Thesis
Enhancing blueberry pollination through an improved understanding of pollen biology and implementation of in-field practices in western Washington
Washington State University
Master of Science (MS), Washington State University
2019
Handle:
https://hdl.handle.net/2376/100986
Abstract
Northern highbush blueberry (Vaccinium corymbosum) is an economically important crop in Washington State. Honey bees (Apis mellifera) are the primary pollinators in commercial blueberry. However, climate during the bloom period in western Washington is often unfavorable for pollination. Blueberry's short blooming period also limits the pollination and fertilization. Increased honey bee hive densities have been shown to promote pollination in 'Duke' blueberry, continued evaluations are needed to determine the point of diminishing returns and whether this strategy works in other cultivars. To overcome pollination difficulties, pheromones and attractants are widely applied by blueberry growers. Yet, their impacts on improving pollination are largely unknown and necessitates testing. The intrinsic factor of pollen performance should also be studied to define the optimal temperatures for pollen performance. The objectives of this thesis project are: (1) Characterize pollen performance among 'Aurora', 'Liberty', 'Draper' and 'Duke' blueberry at different temperatures (2, 7, 13, 18, and 24 °C); (2) Measure the impacts of modified honey bee hive densities (10 , 20 , and 25 hives/ha) on 'Duke' and 'Draper' blueberry pollination; and (3) Investigate the impacts of commercial pheromones and attractants (Bee-Scent, Honey Bee Magnet, Pollinate Pro, SureSet-Apex, and water and no-water controls) on pollination in 'Draper' blueberry. In the first experiment, pollen germination rate, tube length, and tube number/tetrad were observed. In the second and third experiments, honey bee activity was observed during the 2018 and 2019 pollination period. Fruit set, fruit quality and yield were also measured in 2018 (2019 results are pending). Results show that pollen germination and tube growth are greatest between 13-24 °C for 'Aurora', 'Duke', and 'Draper' and 13-18 °C for 'Liberty'. Honey bee hive density of 25 hives/ha increases honey bee visitation rates and fruit set and the diminishing point of return is likely higher than 25 hives/ha. Furthermore, evidence is marginal that application of pheromones and attractants improve pollination and overall production characteristics in blueberry.
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Details
- Title
- Enhancing blueberry pollination through an improved understanding of pollen biology and implementation of in-field practices in western Washington
- Creators
- Weixin Gan
- Contributors
- L. W. DeVetter (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525131201842
- Language
- English
- Resource Type
- Thesis