Dissertation
Abscission, storability, and fruit quality of mechanically harvested fresh market stem-free sweet cherry
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2009
DOI:
https://doi.org/10.7273/000006011
Abstract
A prototype mechanical sweet cherry harvester has been developed by the USDA in response to industry's need to improve labor efficiency. Commercial acceptance of the harvest system will require knowledge of cultural practices, stem-free fruit, and fresh market fruit quality. This research program sought to 1) identify effects of ethephon (2-chloroethyl phosphonic acid) on sweet cherry pedicel-fruit retention force and fruit quality, 2) study the effect of ethephon and mechanical harvesting on fruit storability, 3) study the role of the fruit pedicel on storability and weight loss, and 4) document metabolic changes in fruit tissue induced by ethephon. Ethephon applied at rates as low as 1.2 L ha-1 at 10 days prior to harvest was effectively reduced the pedicel-fruit retention force (PFRF) to ca. 400 g in 'Bing', facilitating mechanical harvest. Further, the cultivar 'Skeena' exhibits a naturally decline in PFRF to levels suitable for mechanical harvest. Conversely, 'Chelan' is non-responsive to ethephon and not suitable for mechanical harvest. The effect of the harvester on 'Bing' and 'Skeena' fruit quality is minimal in comparison to hand harvested fruit. Commercially assessed fruit cullage was ca. 23% for both harvest methods and cultivars. Generally, fruit storability was positively related to fruit size. In 2007, untreated stem-free 'Bing' lost 29% more weight than fruit with stems. However, the weight loss averaged ca. 6.5% for both stem-free and stemmed fruit in 2008. There was no difference in postharvest weight loss between 'Skeena' fruit with and without pedicels in both years. 'Bing' pedicels appear to be non-conductive to water transport. In contrast, 'Skeena' exhibited dye transport through the pedicel from the stylar incision in 2007 but not in 2008. Pedicels are susceptible to higher rates of browning, particularly in response to refrigeration in the commercial cold chain. Finally, metabolic profiling of ethephon-treated fruit reveal metabolic shift in simple sugars, malic acid, and color (cyanidin 3-glucoside/korumanin). Overall ethephon had little effect on quality. In general, effects of mechanical harvest are minimal upon fruit quality and storability showing promise for stem-free fresh market sweet cherries.
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Details
- Title
- Abscission, storability, and fruit quality of mechanically harvested fresh market stem-free sweet cherry
- Creators
- Erick David Smith
- Contributors
- Matthew David Whiting (Chair)David Robert Rudell (Committee Member) - Washington State University, Department of HorticultureAmit Dhingra (Committee Member) - Washington State University, Department of HorticultureCarter Clary (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Horticulture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 191
- Identifiers
- 99901055027401842
- Language
- English
- Resource Type
- Dissertation