Horticulture Commons^™

Investigating Effect Of Seed Source And Developing Germination Protocols To Improve Success In Restoration Of Arkansas Tallgrass Prairies, Rhiannon Spencerosa

Graduate Theses and Dissertations

American tallgrass prairie has faced losses estimated at 87-98% of original land area since European settlement. Native seeds are often used to supplement struggling or extinct plant populations in tallgrass prairie restoration and establishment sites. Two main considerations in restoration and establishment are from where to source seed and how to obtain high germination rates. In order to determine the effect of seed source, a common garden experiment was performed in Fayetteville, Arkansas in 2022 with five prairie species: Andropogon gerardii (big bluestem), Bouteloua curtipendula (sideoats grama), Panicum virgatum (switchgrass), Schizachyrium scoparium (little bluestem), and Sorghastrum nutans (Indiangrass). Seed was …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Managing Stress Tolerance On Warm-Season Putting Greens In The Transition Zone, Thomas Edward Walton

Graduate Theses and Dissertations

The use of warm-season putting greens in the transition zone has increased in recent years. Ultradwarf bermudagrass (Cynodon dactylon (L.) Pers x C. transvaalensis Burtt-Davy) is the most prevalent warm-season putting green selection in the transition zone, however, newly developed greens-type zoysiagrass (Zoysia spp.) cultivars represent another potential selection for golf courses. The two major limitations of warm-season grasses in the transition zone are a general lack of cold- and shade-tolerance. Protective covers are essential to protect ultradwarf bermudagrass putting greens in the winter months. Unfortunately, golf courses can still experience winterkill underneath protective covers. Two field trials were conducted …

Genetic Control Of Prickles And Plant Height In Blackberry, Carmen Johns

Graduate Theses and Dissertations

The fresh-market blackberry (Rubus L. subgenus Rubus Watson) industry has been expanding for the past two decades. Blackberry market growth can be attributed to many factors including expanded production regions, improved production systems, and release of superior cultivars. Blackberry breeding is a time- and labor-intensive process which would benefit from implementation of molecular markers for highly heritable, important traits. Next generation sequencing, a high-quality reference genome, and software capable of analyzing this complex genome were applied in a genome-wide association study (GWAS) to reveal maker-trait associations related to prickles and plant height variation in fresh-market blackberry. In 2020 and 2021, …

Genetic Control Of Sweetness, Acidity, And Seediness In Blackberry, Carly Elizabeth Godwin

Graduate Theses and Dissertations

The global blackberry (Rubus L. subgenus Rubus Watson) industry has experienced rapid growth during the past 15 years. Even so, many industry stakeholders report complaints from consumers and grocers stating blackberries are often too tart, too seedy, or not sweet enough for their liking. The development of molecular markers for high sweetness, low acidity, and reduced seediness would allow breeding programs to expeditiously make selection and crossing decisions in the early stages of the breeding pipeline. The objective of this study was to use a Genome-Wide Association Study (GWAS) to identify marker-trait associations, locate quantitative trait loci (QTL), and find …

Genetic Resistance To The Downy Mildew Pathogen And Breeding Towards Durable Disease Management In Spinach, Bazgha Zia

Graduate Theses and Dissertations

Spinach (Spinacia oleracea) is a self-pollinated, dioecious winter crop. Prevalent challenges to the production of spinach include disease pressure imposed by downy mildew, which is caused by Peronospora effusa (=P. farinosa f. sp. spinaciae [Pfs]). A total of 19 new races of P. effusa have emerged, imposing serious challenges to the disease management in spinach production. Accordingly, this study was designed to explore the genetic components for establishing the basis of durable disease resistance development against the downy mildew pathogen (P. effusa 13) in spinach, through the use of various genome engineering approaches.

Our results have led (Chapter 2) to …

Effect Of Harvest Time On The Incidence Of Red Drupelet Reversion And Development Of Tetraploid Linkage Maps In Blackberry, Mitchell E. Armour

Graduate Theses and Dissertations

The cultivated eastern U.S. blackberry (Rubus L. subgenus Rubus Watson) has gone through tremendous strides in both trait improvement and market outreach at the University of Arkansas System Division of Agriculture (UA System). What began as primarily a pick-your-own local fruit found mostly in the wild, has become a commercialized year-round product in most major U.S. grocery retailers. This could not have been achieved without decades of diligent breeding efforts. Although the genetic improvement of fresh-market blackberries has advanced, there are still issues that need to be addressed. One issue is the prevalence of red drupelet reversion (RDR), a physiological …

Evaluation Of Irrigation And Nutrient Management Strategies In Rice Using Alternative Irrigation Methods, Justin Lee Chlapecka

Graduate Theses and Dissertations

As water resources gain value across the Mid-South, alternative irrigation strategies of rice (Oryza sativa L.) have garnered increasing attention. In 2015, an estimated 1.7% of Arkansas rice hectarage used alternate wetting and drying (AWD) irrigation and 0.9% used furrow irrigation. As of 2020, 2.5% used AWD and 16.9% used furrow irrigation, the latter accounting for near 99,000 ha in Arkansas. Little information exists in the scientific literature in relation to management of rice grown in the Mid-South without a conventional flood. This fact coupled with the rapid adoption rate, especially for furrow-irrigated rice (FIR), during the last five years …

Phenotypic And Genotypic Studies In The Peach [Prunus Persica (L.) Batsch] And Muscadine Grape (Vitis Rotundifolia Michx.), Jennifer Anne Lewter

Graduate Theses and Dissertations

Peach: Peaches [Prunus persica (L.) Batsch] are routinely chilled to increase shelf-life. Exposure to temperatures of 5° C for two weeks can induce chilling injury (CI) symptoms, including flesh mealiness (or wooliness) and a lack of juiciness. Phenotypic data were collected on seven biparental F1 peach populations maintained at the University of Arkansas Fruit Research Station. A genome wide association study (GWAS) was performed using TASSEL 5 which identified four quantitative trait loci (QTLs) associated with expressible juice, four QTLs for mealiness, five QTLs for soluble solids, and three QTLs for fruit weight. Exploiting these genetic markers could help breeders …

Mapping Quantitative Trait Loci For Peach (Prunus Persica) Resistance To Xanthomonas Arboricola Pv. Pruni (Xap) And Determining The Diversity And Virulence Of A United States Xap Collection, Maxwell Vonkreuzhof

Graduate Theses and Dissertations

Bacterial spot, caused by the bacterium Xanthomonas arboricola pv. pruni (Xap), is a threat to the peach [Prunus persica (L.) Batsch], Japanese and European plum (P. salicina L. and P. domestica L.), and tart and sweet cherry (P. cerasus L. and P. avium L.) industries. Markers for fruit resistance to bacterial spot have been developed however, markers associated with foliar resistance have yet to be developed. A total of 130 progeny and 13 parents (n=143) were evaluated for foliar and fruit Xap resistance in 2013, 2014, and 2015, and 162 progeny and eight parents (n=170) in 2017 and 2018 as …

Taxonomy And Dna Barcoding In The Genus Manfreda (Salisb.) Asparagaceae, William David Ritchie

Graduate Theses and Dissertations

The genus Manfreda Salisb. of Asparagaceae is a genus of potential horticultural interest and is currently subject to breeding efforts at the University of Arkansas. A lack of taxonomic clarity however undermines the classification of potential inter - and intrageneric hybrids. The study aims to assess existing species delimitation within the genus Manfreda employing morphology while investigating the potential utility of Consortium for the Barcode of Life Plant (CBOL) DNA Barcodes for identification of specific taxa and an External Transcribed Spacer (ETS) - Internal Transcribed Spacer (ITS) DNA barcode for developed hybridized taxa.

Observation of 855 herbarium specimens facilitated phylogenetic …

Characterization And Molecular Analysis Of University Of Arkansas Peach, Prunus Persica (L.) Batsch, Flesh Types And Development Of A Post-Harvest Evaluation Protocol For Arkansas Peach And Nectarine Genotypes, Paul James Sandefur

Graduate Theses and Dissertations

This study determined the effect of pre-cold storage treatment on P. persica genotypes, developed a protocol for the evaluation of breeding selection and cultivar storage performance, and provided information on post-harvest performance of these individuals. Additionally, characterization of the peach and nectarine flesh types, validation of endopolygalacturonase (endoPG) DNA markers, and investigation of endoPG marker allele combinations associated with the slow-melting-flesh (SMF) trait were done.

Fruit from 30 individuals were harvested at minimum- and well-mature states. After conditioning for 24 h at 20 ◦C, all 2010 fruit were exposed to 2 min of 1 ◦C 100 ppm chlorinated hydro-cooling, a …