Location: Physiology and Pathology of Tree Fruits Research
Project Number: 2094-43000-008-024-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 1, 2022
End Date: Aug 15, 2025
Objective:
1. Identify temperature/atmospheric combinations that reduce superficial scald without causing other disorders.
2. Determine what post-storage ripening and scald controls can be used following ultra low oxygen (ULO) controlled atmosphere (CA).
3. Evaluate tests that indicate disorder control effectiveness during ULO CA.
The “in-kind” contribution from WSU will be fruit quality analysis, valued at
$7,287 (wages and fringe) of direct cost.
Approach:
Controlled atmosphere using less than 1% O2 controls pear ripening and some peel disorders. Rapidly applied (pull down beginning less than a week after placement in storage) controlled atmosphere (CA) storage is the only effective ripening and
superficial scald control protocol currently acceptable for organically produced apples and pears. A roadblock to widespread use of ultra low oxygen, controlled atmosphere (ULO CA) to store d’Anjou pears is the risk of developing other disorders including black speck and internal browning or pithy brown core. Furthermore, scald can develop when poststorage cold chains last a month or more. ULO CA storage parameters that reduce black speck, internal disorder, and superficial scald risk without compromising ripening control or eating quality would remove an important barrier to safe, effective use of existing ULO CA technology. To accomplish this goal, we will test techniques we have collectively developed for apples and pears to overcome these and similar issues. We have found that storing pears at warmer temperatures following 1-Methycyclopropene (MCP) treatment, which has a similar impact on ripening as ULO CA, is a safe and effective way to provide fully ripe fruit to the consumer and may help reduce internal browning risk caused by this stress combination. Our work with apple shows that fruit stored in ULO CA can be treated with 1-MCP after storage (AP-16-101) to reduce scald and ripening and, with pear, indicates delayed treatment of up to 3 months with the new squalane superficial scald control drench can reduce or eliminate superficial scald if ULO CA was soon after placed in storage. We can monitor natural peel chemicals that may indicate whether the CA and room settings are controlling the disorders. Anticipated outcomes include additional protocols to control scald in an organic or crop protectant restricted cold chains using existing equipment without additional disorder risk, less risk of developing scald during distribution and retail, a potentially softer approach to applying 1-MCP later when it may allow pears to ripen easier, and potentially reduced energy costs.
