Location: Physiology and Pathology of Tree Fruits Research
Project Number: 2094-30600-001-022-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Jul 1, 2026
End Date: Jun 30, 2029
Objective:
1. Determine if anoxic treatment improves superficial scald and quality outcome during a 10-12 month cold chain.
2. Determine whether other scald mitigation inputs can be leveraged with anoxic treatments to improve/affect cold chain outcome.
3. Determine if relative changes of chlorophyll fluorescence reflect relative superficial scald control, black speckling incidence, and internal browning/pithy brown core.
Approach:
Expected reduced acceptance of ethoxyquin by many markets has driven efforts to develop new superficial scald control strategies for d’Anjou. Our ongoing work has demonstrated the effectiveness of ultra-low O2 (ULO, <1% O2) storage, squalane, and post long-term CA storage 1-MCP treatment for reducing scald, alone or in combination, to deliver fully ripened, clean pears following 9-10 month cold chains. Continuing challenges include controlling scald and a less common/consistent peel disorder, black speckling, during severe scald risk seasons. A short (2 week) anoxia (approaching 0% O2) treatment at the beginning of long-term CA storage can reduce or control superficial scald on Granny Smith apples without causing additional damage. We expect the same treatment may produce a similar outcome for d’Anjou, alone or in combination with other scald control tools. Potential risks include pithy brown core/internal browning and black speckling which has anecdotally been attributed to rapid atmosphere establishment and cold temperatures immediately following harvest. It is also unknown whether this treatment will improve superficial scald or impact other quality outcomes for d’Anjou as it does for Granny Smith. We propose to determine how the anoxia treatment will impact superficial scald and overall quality outcomes as well as work towards better understanding of why scald may be controlled during this period. The influence of delay time before establishing atmosphere, the impact of elevated CO2 during the anoxic treatment, effectiveness at different temperatures, and fruit lot will be tested. Chlorophyll fluorescence (Harvest Watch, DCA technology) and ethanol production will be monitored during and following these anoxia treatments to indicate relative “stress” during treatments among storage atmospheres, establishment delays, fruit lots, and other harvest and storage conditions.