recent years due to increased fuel costs while wholesale prices have remained relatively unchanged. Fuel-efficient production results in energy saving, reduces costs associated with production and improves profitability of the poinsettia crop. Experiments were carried out to determine the effects of Fascination (a plant growth regulator), production temperature, light, and cold pre-harvest temperature on bract expansion, cyathia development, and retention for fuel-efficient poinsettia production.
The first experiment (Chapter 2) examined the effects of the plant growth regulator Fascination on bract expansion of poinsettias grown at relatively cool production temperatures. Poinsettia, (Euphorbia …

Simultaneous Optimization Of Macronutrient Factors In Plant Tissue Culture Using Turmeric (Curcuma Longa L.) As A Model, Sean Halloran

All Theses

Murashige and Skoog 1962 performed one-factor-at-a-time (OFAT) experimentation in order to regenerate tobacco callus on semi-solid agar medium. This work became an established medium for tissue culture micropropagation and experimentation. Micropropagation is done in niche markets with herbaceous perennials, among other crops, and the optimization of various inputs to produce maximal responses is a necessary step towards process development. This current study of macronutrient factors simultaneously altered media volume, amount of tissue (plants per vessel), sucrose, nitrogen (as NO3- and NH4+ ions), and K+ in a d-optimal design space with only 55 experimental units (including 5 true replicates). The first …

Response Of Warm Season Turfgrasses To Reduced Light Environments, Jeffrey Atkinson

All Theses

Shade or low light tolerance is an increasingly important issue to turf managers as they are often expected to grow turf in less than ideal agronomic conditions. As permanent structures such as residential buildings add to already problematic shade caused by trees, and other barriers, new solutions are needed to help turf managers provide acceptable turf conditions. The plant growth regulator trinexapac-ethyl (TE) can lessen negative responses of turfgrass to shade.
Two experiments were conducted during the summers of 2008 and 2009 to evaluate various grasses under a reduced light environment (RLE). In the first study, performance of `Diamond' zoysiagrass …

Establishment And Management Practices Of Two New Warm-Season Turfgrasses In The Southern Transition Zone, John Stiglbauer

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Seashore paspalum (Paspalum vaginatum O. Swartz) is a turfgrass that has become increasingly popular in southern coastal regions of the US because of its ability to tolerate salt stress. Another reason that this turfgrass is increasing in popularity is its aesthetically appealing striping ability. Seashore paspalum could also be beneficial in areas where potable water cannot be used for irrigation. Information on this turfgrass is limited in literature, particularly on the topics of establishment, scalping, and growing this turfgrass on inland sites in the transition zone. A field experiment was conducted in Clemson, SC from May 2007 and 2008 to …

Refinement Of Innovative Watermelon Grafting Methods With Appropriate Choice Of Developmental Stage, Rootstock Type, And Root Treatment To Increase Grafting Success, Frederic Memmott

All Theses

ABSTRACT
Watermelon grafting methods used in Europe and Asia vary, but are based on efficiency, skill and needs. China mainly practices the whole insertion grafting method, whereas, Europe and Japan employ the one cotyledon (splice/slant–cut) grafting method. These methods are not suitable for grafting production in the U.S. due to the labor intensive and high labor cost necessary to successfully produce grafted transplants. This thesis introduced a modified grafting technique called the “Cotyledon Devoid Method” and in three experiments determined; 1) the rootstock leaf number stage (RLNS) at which the greatest grafting success is achieved; 2) the relationship between total …

Unrooted Stem Cutting Physiology; Water Use And Leaf Gas Exchange Of Severed Stem Cuttings, Peter Alem

All Theses

Stem cuttings are one of the most frequently used and successful methods of vegetative plant propagation. The understanding of unrooted cutting physiology, especially gas exchange and water flux, is crucial for successful propagation of healthy plants. Prior to root initiation, water uptake is limited and leafy stem cuttings are most vulnerable to wilting.
Experiments were carried out in the greenhouse with poinsettia cuttings to determine water uptake, photosynthesis, transpiration and stomatal conductance from the time of severing to rooting, including time spent in storage. Water uptake through the severed stem was investigated in the laboratory and growth chamber. Cutting gas …

Overseeded Bermudagrass Spring Trasition Response To Mowing Height, Nitrogen Rate, Sulfonylurea Herbicide, And Allelopathy, Raymond Mccauley

All Theses

Hybrid bermudagrass [Cynodon transvaalensis Burtt-Davey x C. dactylon (L.)
Pers.] is the preferred turf for golf courses and athletic fields across the southern United
States because of its dark green color, fine texture, good wear and drought tolerance, and
excellent recuperative rate. Despite its many attributes, bermudagrass goes dormant and
turns an unsightly brown color when soil temperatures fall below 10-13oC (50-55super>oF).
Perennial ryegrass (Lolium perenne L.) is often overseeded into bermudagrass in the fall
to sustain acceptable turf quality through the spring months. However, perennial ryegrass
aggressively competes with the bermudagrass for resources in the spring and potentially …

Root-Zone Characteristics And Bermudagrass Response To Saline Water Delivered By Subsurface Drip Irrigation, Kelsey Gorman

All Theses

Population growth and recurring drought conditions have placed high demands on freshwater resources in South Carolina. Thus, turfgrass irrigation management practices that reduce freshwater use while maintaining quality turfgrass need to be identified.
Previous research in the arid Southwest USA documents water conservation on bermudagrass by using saline water sources and subsurface drip irrigation (SDI) systems. A field-scale facility was constructed in Florence, SC, to evaluate `Tifway' bermudagrass
(Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt Davy) quality, growth, and rootzone characteristics when subjected to saline (3.15 dS m-1) or freshwater (0.07 dS m-1) irrigation, SDI lines spaced 41 or …

Physiological Response And Nutrient Recovery Of Cool-Season Turfgrasses Under Various Environmental Stresses, William Sarvis

All Theses

Potassium (K) is an essential plant nutrient commonly applied to increase creeping bentgrass tolerance to environmental stresses and maintain overall turfgrass stand health. Limited research defining the K requirement of creeping bentgrass under heat and drought stress exists. Furthermore, research investigating K, calcium (Ca), and magnesium (Mg) recovery under abiotic stress has been inconsistent. To build on previous research and investigate the differences between liquid and granular K fertilization, experiments were conducted to evaluate the performance of liquid and granular K carriers in conjunction with liquid calcium and magnesium on their ability to suppress summer bentgrass decline of creeping bentgrass …

Peach Tree Root Demography And Soil Microbial Characteristics In Peach Replant Soils, Shann Tanner

All Theses

Peach replant disorder (PRD) is a serious problem for peach growers throughout the United States. PRD refers to the pattern of reduced growth and yield observed in young peach trees planted on soil previously cropped with peaches. The conventional treatment for PRD, pre-plant soil fumigation with methyl bromide (a broad-spectrum biocide) adequately controls the disorder. This suggests that PRD results from harmful interaction(s) between the soil biotic community and peach roots. However, the specific causal agents of PRD are still unknown.
Methyl bromide is a known contributor to ozone depletion, and is only available to U.S. growers through Critical Use …

Hydraulic Resistance: A Determinant Of Short Term Stomatal Conductance Signaling In Disparate Xylem Anatomy Of Red Maple (Acer Rubrum L.) And Shumard Oak (Quercus Shumardii Buckl.), William Inman

All Theses

Recent work has shown that stomatal conductance (gs) and net photosynthesis (Anet) are responsive to the hydraulic conductance of the soil to leaf pathway (Xp). However, no study has compared xylem anatomical differences under controlled conditions to directly evaluate the whole plant hydraulic and chemical response to manipulations of Xp. Two tree species with differing xylem structures were used to study the effect of systematic manipulations in Xp that elevated xylem hydraulic resistance. Simultaneous measures of gs, Anet, bulk leaf abscisic acid concentration, leaf water potential, and whole plant transpiration were taken under controlled environment conditions. Shumard oak, a ring …

Thatch Control, Winter Painting, And Plant Growth Regulator Management On Golf Course Putting Greens, Steven Long

All Theses

No abstract provided.