Dissertation
ANALYSIS OF SPLITTING MECHANISMS IN GRAPE BERRY
Doctor of Philosophy (PhD), Washington State University
01/2018
Handle:
https://hdl.handle.net/2376/118112
Abstract
Fruit splitting is a disorder commonly seen in multiple horticultural crops. The causes of splitting are complicated, and the consequences can be detrimental for crop production. Grape (Vitis spp.) berry is a relatively simple model for splitting studies in fleshy fruits because of its spherical shape and simple structure. The present analysis of berry splitting was based on shell theories and fracture mechanics. In the injection test, pressurized water was injected into berries of different grape varieties at various developmental stages. The pressure in the berry was transmitted and dissipated by the berry tissues until it reached the skin. In the skin, the pressure became the tensile stress. The results showed the onset of berry ripening was the major turning point at which splitting resistance decreased rapidly. Since the soft flesh cells ceased to support the berry structure after the onset of ripening, the skin tissues became the sole stress-bearing structure in the berry. Moreover, Merlot grapes had higher splitting resistance than Syrah, Zinfandel, and Concord grapes. The cuticle thickness was measured but was not found to be sufficient to explain the varietal differences in splitting resistance. Physical and chemical manipulations of mechanical properties of cuticle and skin cell walls demonstrated that both cuticle and skin cell walls determine splitting resistance. A case study in eastern Washington showed that pre-veraison water stress can increase the splitting rate in the vineyard. Furthermore, the compact cluster architecture of Zinfandel was the major cause of berry splitting in this variety since the splitting rate in a cluster was clearly correlated with berry density. Taken together, the present results imply that the pressure required to split berries might come from both internal and external sources.
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Details
- Title
- ANALYSIS OF SPLITTING MECHANISMS IN GRAPE BERRY
- Creators
- Ben-Min Chang
- Contributors
- Markus Keller (Advisor)Norman R. Knowles (Committee Member)Bhaskar Bondada (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Horticulture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 161
- Identifiers
- 99900581424201842
- Language
- English
- Resource Type
- Dissertation