|CELEBREZZE, JOE - FORMER ARS EMPLOYEE|
|HANRAHAN, INES - WASHINGTON TREE FRUIT RESEARCH COMMISSION|
Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2020
Publication Date: 8/11/2020
Citation: McTavish, C.K., Tudor, E.M., Celebrezze, J., Mattheis, J.P., Rudell Jr, D.R., Hanrahan, I. 2020. Characterization of carbon dioxide-related storage disorder symptoms across multiple apple cultivars [abstract]. American Society of Horticulture Science Meeting. Paper No. 33564.
Technical Abstract: Carbon dioxide (CO2) sensitivity in storage contributes to annual apple losses due to both internal and external disorders. Often it is not known whether newer cultivars are sensitive to CO2 in storage or if conventional controlled atmosphere (CA) storage conditions will control these disorders. Also, the antioxidant diphenylamine (DPA), the most effective control to date is restricted or facing restriction in many markets. Consequently, we are testing a screening protocol to determine sensitivity for both external CO2 injuries typically seen on less ripe fruit along with internal CO2 injuries more likely present in more mature fruit, using DPA drenches to specifically control disorders related to CO2 sensitivity. Fifteen apple cultivars were harvested at two timepoints: (early) approximately 2-3 weeks before first commercial pick and (late) 1 week after first commercial pick. Apples were randomly selected, placed onto 2 trays per treatment, and treated with a 0.2% diphenylamine (DPA) dip or a control containing only diluted carrier and surfactant. All trays were put into CA storage for 4 months at 0.6 kPa O2 and 5 kPa CO2. After CA storage, apples were photographed, rated for internal and external disorders, and asymptomatic and symptomatic tissue sampled. External symptoms were diverse in appearance, including typical CO2 peel injury, characterized by a rough or “orange peel” texture, and/or soft scald, characterized by external brown peel patches with sharp margins. DPA drenching prevented the “orange peel” symptoms while not impacting what appeared to be soft scald. Internal disorders include cortex browning, defined by a radial pattern often accompanied by lens-shaped pits typical of CO2 injury, as well as soggy breakdown, characterized by non-radial patterns of injury with crisp margins. DPA largely eliminated radial browning, but had little effect on the crisp, non-radial patterns of soggy breakdown. Cultivars with a ‘Honeycrisp’ parentage generally had more incidence and severity of disorders than other tested cultivars. Next steps of this research are to metabolically analyze samples taken and test management schemes for the most efficient control of CO2 disorders.