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Thesis
Utilizing a Non-Destructive Approach to Improve Uniformity of Phase 2 Fruit Samples in the Washington State University Apple Breeding Program
Washington State University
Master of Science (MS), Washington State University
2023
DOI:
https://doi.org/10.7273/000006390
Abstract
The Washington State University Apple Breeding Program (WABP) is a conventional breeding program composed of three phases of selection. In the second phase (Phase 2), five replicate trees are evaluated for several years at three geographically diverse sites in the State of Washington. Phase 2 accessions are typically harvested over three picks using subjective maturity assessments that include change in the background color and starch degradation. Comprehensive evaluation of new apple (Malus domestica Borkh.) selections requires uniform samples of fruit and multiple years of data. Lack of information regarding optimal harvest date, accompanied by limited fruit and variable maturity throughout the canopy can lead to large within-sample variation of maturity in Phase 2 samples, as subjective methods do not ensure collection of uniform samples. The Delta Absorbance meter is a non-destructive portable device used to estimate maturity by measuring the index of absorbance difference (IAD) of fruit (IAD = A670nm – A720nm). Typically, IAD is applied in commercial varieties to identify variety-specific harvest windows, track fruit ripening, and sort fruit postharvest. With the rapid turnover and limited fruit availability in Phase 2 accessions, IAD was incorporated into the WABP harvest protocol to test whether IAD could be used to guide harvest without developing a model. With an IAD corresponding to a specific starch index rating, accessions were harvested using IAD-guided sampling. Coefficient of variation (CoV) was used to calculate within-sample variability. In 15 out of 26 samples, within-sample variability of IAD was reduced using IAD-guided sampling. Sample variability was also determined using the destructive trait measures of starch, soluble solids content, titratable acidity, and firmness. CoV of IAD-guided samples was reduced compared to non-IAD-guided samples in IAD at-harvest and three or more destructive trait measures after storage in six, nine, and seven out of 26 samples in in picks 1, 2, and 3, respectively. However, reductions of within-sample variability were accession, site, pick, and trait specific. A strong effect of accession and site was observed in all traits. IAD-guided sampling is currently being implemented as a supplementary measure during harvest of WABP Phase 2 accessions.
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Details
- Title
- Utilizing a Non-Destructive Approach to Improve Uniformity of Phase 2 Fruit Samples in the Washington State University Apple Breeding Program
- Creators
- India Amy Cain
- Contributors
- Kate Evans (Advisor)Carolina A. Torres (Committee Member)Sara Serra (Committee Member)Soon Li Teh (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Agricultural, Human, and Natural Resource Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 171
- Identifiers
- 99901087840101842
- Language
- English
- Resource Type
- Thesis