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Sweetpotato (Ipomoea batatas (L.) Lam.) (2n = 6x = 90) is among the most important vegetable crops. Breeding sweetpotato cultivars for increased yield and quality traits, as well as resistance to pests and diseases, has been the focus of breeding programs globally. Genomic tools to facilitate earlier breeding decisions, like marker-assisted and genomic selection, have lagged largely due to the complex genetics of sweetpotato. Resources now exist that have allowed breeders to implement these technologies, including the development of reference genomes and genomic tools specific to polyploid crops. Chapter 1 of this dissertation is a literature review describing these resources and tools in more detail, as well as the production and breeding of sweetpotato and some of the constraints to variety development.Chapter 2 describes strategies for high-throughput phenotyping resistance to Meloidogyne enterolobii, the guava root-knot nematode, a quarantined pest in the state of North Carolina. These approaches utilized machine learning to identify and count nematode eggs, information which can inform breeders as to the resistance level of a given sweetpotato genotype. Using convolutional neural networks and human-defined parameters, a hybrid machine learning model was able to detect eggs as well as human evaluators (M. enterolobii R2 = 0.985, M. incognita R2 = 0.992, M. javanica R2 = 0.983). Automated counting protocols have the potential to save hundreds of hours of labor while enhancing genetic gain for resistance for plant breeders.Chapter 3 details a QTL analysis focused on resistance to Fusarium oxysporum f.sp. batatas, commonly called Fusarium wilt disease. This was once the most important disease in US sweetpotato production, however, cultivar resistance has largely addressed this issue. In breeding for resistance to M. enterolobii, population-level resistance to Fusarium wilt disease may decline as some nematode-resistant lines lack Fusarium resistance. Over three trials, we bioassayed a 454-clone biparental mapping population, NCDM04-0001 x ‘Covington’, and found a single major locus on chromosome 10, herein named qIbFo-10.1, that explained 33.8% of variation for resistance to Fusarium wilt, suggesting resistance may be controlled by one or a few tightly-linked loci. This locus should be considered a priority target for marker-assisted breeding.Chapter 4 of this dissertation addresses quantitative traits, including yield, shape, and USDA grade by deploying genome-wide markers which can be used to predict the parental breeding value of a given individual for these traits. We utilized the DArTag genotyping platform and performed field trials on both a training and breeding population, each with 528 genotypes representing the NC State sweetpotato breeding program’s diversity. We compared BLUPs generated using mixed models and compared pedigree, genomic, and hybrid relationship matrices for trait predictions. Predictive abilities for the genomic BLUP model were highest in the breeding population for storage root count (r = 0.195) and length to diameter ratio (r = 0.317), and highest in the training population for total yield (r = 0.363) and USDA No. 1 storage root packout (r = 0.408). This provides evidence that genomic selection can increase the rate of genetic gain for quantitative traits in sweetpotato for the first time.Chapter 5 summarizes my experiences in the breeding program and includes details about several projects that were outside the scope of this dissertation. This chapter also identifies future research targets, including the use of drones for high-throughput phenotyping and future applications of genomic selection.This research strives to increase the rate of genetic gain for necessary traits for the sweetpotato breeding community. With the availability of genomic and high-throughput phenotyping tools, sweetpotato breeders can improve traits at the population-level, ultimately increasing the likelihood of selecting the next major sweetpotato variety.

Background Following a presentation to therapy colleagues on the benefits of horticultural therapy (HT) for clients with a range of health problems it was felt that clients attending our day hospice may benefit from a similar project. During conversations with day hospice attendees it was found that several clients had voiced their sadness that they were no longer well enough to tend to their own gardens and it was something they dearly missed. Following meetings with our colleagues, the therapy team agreed to pilot a six- month HT group. Two small successful funding applications allowed us to start in the Spring of 2016. Aim To provide two sessions per week, alternating days on a fortnightly basis. Each session lasting for approx one hour to include a variety of indoor and outdoor activities and run by an occupational therapist, assisted by our TI and faithful band of volunteers. Method Participation is voluntary. Numbers vary week on week dependent on the changing nature of their health status. Whilst there is a degree of planning we are guided by what clients and volunteers bring with them and their own ideas thereby ensuring they feel fully included in our overall aim to develop a patio are for all to enjoy. Ongoing evaluation The quick five question evaluation form centres around how the session has made our clients \"feel\" in terms of enjoyment, confidence, inner peace and energy. Results so far indicate significantly improved feelings and we have found clients eager to join the next group, often bringing in donations as well as their advice and expertise! Conclusion We are hopeful that following final evaluations, results will indicate a positive impact on those who have attended sessions and will lead to further funding to continue HT in our day hospice setting.

Electrical weeding is an emerging practice for late-season weed control that is being adopted in numerous cropping systems and agricultural industries, including Michigan vegetable production. However, little scientific research has been conducted directly evaluating the performance of electrical weeding and its effects on the agroecosystem. The objectives of the research program were to investigate electrical weeding in terms of 1) weed control, 2) crop injury, 3) economic viability, as well as its effects on 4) weed seed germinability and 5) rhizosphere microbial communities. Field trials at Hart, MI in 2021 and 2022 investigated these research objectives in conventional carrot and organic green bean production systems. Late-season weed control methods including one hand-weeding event (HW), one electrical weeder pass (1P), two electrical weeder passes performed consecutively [2P(ST)], one pass followed by one pass after a 14-day interval [2P(14d)], two passes followed by one pass after a 14-day interval (3P), and no late-season control (NLC) were evaluated in both carrot and green beans. Early-season weed control methods [low, medium, and intensive herbicide programs, weed-free, and no early-season control (NEC)] were also included in the carrot trials in order to produce different weed densities within which to assess the performance of the late-season weed control methods. In carrot, use of the intensive herbicide program typically led to lower densities of above-canopy redroot pigweed compared to NEC or the low herbicide program. There was no difference reported in redroot pigweed control with respect to early-season weed control methods after performing the various late-season weed control methods in 2021. However, in 2022, redroot pigweed control tended to be higher for treatments that caused initially lower weed densities (weed-free and intensive herbicide program). Increasing passes above 2P(ST) did not provide any higher control of redroot pigweed in carrot, while 3P did have higher weed control in green beans. Foliar injury did not exceed 10% in carrot and 20% for green beans. Electrical weeding did not cause any internal damage to carrot root tissue or have any effect on carrot root length. Hand weeding was correlated with a yield increase in 2022, whereas none of the electrical treatments led to any difference in yield in either year that was not related to natural variation in weed pressure. For green beans, neither electrical weeding nor hand weeding led to a yield difference in both years. Hand weeding had a significantly higher cost acre-1 than all electrical treatments in both years (19.6 and 28.4 times higher than 1P in carrot and green bean, respectively) due to the greater amount of time required. The range of time and cost acre-1 observed relates to the differences in weed pressure, where fields with higher weed competition requiring longer hand and electrical weeding times. Electrical weed control was found to significantly reduce redroot pigweed seed germination in 2021 (10 to 14%) but not in 2022. However, germination did not differ between early—or late season weed control methods in either year. Electrical weeding did not generally lead to differences in NH4+ or NO3– that would indicate changes in N mineralization in the rhizosphere. Microbial biomass C was higher after 1P than NLC in 2021. Apart from this, there were no differences in microbial biomass C or N reported with respect to early-season or late-season weed control methods in either year. Informed by the experimental results, growers can make more pragmatic decisions around investing in electrical weeding equipment based on its weed control performance, risk of crop injury, and economic feasibility compared with alternative late-season control practices. As well, electrical weeding has the potential to be an effective integrated weed management solution in vegetable production for control of the weed seedbank with little to no significant impacts on rhizosphere microbial communities.

Freestanding high tunnels are cost-effective, plastic film-covered growing structures that use very little to no modern environmental control technology. Natural ventilation is used to control temperature and humidity. This dissertation investigates design and management decisions that impact the high tunnel environment and ventilation, including vent design, high tunnel orientation, plant canopy height, shoulder-season management, and high tunnel row spacing. The main tool used for this investigation was computational fluid dynamics (CFD) simulations because they can accurately and quickly describe the airflow within a complex system, while allowing for an iterative design process. Field experiments were conducted at the Pennsylvania State University High Tunnel Research and Education Facility (Rock Springs, PA) in order to collect environmental data within and immediately outside of a reference high tunnel. This data was used to validate a CFD model made using commercially available software (ANSYS Fluent), which incorporated the physical processes of energy transfer (convection, conduction, and radiation), turbulence, plant canopy induced drag, plant evapotranspiration, and water vapor transport. The model had a root mean squared error of 1.17 °C (n = 144), showing good agreement between experimental and simulated results since this error is close to the measurement error of the temperature sensors used. Permutations to this base model were made to investigate the research questions posed. These included separate simulations of five roof vent designs, three tunnel orientations, three plant canopy heights, four distinct sets of weather conditions representing the colder periods of the year, and five row spacings for two differently sized tunnels (research size and commercial size). Finally, practical recommendations are presented related to how the findings of this dissertation can be implemented by growers.

Introduction: Previous studies have found that horticultural therapy (HT) is beneficial to different patient groups; however, its effect on frail seniors living in old-age homes has yet to be unveiled. Our study examines the effect of HT on the quality of life of frail residents, including their mood and sense of wellbeing, etc. Staff's perceptions of activities in residential settings have a substantial influence on their willingness and ability to engage residents in those activities, and therefore must be well appraised. The aim of this paper is to report a preliminary descriptive analysis of the staff's perspective of the effect of HT on the residents. Method: The entire HT project employed a mixed methods approach. This oral paper is a part of the qualitative limb of the approach. Content analysis was used to investigate the perspectives of the staff on the effect of HT on frail participants. After each cycle of 8-week HT sessions, a 15-item questionnaire was used to collect the perspectives of the staff who were involved in the HT study. Results: (1) participants enrolled in HT sessions were perceived as calmer and happier, and had more interactions with their family and other people; (2) frail residents were attracted to outdoor greenery, and this inspired the staff to consider it in their activity planning for the residents; and (3) staffing limitations and lack of suitable locations were perceived to be the challenges that hindered the sustainability of the activity. Conclusion: This study provides some preliminary findings on the perspectives of the staff on the effect of HT on frail seniors in residential care. The potential benefits of HT to the frail residents were observed, and the challenges to sustain such meaningful therapeutic interventions in care homes need to be addressed.