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Browsing Theses and Dissertations by Author "Anthony, Brendon, author"

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    Influence of preharvest factors on peach fruit quality and metabolism
    (Colorado State University. Libraries, 2021) Anthony, Brendon, author; Minas, Ioannis, advisor; Musacchi, Stefano, committee member; Prenni, Jessica, committee member; Bunning, Marisa, committee member
    Worldwide peach consumption has been in steady decline throughout the past few decades due to poor fruit quality and consumer experiences. Fruit quality is developed in the orchard by optimizing preharvest factors and orchard practices. Several studies have been conducted to understand how these factors influence peach internal quality, but fail to control for confounding variables. One particular confounding variable that is influenced by preharvest factors and directly impacts fruit quality is maturation. Pomological experiments investigating the impact of preharvest factors on internal fruit quality must control for maturity. Historically, maturity control through destructive and subjective methods was not feasible nor efficient. The development of new technologies, such as visual radiation and near-infrared spectroscopy allowed the development of novel maturity indices (index of absorbance difference) that can be used for maturity control and quality assessment simultaneously in a single scan. The following literature review and experiments investigate three critical preharvest factors: training systems, canopy position and crop load (i.e., carbon supply), for their true impact on peach fruit quality development and metabolism, while controlling for maturity. The training system review demonstrates the progression of orchard design from three-dimensional, low-planting densities to planar, high-density plantings through the application of size-controlling rootstocks and vigor diffusion architecture. The canopy position trial revealed that the fruit's light environment is more influential in quality development and metabolic shifts than genotype or position alone. Canopies with uniform light distribution generate fruit of uniform quality and metabolite profiles across distinct positions. Fruit under sufficient carbon supply (i.e., thinned fruit) will exhibit superior quality and phenotype when compared to carbon-starved fruits at harvest, even when assessed at equal maturity. Primary metabolite profile differences between distinct carbon supply conditions are minimal at harvest due to experimental maturity control and metabolic processes being heavily regulated by development and maturation. While differences in secondary metabolite profiles are more distinct at harvest between carbon supply treatments. Although, both the primary and secondary metabolism demonstrate vast profile differences between carbon supply treatments early, and may prime the quality phenotype at harvest. Flavonoids are consistently elevated in carbon sufficient fruit throughout development. Phenylpropanoids, such as catechin, along with benzenoids, sucrose and sorbitol demonstrate strong relationships with high-quality fruit throughout experiments, while lipids, amino acids, monosaccharides and organic acids showcase relationships with inferior quality fruit. Overall, maturity control is necessary in pomological experiments assessing the true impact of preharvest factors on fruit quality and metabolism.