Viticulture and Oenology Commons^™

Evaluating Fungicide Programs For Grapevine Disease Management And Fungicide Sensitivity Monitoring, Abraham Ahumada

Master's Theses

Grapevine diseases, such as powdery mildew and Botrytis bunch rot, require repeated fungicide applications to maintain fruit quality and reduce yield losses. However, fungicide performance can vary among products, application programs, disease pressure, and pathogen sensitivity. This thesis evaluated fungicide programs for control of powdery mildew in ‘Chardonnay’ grapes and assessed fungicide sensitivity of Botrytis cinerea isolates collected from California vineyards.

Powdery mildew, caused by the fungal pathogen Erysiphe necator, is a major threat to the production of Vitis vinifera grapes worldwide. Because powdery mildew management relies heavily on fungicide applications, field evaluations are needed to compare the efficacy …

Chemical And Sensory Consequences Of Oxidative And Reductive Handling Of White Wines, Amelia Pargellis

Master's Theses

In the 2024 and 2025 vintage four experiments were performed each with a different varietal, namely Albariño, Grenache blanc, Loureiro, and Vermentino. These experiments investigated the effects of hyperoxygenation, reductive winemaking techniques, while monitoring the oxidation-reduction potential.

Albariño grapes were made following two juice protocols, control/reductive (Reductive Control) and oxidative (HyOx). Reductive Control received antioxidants (50 ppm SO₂, 160 mg/L ascorbic acid) and CO₂ blanketing, and HyOx underwent hyperoxygenation at approximately 700 mL/L/h of air for two hours through a stainless-steel sparging stone with 10-µm pores. Juice was cold-settled and racked. Reductive Control juice was split into …

Measurement And Control Of The Oxidation-Reduction Potential And Its Chemical And Sensory Consequences In Wines, William Jordan Wright

Master's Theses

The oxidation-reduction potential (ORP) is a measurement thought to reflect the overall ability of a solution to oxidize or reduce substances within that solution. In wine, there is no absolute agreement as to which substances control or dominate the ORP; however, oxygen, ethanol, iron-tartrate and copper-tartrate complexes, and glutathione are suspected to play key roles, while sulfur dioxide and phenolics may act as buffers. Anecdotally, some varieties of Vitis vinifera are prone to oxidation while others are prone to reduction, though the chemical basis of this remains unclear. The following works aim to further elucidate the influence of specific chemical …

Evaluating Nanobubble-Enriched Water Treatments For Cleaning Stainless Steel Winery Tanks At The Gallo Winery Research Station In Livingston, California, Edgar Godoy-Garcia

Master's Theses

ABSTRACT

Evaluating nanobubble-enriched water treatments for cleaning stainless steel winery tanks at the Gallo winery research station in Livingston, California.

Edgar A. Godoy-Garcia

Sanitation of stainless steel wine storage tanks is a critical component of quality control in commercial winemaking operations. Ineffective cleaning can lead to microbial contamination, product spoilage, and safety concerns. Traditionally, wineries rely on manual scrubbing, chemical cleaning agents, and extensive water rinsing cycles to maintain sanitary tank conditions. However, these methods are resource-intensive and may pose risks to both workers and the environment due to chemical exposure and wastewater generation. In response to growing industry interest …

A Mystery Of Microecology: Revealing The Ecological Relationship Between Allorhizobium Vitis And Missouri Native Grape Species, Hunter White

Graduate Theses/Dissertations

Crown gall disease can be very detrimental to grape and wine producers around the world by reducing vine vigor and yield. It is caused by the bacteria Allorhizobium vitis (A. Vitis) carrying a tumor inducing (Ti) plasmid. The A. vitis bacteria have been found in soil and cane tissues in vineyards around the world, and infect all cultivated grapes. However, there have been no reports of crown gall on native wild grapevines, and very little is known about the ecology of A. vitis in native ecosystems. I have sampled cambium tissues from three native wild grape species of …

Identification Of A Stable Qtl For Juice Color In A Vitis Interspecific Hybrid ‘Chambourcin’- Based Population, Qiuni Yang

Graduate Theses/Dissertations

Berry juice color is one of the key factors influencing grape and wine quality, consumer preference, and marketability. While most previous studies on berry color have focused on the skin, research on juice color remains limited. This study investigated the genetic basis of berry juice color in a hybrid population derived from the Vitis interspecific hybrid ‘Chambourcin’ and V. vinifera ‘Cabernet Sauvignon’. A new nine-category visual scoring system was developed to assess juice color based on OIV 225. To achieve comprehensive precision and quantitative analysis, CIELAB parameters (L*, a*, b*), Hue, and Chroma were extracted from image-based measurements. Using berries …

Revolutionizing Grapevine Breeding Programs: A Mobile Genome Editing System For Perennial Crops, Bridget Bolt

Theses and Dissertations--Plant and Soil Sciences

Grapevine (Vitis vinifera) faces unprecedented challenges from climate change, with up to 90% of current growing regions potentially becoming unsuitable for production within decades. Traditional breeding approaches require 25-30 years for variety development, creating a time constraint incompatible with the pace of environmental change. This research establishes the approach for a novel mobile RNA-based gene editing platform that addresses longstanding bottlenecks in grapevine improvement while preserving cultivar identity and reducing breeding timelines.

This research developed a three-component system for transgene-free gene editing in grapevine. First, a mobile CRISPR/Cas9 system was established using Agrobacterium rhizogenes transformation and the cut-and-dip …

Napa Valley Certified Organic Viticulture Napa Valley Vineyards Go Green: Transitioning To Organic Cultivation, Eric E. Tapia

Undergraduate Honors Theses

The shift to sustainable agriculture in Napa Valley necessitates certified organic vineyards among wine industry stakeholders to facilitate systemic change. Nonetheless, numerous impediments—such as fiscal constraints, inadequate access to information, and agricultural education—are intended to address these barriers for fostering an environmental stewardship program focused on innovation and sustainability. The methods employed to investigate the transition to organic vineyards include qualitative and quantitative approaches, such as interviews with vintners and data analysis of annual crop yields and the economic impact of certified organic vineyards in Napa Valley. The investigation reveals that vineyard proprietors face significant early challenges, including a steep …

Construction Of A Linkage Map Using Novel Dna Markers And Qtl Detection For Grapevine Powdery Mildew Resistance In 'Chambourcin’- Based Hybrids., Achyut Duwadi

Graduate Theses/Dissertations

In the midwestern United States, the Vitis interspecific hybrid ‘Chambourcin’ is a very popular winegrape. Powdery mildew, caused by the fungus Erysiphe necator, is one of the primary causes of grape yield loss across the globe. Presently, specific genetic determinants for resistance to E. necator remain undiscovered in ‘Chambourcin’. To identify these factors, a controlled leaf disc assay was conducted for two years using the Automated Phenotypic System (APS) with 273 F1 genotypes from a cross of ‘Chambourcin’ and V. vinifera ‘Cabernet Sauvignon’. Additionally, a pioneer linkage map using the same number of ‘Chambourcin’- derived hybrids was constructed with 355 …

Carbaryl-Induced Leaf Necrosis In Vitis Rupestris B-38, Courtney Nicole Duncan

Graduate Theses/Dissertations

Agricultural insecticides are formulated to target insects while minimizing harm to the intended crop. In rare instances, however, insecticides induce harmful physiological reactions in certain plant genomes, inflicting severe tissue damage. This project investigated the genetic basis of such a reaction observed in the grape genotype Vitis rupestris B38 following exposure to the insecticide carbaryl, which manifests as interveinal leaf necrosis. Through analysis of an F1 hybrid progeny of this grapevine, I mapped this phenotype to a QTL on chromosome 16. The carbaryl-sensitive trait was repeatedly mapped to the same locus using phenotype data from two different field locations and …

Cold Hardiness In Vitis Interspecific Hybrid 'Chambourcin'-Based Population, Tabinda Shahid

Graduate Theses/Dissertations

The susceptibility of grapevines to low-temperature injury presents a significant challenge, particularly in the United States. Traditional European grape cultivar, Vitis vinifera ‘Cabernet sauvignon’, faces bud damage at temperatures below freezing. On the other hand, Vitis interspecific hybrid ‘Chambourcin’, exhibits greater tolerance to sub-zero temperatures. The objective of this research was to conduct Differential Thermal Analysis (DTA) on 273 F₁ hybrid genotypes generated from a cross of ‘Chambourcin’ × ‘Cabernet Sauvignon’ to quantify bud cold hardiness by identifying the freezing exothermic reactions. Low temperature exotherm (LTE) profiles, over two dormant seasons (December to February 2022-2024), revealed 15 interspecific hybrid …

From Code To Crops: Harnessing Bioinformatics And Artificial Intelligence (Ai) In Agricultural Omics, Lakshay Anand

Theses and Dissertations--Plant and Soil Sciences

Global agricultural faces numerous challenges, such as climate change, resource limitations, novel pests and diseases, increasing costs, and the ever-increasing human population. To tackle these challenges, we need innovative strategies that combine new technologies and data analytics approaches to enhance agricultural output, promote sustainable methods, and optimize resource allocation. The key to this innovation lies in understanding the complex molecular web within plants that governs their growth, defense, and adaptability mechanisms. By mastering this molecular network, we can cultivate crops that are more resilient, sustainable, and suitable for different climatic terrains. Moreover, studying the symbiotic relationship between plants and microorganisms …

Effects Of Habitat Selection And Individual Quality On The Reproductive Success Of Barn Owls (Tyto Furcata), Jaime E. Carlino

Cal Poly Humboldt theses and projects

The hypothesis of adaptive breeding habitat selection proposes congruence between the evolved selection of habitats and fitness components such as reproductive success. However, mismatches between habitat selection and observed fitness outcomes are not unusual and can arise for multiple reasons. Variation in individual qualities of animals has also been found to affect reproduction and survival. I examined associations between barn owl nest box selection, reproductive output, and plumage characteristics previously shown to correspond to individual quality. I found that barn owls selected tall nest boxes made of wood, mounted high off the ground, and with increased proportions of grassland around …

The Temporal Evaluation Of Mouthfeel And Retronasal Sensations In Red Wines From The Central Coast Of California, Emily S. Stoffel

Master's Theses

Time-based sensory analysis techniques capture the dynamic retronasal and mouthfeel sensations in wines. It is important to understand how common winemaking practices and popular varietals impact the retronasal and mouthfeel profile as consumers tend to judge wine quality based on the taste, flavor, and mouthfeel of a wine. Three time-based sensory analysis methods were utilized with the objective to understand the effect of five commonly applied winemaking techniques (blending, varietal choice, fermentation temperature, cap management, and stem addition) on the dynamic retronasal and mouthfeel profile of six different varietals (Merlot, Malbec, Petite Sirah, Pinot noir, Grenache, and Tannat) grown on …

Morphological And Genetic Analysis Of The Root System In Two American Grapevines (Vitis Species), Parinaz Mohtasebi

Graduate Theses/Dissertations

The North American grapes species Vitis rupestris Scheele and Vitis riparia Michx have been the pillars of rootstock breeding for many decades. Though a large body of viticultural knowledge has been accumulated on their impact on grafted scions, the genetic basis of their root system architecture (RSA) has received limited scientific attention. In this study, I generated and analyzed adventitious root systems from dormant cuttings of 22 V. riparia and 19 V. rupestris accessions, as well as 162 interspecific F1 hybrid progeny from a cross between V. rupestris (♀) and V. riparia (♂). I photographed the roots and then extracted …

Distribution Patterns Of Allorhizobium Vitis In Missouri Vineyards And Non-Vineyard Soils, Jacquelyn M. Wray

Graduate Theses/Dissertations

Crown gall disease causes significant economic loss to the grape and wine industry. Preventive strategies are most effective for mitigating the loss of grapevines in vineyards, as there is no known cure for this disease. The bacterium Allorhizobium vitis carrying a tumor-inducing (Ti) plasmid is the causative agent. A. vitis bacteria live systemically in the grapevine before causing visible symptoms and can survive in residual plant tissues and soil for more than two years. Diagnostic methods have been developed to detect A. vitis bacteria in grapevines and soil. However, more reliable, specific, and high-throughput diagnostics are still needed for screening …

Investigating Quality Attributes And Wine Production Methods Of Arkansas-Grown Grapes, Amanda Fleming

Graduate Theses and Dissertations

Grapevines (Vitis species) are grown worldwide to produce table grapes, juice grapes, dried grapes, and wine with the United States as one of the world’s largest wine and grape producers. Though not a large contributor to the U.S. grape and wine industry, Arkansas’ industry plays an important role in the state’s agritourism and economy. Most grapes grown in Arkansas’ warm climate include native species, such as muscadines (V. rotundifolia) and hybrids (crosses of Vitis species). Two important hybrid red wine grapes grown in Arkansas are Chambourcin, grown commercially for its positive viticulture and enological quality, and Enchantment, a newer cultivar …

Vermicompost Versus Traditional Compost Amendments Leads To Different Soil Health Outcomes In A Mediterranean Vineyard, Elizabeth L. Luck

Master of Science in Environmental Sciences and Management Projects

Compost application has become a common practice in vineyard management to increase soil and crop health, however, the environmental externalities such as greenhouse gas emissions (GHG) from cropping systems that utilize organic fertilizers, such as compost, is uncertain. Vermicompost, which is compost created through the digestion of organic matter by earthworms, and its related ‘extract’ are commonly thought to provide more benefits for soil and crop health compared to standard compost. However, organic fertilizers such as vermicompost, vermicompost extract, and compost have not been compared in their effects on soil health in Mediterranean vineyards. In this two-year study, I assessed …

Determination Of Fungicide Resistance In Botrytis Cinerea On Wine Grapes In California's Central Coast Region, Evelyn Alvarez-Mendoza

Master's Theses

Botrytis bunch rot, caused by Botrytis cinerea, is a fungal disease that primarily affects the fruit of wine grapes. Infection of fruit consequently results in reduced yields and wine quality. These factors lead to significant economic losses for growers which prompts the implementation of management practices to control the disease. One objective of this study was to evaluate the level of resistance that populations of B. cinerea in the Central Coast region showed to various chemicals. A fungicide assay was conducted to determine resistant phenotypes to six fungicide active ingredients (pyrimethanil, iprodione, fenhexamid, fludioxonil, trifloxystrobin, boscalid). Thirty-five (2020) and …

Cofermentation, Post-Alcoholic, And Post-Malolactic Fermentation Blending Of Malbec, Merlot And Petite Sirah Wines, Armando Arturo Vega-Osorno

Master's Theses

A two-year study was conducted to assess the effects of cofermentation on red wine varietals. During the winemaking process, wines can be made from two or more varieties by picking, crushing and fermenting them together, a practice known as cofermentation. They can also be blended either after the completion of alcoholic fermentation or after malolactic fermentation. In the first year of the study, two grape varieties, Merlot (Mer), and Malbec (Mal) were cofermented. On the second year, a third varietal, Petite Sirah (PS) was also studied. Cofermented wines containing every possible binomial combination of the varietals was made and one …

Muscadine Grapes: Identifying Unique Attributes And Postharvest Practices, John Cody Rawls

Graduate Theses and Dissertations

Arkansas has a long history of grape and wine production, and muscadine grapes (Vitis rotundifolia Michx.), a native disease-resistant grape, are an important part of that industry. Muscadine grapes can be sold as a fresh-market grape or made into juice, wine, and other products. Additionally, the University of Arkansas System Division of Agriculture (UA System) breeding program has a focus on creating new muscadine cultivars with commercial potential. The objectives of this research were to evaluate muscadine grape genotypes (cultivars and breeding selections) for fresh market consumption and wine production in 2020 and 2021. 33 seeded and seedless genotypes of …

Evaluating Flavor And Aroma Attributes Of Arkansas-Grown Horticultural Crops, Jordan Chenier

Graduate Theses and Dissertations

Arkansas has a climate and geography that allows for the production of unique horticultural crops, including hops (Humulus lupulus L.), blackberries (Rubus subgenus Rubus), and muscadine grapes (Vitis rotundifolia). These crops not only have potential for growers in Arkansas but have unique flavor and aroma attributes that impact marketability. Volatile compounds present in many different agricultural plants are the primary source of biologically-derived aromas and flavors. Therefore, the volatile and other quality attributes of hops, blackberries, and muscadine grapes were evaluated at the University of Arkansas (UA System) Division of Agriculture. The quality, volatile, and sensory attributes of four hops …

Effect Of Vine Age And Selected Winemaking Techniques On The Sensory Profile Of Central Coast Red Wines, Isabelle Lomonaco

Master's Theses

Descriptive sensory analysis is essential to understanding how differing varietals, viticultural techniques, enological techniques, vintage, regions, etc. impact the sensory characteristics found in wines. These studies analyzed the sensory impacts of vine age, whole cluster and stem addition influences, the frequency of cap management regimes, and selected fermentation variables, on 2019 Zinfandel, 2020 Syrah, 2020 Tannat, 2020 Cabernet Sauvignon, and 2021 Graciano wines respectively, from the Central Coast of California, USA. The investigation of Old vine Zinfandel indicated that these wines were defined as complex due to the wide variety of descriptors used to characterize them, having high color saturation …

An Investigation Of Factors Affecting The Rooting Ability Of Hardwood Muscadine Cuttings And Genetic Diversity Of Wild And Cultivated Muscadine Grapes (Vitis Rotundifolia Michx.), Kenneth Buck

Graduate Theses and Dissertations

The muscadine (Vitis rotundifolia syn. Muscadinia rotundifolia) is a grape species native to the southeastern United States. Muscadines are one of three grape species in subgenus Muscadinia with a chromosome number of 2n=40 (V. rotundifolia, V. munsoniana, and V. popenoei), making them genetically distinct from the European wine and table grape (Vitis vinifera) and other species in subgenus Euvitis. Rooting hardwood cuttings from muscadine vines has traditionally been considered an exceptionally difficult task. Many previous studies observed almost no root formation, leading to a general consensus that muscadines should either be propagated by softwood cuttings or vegetative layering. However, the …

Analysis Of Root System Architecture And Qtl Identification In Grapevines, Sujan Thapa

Graduate Theses/Dissertations

The root system of the plant plays a vital role in water and nutrient uptake. Native North American grapevines adapted to a broad range of climatic and soil conditions, which led to the evolution of diverse root system architecture (RSA) within the Vitis genus. Despite the importance of RSA in viticulture, little is known about the genetic basis of the RSA in grapevine. I used novel root phenotyping tool, RhizoVision Analyzer to characterize the root system of 208 genotypes of an F₁ grapevine progeny obtained from a cross between Vitis rupestris Scheele B38 and Vitis riparia Michx. HP-1. Dormant …

Marker-Assisted Selection To Determine The Introgression Of Rpv-3 Mediated Downy Mildew Resistance In 'Chambourcin' X 'Caberenet Sauvignon' Grapevine Population, Kavya Sri Tummala

Graduate Theses/Dissertations

Downy mildew caused by the fungus, Plasmopara viticola in the grapes is one of the major diseases affecting crop yield throughout the world. Breeding grapes via conventional methods for the downy mildew resistance will take approximately 25-30 years to fully evaluate and release new cultivars. Because of the long breeding cycle in woody plant species like grape, developing DNA markers linked to genes or quantitative trait loci (QTLs) for horticultural traits can greatly accelerate the breeding process and allow a much more accurate selection of progeny. This study aims to determine the presence of resistance in the 267 F1 genotypes …

Identification Of Qtls For Berry Acids And Sugar In A Vitis Aestivalis-Derived 'Norton'-Based Population, Karlene Louise Negus

Graduate Theses/Dissertations

Acidity and sugar content are among the grape berry quality traits that influence wine quality. Despite advantageous environmental tolerances of Vitis aestivalis-derived ‘Norton’, its acid and sugar concentrations often deviate from expectations set for V. vinifera. Identification of the genetic determinants of malic acid, tartaric acid, pH, and total soluble solids (TSS) can assist in the improvement of new hybrid cultivars. For this purpose, a ‘Norton’ and V. vinifera ‘Cabernet Sauvignon’ hybrid mapping population containing 223 individuals was used to construct a linkage map containing 384 simple sequence repeat (SSR) and 2084 genotyping-by-sequencing (GBS)-derived single nucleotide polymorphism (SNP) …

Climate Adaptation And Water Conservation Decision-Making In Paso Robles, California Vineyards, Christopher R. Klier

Master's Theses

This paper examines vineyard perceptions and adoption of climate change adaptation and water conservation measures in the Paso Robles American Viticultural Area (AVA). A survey was distributed to all 220 vineyards and vineyard management companies that operate in the AVA, with a 53.64% response rate. The objective of the survey was to determine vineyard manager and owner attitudes towards climate change and adaptation, as well as their perceptions of how these threats would impact their operation. A second objective was to document the current level of water conservation and climate adaptation while identifying the barriers and opportunities for further adoption …

The Effects Of Vine Age On Vine Performance, Fruit, And Wine Composition Of Zinfandel In The Templeton Gap Ava, California, Vegas L. Riffle

Master's Theses

A two-year study was conducted at a commercial vineyard in California’s Templeton Gap AVA to evaluate the effect of vine age on viticultural, enological, and sensory attributes of Vitis vinifera L. cv. Zinfandel grapes and wines. The experimental block was dry farmed, conventionally managed, with own-rooted Zinfandel vines that, when determined unproductive, were replaced with new vines of genetically identical scion plant material grafted onto St. George (Vitis rupestris Scheele) rootstock. Treatments included Young vines (5 to 12 years old), Control (representative proportion of young to old vines in the block), and Old vines (40 to 60 years old). …

Analyzing Purchase Behavior For Domestic And Imported Dry Wines In The U.S. Market Using Panel Data, Nadica Koskarovska

Graduate Theses and Dissertations

The objective of this study is to explore wine purchase behavior in the United States market, including different off-premise channels using AC Nielsen panel data and wine prices and rankings from the Wine Enthusiast database of wine reviews. The purpose of this thesis is to identify factors that impact customer loyalty to retail wine brands. In so doing my goal is to provide information that can be used to improve marketing efforts of small wineries that are seeking to grow into mainstream retail formats. The results suggest that efforts to build brand equity will be more successful if the brand …