Thesis
Modelling the key phenological stages and dormancy of individual grapevine cultivars
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102463
Abstract
The first part of this study included the estimation of base temperatures (Tb) and thermal time (DD) of 17 red and white grapevine cultivars (Vitis vinifera L.) that could potentially be used in predicting the consecutive development of three key phenological stages. The timing of occurrence varied among cultivars and stages. The Tb’s and estimated DD’s increased from budbreak to veraison, with average values of 7.2°C and 116 DD for budbreak, 8.7°C and 319 DD for bloom, and 11.0°C and 633 DD for veraison. Thermal time models were able to describe the phenological responses resulting from the weather variability among different years. The prediction errors ranged from 2 to 12 days, with the best performance for bloom. The estimated parameters can be used to predict phenology for helping select sites and cultivars, planning of labor and equipment, and timing of cultural practices. The second part of this study was an experiment to determine the occurrence of the para-, endo-, and eco-dormancy in grapevine cultivars Cabernet Sauvignon and Chardonnay during the 2013-2014 and 2014-2015 seasons. The temperature and daylength conditions involved in the induction and release of dormancy were analyzed, along with measurements of cold hardiness collected for the same period. Four chilling models were applied to determine cold requirements and the effect of cold exposure in reducing the time to budbreak. It was found that the onset of dormancy was the same for both cultivars and occurred at the same time for the both seasons. However, differences in dormancy release were observed between cultivars and seasons. The lack of differences in dormancy induction between years suggested that this process could be driven by photoperiod changes and is associated with the minimum rate of change in daylength, which coincided with the beginning of dormancy. Cold hardiness measurements indicated that the end of endo-dormancy, in which cold requirements were completed, matches with the beginning of the rapid acclimation process that occurs in November. Also, the dormancy periods identified and the chilling models allowed the estimation of minimum and maximum chilling requirements for the cultivars evaluated.
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Details
- Title
- Modelling the key phenological stages and dormancy of individual grapevine cultivars
- Creators
- Diana Maribel Zapata Rojas
- Contributors
- Gerrit Hoogenboom (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525077901842
- Language
- English
- Resource Type
- Thesis