Swegarden Cornellgrad 0058F
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DEPLOYING CONSUMER-DRIVEN STRATEGIES IN THE BREEDING OF LEAFY BRASSICA OLERACEA L. GENOTYPES A Dissertation Presented to the Faculty of the Graduate School of Cornell University In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Hannah Rae Swegarden August 2020 © 2020 Hannah Rae Swegarden ii DEPLOYING CONSUMER-DRIVEN STRATEGIES IN THE BREEDING OF LEAFY BRASSICA OLERACEA L. GENOTYPES Hannah Rae Swegarden, Ph.D. Cornell University 2020 Strategically targeting diversity within Brassica oleracea L. could expand existing market classes and products for changing food systems. Consumer acceptance and sensory perceptions of leafy Brassica cultivars have received minimal attention in developing strategic breeding approaches, and few sensory or consumer resources exist to inform the development of new cultivars. We deployed a series of consumer methods to generate a multi-faceted resource for breeding leafy Brassica vegetables with improved quality and potential to innovate produce markets. Qualitative Multivariate Analysis (QMA) identified underlying consumer values associated with kale consumption and highlighted consumer adherence to iconic kale and collard market classes. Quantitative approaches, including a trained descriptive panel and large consumer acceptance study, enabled the identification of 21 sensory attributes (primarily within the texture category) that varied among commercial cultivars and breeding materials. External preference mapping and agglomerative hierarchical clustering (AHC) identified four consumer clusters grouped closely with curly and Tuscan kale genotypes. In-situ sensory testing of collard genotypes in Upstate New York and Western Kenya underscored key considerations in conducting cross-cultural sensory studies. Flash Profiling (FP) with untrained consumer panels elucidated descriptive attributes iii in the consumer lexicon, while the number of attributes generated by regional panels did not closely correlate with familiarity or ability to differentiate products. Regional collard preferences were identified by a significant (p < 0.05) country-by-cultivar interaction for consumer acceptance. Eight morphologically distinct B. oleracea inbred lines were used as parents to develop a half-diallel mating design, which was subject to genotyping-by-sequencing (GBS), preliminary nutritional analyses, and an online consumer acceptance survey. After accounting for a strong correlation between liking and familiarity, a small heritable (h2 = 0.37) genetic component of consumer liking was identified. Genetic characterization of breeding materials confirmed their potential to add diversity to commercial market classes. Partiality to familiar kale and collard genotypes was a common theme throughout these studies. Continued interdisciplinary work is required to understand barriers to mitigate familiarity and introduce successful cultivars. This research serves as an important resource to leafy Brassica breeding and provides several models to integrate consumer research into breeding programs working with diverse or new crop types. iv BIOGRAPHICAL SKETCH Hannah Swegarden was raised in the Midwest and graduated in 2006 from John Marshall High School in Rochester, Minnesota. She pursued a B.S. in Biology at the University of Wisconsin – Eau Claire and subsequently entered a Floral Design program upon graduation. In 2012, she continued a lifelong quest to blend science and artistic endeavors by pursuing a M.S. in Horticulture at the University of Minnesota – Twin Cities with Dr. Thomas Michaels (Horticulture) and Dr. Craig Sheaffer (Agronomy). Her work at the University of Minnesota focused on the breeding and evaluation of heirloom dry beans for organic farming operations in the Midwest. Following graduation, Hannah continued to a Ph.D. program in the Horticulture Section at Cornell University. She joined the vegetable breeding laboratory of Dr. Phillip Griffiths (Cornell – AgriTech) in 2015. Her research in the Griffiths lab focused on breeding consumer quality traits in leafy Brassica vegetables and implementing methodology to integrate consumer feedback into the breeding program. Working in a diversified vegetable breeding program opened opportunities to explore fresh market vegetable development, production, and markets and more generally, allowed her to think about how she can creatively contribute to evolving food systems. In 2019, she married her husband, Roberto, and they eagerly welcome many more years of laughing and exploring together. v ACKNOWLEDGMENTS Thank you to my committee members, Dr. Phillip D. Griffiths, Dr. Steve Reiners, and Dr. Olga Padilla-Zakour for their continued patience and feedback throughout the implementation of this dissertation research. In providing me the freedom to think broadly, I’ve explored facets of interdisciplinary research I may not have otherwise. Thank you to our collaborators at the Cornell Sensory Center, Dr. Robin Dando and Alina Stelick, who provided me with the energy and foundational knowledge on which much of this dissertation was built. To the numerous individuals who sat with me and helped make sense of what I could not – Dr. Lynn Johnson, Dr. Zachary Stansell, Dr. Nicholas Santantonio, Dr. Charles Wasonga, and Dr. Carl Sams – thank you for your patience and creative interpretations. I am grateful to have worked with diverse partners throughout my degree, including GrowNYC/Greenmarkets, Cornell Cooperative Extension, Advantage Crops Ltd., field staff at the Homer C. Thompson Vegetable Research Farm, and grower collaborators in the upstate NY region. These experiences broadened my capacity as a horticulturist and created for impactful memories. Finally, I’d like to express my sincerest gratitude to my family and friends, namely Roberto, Mom, Dad, and Ben, for their continued support and encouragement. You all have been my sounding board through thick and thin, but your unconditional support has given me the confidence to persevere. vi TABLE OF CONTENTS BIOGRAPHICAL SKETCH.......................................................................................v ACKNOWLEDGMENTS...........................................................................................vi LIST OF FIGURES ............................................................................................... IX LIST OF TABLES ............................................................................................... XII LIST OF ABBREVIATIONS ............................................................................. XIV CHAPTER 1. LITERATURE REVIEW ................................................................. 1 DEFINING FRESH VEGETABLE QUALITY FOR CHANGING MARKETS AND CONSUMERS ... 1 PLANT BREEDING THROUGH THE LENS OF PRODUCT DEVELOPMENT ........................... 5 CONSUMER-DEFINED QUALITY IN THE CONTEXT OF A PLANT BREEDING PROGRAM ..... 7 BOTANY AND BREEDING OF BRASSICA OLERACEA L. VEGETABLES ............................ 13 Domestication and taxonomy ............................................................................ 13 Botany and mating systems............................................................................... 16 BREEDING FOR QUALITY TRAITS IN COLE CROPS ..................................................... 18 Pigment profiles ............................................................................................... 19 Flavor constituents............................................................................................ 24 Leaf morphology .............................................................................................. 27 TRANSLATING SENSORY SCIENCE TO A LEAFY BRASSICA BREEDING PROGRAM ........ 30 REFERENCES ......................................................................................................... 34 CHAPTER 2. BRIDGING SENSORY EVALUATION AND CONSUMER RESEARCH FOR STRATEGIC LEAFY BRASSICA (BRASSICA OLERACEA) IMPROVEMENT .................................................................................................. 47 ABSTRACT ............................................................................................................ 47 INTRODUCTION...................................................................................................... 48 MATERIALS AND METHODS ................................................................................... 53 Qualitative Multivariate Analysis (QMA) ......................................................... 56 Descriptive Analysis (DA) ................................................................................ 58 Consumer Central Location Test (CLT) ............................................................ 60 Statistical procedures and multivariate analysis................................................. 64 RESULTS AND DISCUSSION .................................................................................... 66 HUT journal feedback and value diagramming ................................................. 66 Trained panel assessments ................................................................................ 70 Hedonic CLT and consumer clustering ............................................................. 75 Perceptual mapping and external preference maps ............................................ 77 Integrative observations .................................................................................... 80 Application to future breeding efforts ............................................................... 82 CONCLUSION