Horticulture Commons^™

Evaluation Of Nitrous Oxide Emissions From Furrow-Irrigated Rice On A Silt-Loam Soil In Arkansas, Jordan M. Slayden

Graduate Theses and Dissertations

As the number one rice (Oryza sativa)-producing state in the United States, Arkansas also ranks fourth as the largest user of groundwater. Recently, due to the development of drought- resistant hybrid cultivars, the furrow-irrigated rice production system has become an increasingly popular alternative to traditional flood-irrigated production with respect to conserving groundwater and maintaining yield. However, other environmental parameters, like greenhouse gas emissions, specifically nitrous oxide (N2O), have yet to be evaluated under furrow-irrigated rice. The objectives of this study were to i) evaluate the effects of site position (i.e., up-, mid-, and down-slope) and tillage treatment [i.e., conventional tillage …

Winter Cover Crop Mixes: Effects On Strip-Tilled Plasticulture And No-Till Watermelon Production In Arkansas, Alden Neil Hotz

Graduate Theses and Dissertations

Watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai, producers in Arkansas grow watermelons in either plasticulture or bare-ground systems. Both systems can benefit from the use of winter cover crops for weed control and to supply nitrogen (N) to the watermelon crop. Currently, the use of cover crops in watermelon production in AR is mostly limited to either cereal rye (Secale cereale L.) or winter wheat (Triticum aestivum L). The objective of this research is to evaluate the potential benefits of growing a mix of a legume and grass cover crops before watermelon production in both a strip-till plasticulture and a …

Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer

Graduate Theses and Dissertations

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such …

Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston

Graduate Theses and Dissertations

Nutrient management in recirculating hydroponic systems requires the periodic replenishment of water and nutrients to the nutrient solution reservoir. Common nutrient management strategies, such as replenishing the reservoir with fresh solution and maintaining a constant solution electrical conductivity (EC), can lead to ion accumulation and nutrient imbalances since nutrients are taken up by roots and depleted from solution at different rates. To avoid nutritional disorders, commercial growers typically dump and replace the hydroponic solution periodically, which is wasteful and has an economic cost. A potential alternative is to specially formulate the nutrient replenishment solution to balance the supply of nutrients …

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 …

Impact Of Planting Arrangement And Drill Row Spacing For Direct-Seeded, Delayed Flood Rice, Mary Jane Lytle

Graduate Theses and Dissertations

Direct-seeding is the most frequently utilized planting practice in Arkansas and Mid-South rice (Oryza sativa L.) production. Enhanced plant density and more rapid rice canopy formation may result from the implementation of innovative plant arrangements and spacings. Studies were initiated in 2019 and continued into 2020 to examine different cultural management practice experiments, including evaluating the impacts of planting arrangement, row spacing, and seeding rates on rice stand density, canopy coverage, grain yield, and milling yield. These small-plot trials were conducted at two locations, a silt loam site and a clay site, representative of soils produced to rice in eastern …

Nocturnal Pollination In Fruit Agriculture, Stephen Robertson

Graduate Theses and Dissertations

Insect pollination in agriculture provides as much as 35% of the global food supply and contributes hundreds of billions of dollars to the global economy each year. In the past 30 years, reports of declining populations of managed and wild bees, notably the western honey bee (Apis mellifera) and a wide array of bumble bees (Bombus spp.), have raised concerns about the stability and outlook of agriculture. At the same time, agricultural dependence on insect pollinators is increasing as greater percentages of land being converted to pollinator-dependent crops, such as soy and oil palm, than pollinator-independent crops, such as grains …

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 …

Resistance Screening And Association Mapping For Resistance To The Downy Mildew Pathogen Of Spinach, Dotun Olaoye

Graduate Theses and Dissertations

Spinach is an important cool leafy vegetable cultivated around the world, with large scale production in California and Arizona in the U.S. Spinach is a highly nutritious vegetable beneficial in the human diet. Spinach is affected by a number of biotic stressors. Downy mildew, caused by the oomycete pathogen Peronospora effusa, is a major threat to spinach as it affects the leaf quality and impacts the economic value of spinach. Several efforts have led to the development of resistant genotypes/cultivars to this pathogen. However, few studies have examined the genetics of resistance to the downy mildew pathogen in detail. This …

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 …

Comparison Of A T-Trellis And A Rotating Cross-Arm Trellis For Arkansas Blackberry Production, Erika Henderson

Graduate Theses and Dissertations

As blackberry production in the southeastern United States expands, the need for updated cultural practices, like alternative trellis systems that enhance blackberry fruit yield, fruit quality, and economic viability for fresh-market growers are needed. There are challenges to producing high-quality blackberry fruit with high yields in the Southeast due to intense heat, high rainfall, humidity, and heavy pest pressure. Southeastern growers are interested in the rotating cross-arm (RCA) trellis due to its potential to increase yield and fruit quality, however there is minimal research of its use in blackberry production in the Southeast. In 2019 and 2020, a trial was …

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 …

Performance Evaluation Of Four Arkansas Table Grape Cultivars Grown On Three Trellis Systems Under High Tunnels At Two Locations In Arkansas., Jose Hernandez

Graduate Theses and Dissertations

Grapevines (Vitis vinifera L.) are one of the most important horticultural crops world-wide. In the southern U.S. region, hot and humid climate accompanied by high pest pressure requires high levels of labor and pesticide inputs, making open field table grape production unsustainable. Previous research at University of Arkansas has demonstrated that table grape production under high tunnels (HTs) is a viable option to overcome biotic and abiotic challenges in the region. This project evaluated two HTs established in Arkansas. In the spring of 2014, at Fayetteville, three table grape cultivars (Faith, Gratitude, and Jupiter) were established in an 8 x …

Genetic Architecture Of Salt And Drought Tolerance In Cowpea, Waltram Second Ravelombola

Graduate Theses and Dissertations

Cowpea [Vigna unguiculata (L.) Walp.] is a diploid and nutrient-dense legume species. It provides affordable source of protein to human. Cowpea cultivation is prevalent in Africa, Asia, the western and southern U.S., and Central and South America. However, earlier reports have shown that drought and salt stress can be devastating to cowpea production. The objectives of this study were to screen for salt and drought tolerance in cowpea and to identify molecular markers associated with these traits. Simple methodologies to screen for drought (Chapter 2) and salt tolerance were developed (Chapter 3). Results suggested that: 1) a total of 14, …

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 …

Determining Cluster Thinning And Storage Effects On Fruit Quality And Marketability Attributes Of Arkansas Table Grapes Grown Under High Tunnel Systems., Virginia Beasley

Graduate Theses and Dissertations

Table Grapes (Vitus vinifera) are highly valued horticulture crops world-wide. Often, table grape production in the southern United States is restricted due to climate and pest issues. Viticulture production could be expanded to this region by the use of controlled environment growing systems, such as high tunnels (HT). The objective of this project was to evaluate the effectiveness of HT systems for grape cultivation and compare the effects of different cluster thinning treatments on vines. In this two-year study, the cultivars Faith, Gratitude, Hope, and Jupiter were grown in HT systems and assessed for postharvest qualities at harvest and during …

Phylogenetic Diversity Of Arkansas Vineyard And Wine Microbiota, Natacha Cureau

Graduate Theses and Dissertations

Microorganisms inhabiting the soil, leaves, and grapes in vineyards influence the terroir, a set of environmental factors that impact wine characteristics. Previously, the main method to identify microorganisms was to culture on different media, but a large portion (> 99%) could not be cultured and were consequently unidentified. However, the emergence of new molecular tools has enabled further study and identification of microorganisms such as indigenous vineyard microbiota. The objective of this research was to investigate the phylogenetic diversity of Arkansas vineyard and wine microbiota using high-throughput sequencing. In terms of the Arkansas vineyards, the fungal and bacterial diversity of …

Midseason Nitrogen Sufficiency Guidelines For Corn Production In Arkansas Based On Tissue Analysis And Remote Sensing, Caio Luiz Dos Santos

Graduate Theses and Dissertations

There are a lack of tools to assess midseason nitrogen (N) status in corn (Zea mays L.) production systems and identify the need for additional N fertilization. This study was conducted to determine the ability of leaf N concentration (LN) and the Dark Green Color Index (DGCI) at the 10th collared leaf stage (V10), the 12th collared leaf stage (V12), and tasseling (VT) to predict if midseason N is required to maximize corn grain yield. From 2017 to 2019, eight field studies with 11 N treatments ranging from 0 to 258 kg N ha-1 were conducted on silt loam soils …

Techniques To Enhance The Attributes Of Wines Produced From Grapes Grown In Arkansas, Sarah Mayfield

Graduate Theses and Dissertations

Grapevines (Vitis spp.) are one of the most widely-planted horticultural crops, and the United States plays a major role in grape and wine production. Arkansas has a long history of grape and wine production with grapes grown in Arkansas including mostly native species, such as muscadines, and hybrids (crosses of Vitis spp.), such as Chambourcin. In addition, the University of Arkansas System Division of Agriculture (UA System) grape breeding program has cultivars and selections that have shown potential for wine production. The objectives of this research were to: evaluate effects of specific inactivated yeast application to Chambourcin grapevines on attributes …

Hydroponic And Soilless Culture Systems And Transplant Practices Influence Production Of Basil (Omicum Basilicum L.), Samuel Warren Edward Doty

Graduate Theses and Dissertations

Two controlled-environment greenhouse experiments evaluated (1) plant growth and morphology of basil (Omicum basilicum L.) grown in three different hydroponic and soilless substrate systems and (2) seedling tray cell-count and transplant date into hydroponic culture effects on basil growth and yield at harvest. For the first experiment, four basil cultivars (‘Genovese’, ‘Mrs. Burns Lemon’, ‘Sweet Thai’, and ‘Cinnamon’) were grown in deep flow technique (DFT) hydroponics, nutrient film technique (NFT) hydroponics, and a novel shallow aggregate ebb-and-flood (SAEF) soilless substrate system and were harvested after 21 d. Plant yield and morphological characteristics measured at harvest included shoot fresh mass, shoot …

An Evaluation Of Biopesticide Combinations On Yield Performance And Disease/Arthropod Control Of Strawberries Grown In High Tunnel Plasticulture Production Systems In Arkansas., Karlee B. Pruitt

Graduate Theses and Dissertations

This two-year study investigated combinations of biopesticides to determine impacts on strawberry fruit marketable fruit yields, and effectiveness in controlling strawberry pests in a high tunnel production system at the University of Arkansas, Division of Agriculture Research and Extension Center in Fayetteville, Arkansas. Two strawberry cultivars Fragaria × ananassa (Duch.), Camino Real and Sweet Sensation were grown in a high tunnel from early-October to mid-May for two consecutive growing seasons, (2017-18 and 2018-19) with six treatment combinations of biopesticides including an untreated (water) control, nutrient spray and selected biological based fungicides and insecticides, arranged into a split-plot randomized block design. …

Florpyrauxifen-Benzyl Use In Arkansas Rice (Oryza Sativa L.), Hannah Elizabeth Wright

Graduate Theses and Dissertations

Florpyrauxifen-benzyl is a synthetic auxin herbicide which was commercially released in 2018 to combat troublesome grass, broadleaf, and sedge weed species in rice. Many factors may influence cultivar response to a new herbicide; hence, it is important to understand factors contributing to crop sensitivity to an herbicide in order to make appropriate recommendations. Prior to the onset of this study, research had been conducted on florpyrauxifen-benzyl in a flooded environment; however, none had been executed in a non-flooded environment. Experiments were conducted to evaluate the response of a long-grain variety ‘CL111’, a medium-grain variety ‘CL272’, and a long-grain hybrid ‘CLXL745’ …

Cover Crops As An Integrated Approach For Pest Suppression And Pollinator Promotion In Arkansas Watermelon Production Systems, Paige Laurel Hickman

Graduate Theses and Dissertations

Arkansas watermelon growers face a variety of insect pest and disease problems that have the potential to threaten yield. Integrated pest management tactics can provide control over these threats and are intended to cut down on pesticide use and its associated negative impacts like pesticide resistance, non-target effects, and runoff. Cover crops provide an array of benefits and can be useful in integrated pest management. Evidence has shown that certain cover crops can increase beneficial insects and suppress disease in the following cash crop. They can also provide important resources to pollinators. In order to build a better understanding of …

Methods To Evaluate Ruminant Animal Production Responses, Jose Manuel Diaz Gomez

Graduate Theses and Dissertations

In experiment 1, 80 steers (197.0 kg initial body weight; BW for fall, 116.9 kg for spring), were stocked at 2.45 and 4.1 calves/ha in fall and spring, respectively in 16 tall fescue pastures [fall ergovaline (EV) = 1,475 ppb and spring EV = 1,173 ppb] under 2 treatments, mineral (MIN) (n = 8) and cumulative management (CM) (n = 8). Forage allowance did not differ (P = 0.76) between CM and MIN during fall but differed during spring (P ≤ 0.05, 2.55 vs. 3.22 kg DM/kg BW, for MIN and CM, respectively). For fall, average daily gain (ADG) resulted …

Determining Water Requirements In Turfgrass Systems, Tyler Quinn Carr

Graduate Theses and Dissertations

Turfgrass lawns are commonly utilized for home and commercial applications because of the aesthetic, environmental, and recreational benefits grasses provide, but many people perceive turfgrass as solely an aesthetic benefit that requires significant water inputs. It is important to identify and use turfgrass cultivars that have known drought tolerance, and also fine-tune and throughout development. A series of field experiments were conducted to determine the water requirements of turfgrass lawn systems with the following objectives: 1) investigate differences in chronic drought resistance and irrigation recommendations among cultivars of Kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) 2) …

Genetic Resistance To The Downy Mildew Pathogen And Mapping The Rpf Resistance Loci In Spinach, Gehendra Bhattarai

Graduate Theses and Dissertations

Spinach (Spinacia oleracea) is an important cool-season leafy vegetable crop in the United States (US). Downy mildew, caused by the obligate oomycete Peronospora effusa, is the most economically important disease of spinach. A total of 17 races of P. effusa have been reported on spinach, and many of these races (>10) have emerged in the last three decades. The new races of the pathogen are continually overcoming the genetic resistances used in the newly released cultivars.

A detached leaf inoculation assay was evaluated, standardized, and validated as a new method to differentiate resistant and susceptible spinach genotypes. Disease response …

The Evaluation Of Low-Use-Rate Zinc Fertilization Strategies On Seedling Canopy Coverage, Zn Concentration, Biomass, And Grain Yield, Maxwell David Coffin

Graduate Theses and Dissertations

Zinc (Zn) is the most common micronutrient deficiency in flooded rice (Oryza sativa L.). Some new Zn fertilization methods have been advertised, but have limited research supporting their efficacy. This study mainly compared the effect of Zn-seed treatment rate in combination with other low-use-rate Zn-fertilization methods to the standard of 11 kg Zn ha-1 as ZnSO4 on rice early-season canopy cover, tissue-Zn concentration, and grain yield. A secondary objective evaluated an alternative method (to seed treatment with ZnO) of enhancing seed-Zn concentration using post-heading foliar-Zn application on seedling tissue-Zn concentration and grain yield. For the main objective, rice seed was …

Assessment Of Control Of Ppo-Resistant Palmer Amaranth And Salvage Options In Herbicide-Resistant Cotton, Wyatt D. Coffman

Graduate Theses and Dissertations

Palmer amaranth has been the most limiting weed in cotton production in the state of Arkansas for many years. Recently, resistance of Palmer amaranth to the protoporphyrinogen oxidase (PPO)-inhibiting site of action has been discovered at various locations across the cotton-producing region of the state. Cotton varieties have been developed with resistance to synthetic auxin (WSSA Group 4) herbicides. However, research to date has shown PPO-resistant Palmer amaranth to be more difficult to control with herbicides that target alternative sites of action. Herbicide efficacy is also known to vary with weed size, varying spray parameters, and environmental conditions. Preliminary research …

Water Conservation Practices For Irrigation Of Turfgrass Lawns, Daniel Sandor

Graduate Theses and Dissertations

Turfgrass lawns are widely used in residential and commercial landscapes, providing many environmental, aesthetic, and recreational benefits. However, concerns and scrutiny arise with perceived maintenance requirements, particularly with regards to irrigation. It is important to manage irrigation in order to maximize water conservation without significantly reducing lawn quality. A series of field and greenhouse studies were conducted to investigate how water usage might be reduced in irrigation practices with the following proposed objectives: 1) evaluate the use of rain and soil moisture sensors in a humid transition zone environment; 2) evaluate the effects of chronic drought stress between drought-resistant and …