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ARS Home » Pacific West Area » Wenatchee, Washington » Physiology and Pathology of Tree Fruits Research » Research » Publications at this Location » Publication #426061
Research Project: Enhancement of Apple, Pear, and Sweet Cherry Quality

Location: Physiology and Pathology of Tree Fruits Research

Title: Integrated effects of harvest timing, cooling regimes and controlled atmosphere on internal breakdown disorders of ‘Gem’ pears

Author
item Leisso, Rachel
item Turner, Janet
item McMurtrey, Shawn
item Klarer, Emmi
item Dowell, Kristal
item Wang, Eric
item Wang, Kevin
item Emmons, Jade
item DONG, YU - Qinghai University
item Michaud, Joseph
item Imler, Christopher
item Rudell Jr, David

Submitted to: European Journal of Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2025
Publication Date: 11/6/2025
Citation: Leisso, R.S., Turner, J.D., McMurtrey, S.B., Klarer, E.R., Dowell, K.M., Wang, E., Wang, K., Emmons, J.C., Dong, Y., Michaud, J.M., Imler, C.S., Rudell Jr, D.R. 2025. Integrated effects of harvest timing, cooling regimes and controlled atmosphere on internal breakdown disorders of ‘Gem’ pears. European Journal of Horticultural Science. 90:1. https://doi.org/10.1079/ejhs.2025.0026.
DOI: https://doi.org/10.1079/ejhs.2025.0026

Interpretive Summary: Internal breakdown is a postharvest flesh disorder of economic importance for 'Gem' pear. This research evaluated management practices to mitigate internal breakdown, with project outcomes indicating that disorder incidence can be mitigated by storing fruit in unmodified atmosphere (regular cold storage), cooling fruit rapidly and thoroughly after harvest, and by delaying controlled atmosphere (CA) storage until fruit is thoroughly cooled. Practices that exacerbate internal breakdown include rapid CA storage, high carbon dioxide levels in cold storage, or delaying cooling.

Technical Abstract: ‘Gem’ pear (Pyrus communis L.) is a relatively new European winter pear cultivar with good fire blight resistance. Unlike other common pear cultivars in a similar market class, ‘Gem’ fruit can be eaten without ripening, either at harvest or upon removing from cold storage, when still crisp and juicy, or can be expected to ripen to a buttery melting texture after a chilling requirement of 30-60 days in cold storage 30 °F. Previous research indicated ‘Gem’ could be stored in air 5 months and at least 8 months in controlled atmosphere (CA) with good quality retention, but commercial ‘Gem’ storage has proven more challenging, primarily due to an internal (cortex) physiological disorder termed internal breakdown and/or internal browning, with symptoms including lens-shaped cavities in the flesh similar to those found in CA-related disorders. In the present study, management strategies associated with lower internal breakdown and/or internal browning incidence include rapid and complete cooling of fruit after harvest, air storage at 30 °F, delaying CA (1.5% O2, <0.1% CO2) until fruit are thoroughly cooled, and fruit size less than 248 g. Conditions where fruit cooling is delayed (simulating potentially slower completion of thorough cooling in commercial setting), CA establishment is rapid (1 day after harvest), or CA CO2 levels were high (5% CO2), along with larger fruit size (greater than 248 g) were associated with higher disorder incidence.