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United States Department of Agriculture

Agricultural Research Service

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Research Project: Commercial Testing of Early Scald Risk Assessment Tools

Location: Physiology and Pathology of Tree Fruits Research

Project Number: 5350-43000-006-31
Project Type: Trust

Start Date: May 01, 2013
End Date: Apr 30, 2016

Objective:
We have developed scald risk assessment biomarker-based tools that can be used to assess whether Granny Smith apples are at a higher risk for superficial scald during CA storage. We also found that storage outcome can be improved by adjusting storage based on information from these tools. Further validation is needed to test these tools’ utility under commercial conditions. We are continuing to validate this technology under laboratory, pilot, and commercial CA as well as using platforms that could be reasonable for a commercial QC laboratory. We propose continuing this work by testing multiple lots of Granny Smith in commercial conditions, validating additional gene expression biomarkers for risk assessment tools, and finding additional biomarkers that assess risk at harvest. We also plan to test these tools on Delicious apples. Proposed objectives complement or extend objectives outlined in our existing WTFRC project as well as our federal Specialty Crops Research Initiative (SCRI) project to continue to develop biomarker-based storage management tools for superficial scald and other key postharvest disorders of Honeycrisp and other important commercial cultivars. 1. Determine if risk assessment tools accurately represent scald risk in multiple commercial lots of Granny Smith apples. 2. Test scald risk assessment tools on Delicious. 3. Validate additional biomarkers for CA storage. 4. Begin search for biomarkers for at-harvest superficial scald risk assessment tools.

Approach:
Year 1 Validating SRAB tools for Delicious ‘Delicious’ apples will be harvested 1 month prior to commercial harvest. Fruit maturity and quality will be evaluated at harvest. Apples will be stored at 33 oF in CA at 1% or 5% O2 (all 1% CO2). Scald risk assessment biomarker levels will be monitored monthly. When biomarker levels indicate scald risk is increasing, a portion of the fruit stored at 5% O2 will be pulled down to 1% O2. Biomarker evaluation will continue to indicate if levels return to “normal” levels. Scald will be evaluated in all treatments at 0 and 7 days (at 68 oF) after 3, 6, and 9 months storage. Lot to Lot scald assessment in commercial Granny Smith and Delicious storages Multiple lots (5 from each of 4 storages) of Granny Smith and Delicious apples will be commercially harvested and stored (in organic CA rooms) and scald risk assessed monthly using biomarker-based scald risk assessment tools. Scald will be evaluated on all samples and then upon removal of each lot from storage. Tests will indicate whether tools accurately assessed the likelihood of scald development in both cultivars and in different commercial lots. Year 2 Lot to Lot scald assessment in commercial Granny Smith and Delicious storages Multiple lots (5 from each of 4 storages) of Granny Smith and Delicious apples will be commercially harvested and stored (in organic CA rooms) and scald risk assessed monthly using biomarker-based scald risk assessment tools. Scald will be evaluated on all samples and then upon removal of each lot from storage. Tests will indicate whether tools accurately assessed the likelihood of scald development in both cultivars and in different commercial lots. Year 3 At-harvest scald risk assessment ‘Granny Smith’ apples will be harvested 3 times (1 month prior to commercial, commercial, and 2 weeks following) from 5 locations with varying histories of scald susceptibility. Apples will be stored in air for up to 6 months. Peel tissue will be sampled at harvest and 2 and 4 weeks following harvest. Scald incidence and severity will be evaluated on subsets monthly.

Last Modified: 9/1/2014
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