Cornell University Apple Storage Workshop: Key Takeaways

Posted on by emh56@cornell.edu

The following are a few of the key takeaways from the Cornell Storage Workshop, held by the Watkins Lab in Ithaca on August 16, 2023.  Presentations by Christopher Watkins, Yosef Al Shoffe, Jennifer DeEll, and Mike Basedow.

Honeycrisp

Conditioning

Keep fruit at 50°F for 7 days and then store at 38°F.

  • Conditioning increases risk of bitter pit development but will decrease soft scald risk.

The use of PGRs (ReTain and Harvista) alone:

  • Slight benefit on firmness, and greener fruit with repeated and double rates.
  • Can maintain bitter pit susceptibility because it delays fruit maturation. Therefore, PGR use is not recommended in orchard blocks that are predicted to have high bitter pit risk.
  • Decreased risk of soft scald development.

1-MCP alone

  • Maintained higher acidity.
  • Decreased bitter pit, senescent breakdown.
  • Increased leather blotch in fruit treated with PGRs.
  • Increased core browning.

Preventing CO2 Injury in CA Stored Honeycrisp

If CA/DCA storage, conditioning at 50°F for one week recommended -then three options:

  1. DPA treatment
  2. Delayed CA/DCA –4 weeks looks pretty good
  3. Maintaining very low CO2 (<0.5%) levels in the storage.

Gala

Recommendations to control browning

  • Maturity is important. Fruit should be harvested when SPI is <4.0 and when IAD values are above 0.4.
  • PGRs applied at the correct timings are critical for long term storage of Gala apples. Do not store Gala without PGR treatment for more than 4 months.
  • Store Gala at 38°F (will benefit fruit without PGR treatment).
  • Postharvest 1-MCP is recommended.
  • 5% oxygen and 1% CO2 recommended for long term storage.
  • 2% oxygen and 1% CO2 for standard CA, although lower concentrations of either gas are ok.

NY-1

  • Harvest as early as possible to minimize browning risk, especially in CA.
  • Store at 38°
  • 1-MCP application is questionable for this variety – it does not always cause problems, but overall tends to enhance browning disorders. (Less of an issue in short term storage?)
  • Conditioning provides variable responses.
  • Low oxygen –DCA –may have promise but not for all disorders.
  • Use of DPA is worth considering, especially in normal CA (tentative recommendation)
  • Storage length is a major factor, although limited information.

NY-2

  • Another 38°F apple.
  • Best postharvest regime to date (usually) is conditioning/1-MCP/38F.
  • DCA is usually superior to CA following this practice (especially for core browning).
  • Block to block variation is concerning.

R10-45 ‘WildTwist’

More research is needed but recommendations to date are:

  • Recommended storage temperature is 38°F.
  • 1-MCP enhances internal browning.
  • Conditioning decreased flesh firmness in air storage and not in CA compared with continuous 38⁰F.
  • CA (2% O2/ 1% CO2) storage maintained flesh firmness and reduced flesh browning incidence compared with air storage.
  • DCA is recommended for long term storage, and has the additional advantage of maintaining good fruit flavor.

MAIA-1 ‘EverCrisp’

More research is needed but recommendations to date are:

  •  Recommended storage temperature is 38°F.
  • 1-MCP is not recommended as it can enhance flesh browning disorders.
  • ReTain is recommended to reduce watercore at harvest and physiological disorder development during storage.
  • Managing watercore is important to reduce physiological disorder development.

Ambrosia

Harvest Timings

Tends to harvest in the Empire window for long term storage. Background color should show more green than yellow at harvest.

  • Starch values for long term storage should be between 2.5 and 4. Starch 4-5 ok for short term, above 5 should market immediately.
  • IAD readings of 0.7-0.5 for longer storage, 0.5-0.3 short term storage, below 0.3 should be marketed immediately.
  • Target 18-19 lbs firmness, >11% brix.
  • Advanced maturity will lead to browning disorders, mealiness, and splits.

PGR Impacts

  • Harvista reduces internal browning. Postharvest 1-MCP reduces greasiness, improves firmness, maintains higher acidity and soluble solids. Inconsistent effects on internal browning.

Storage Regimes

  • Lower oxygen in storage leads to less internal browning. Very little at 0.6% and greatly reduced in 1.7% from 2.5%.
  • Less browning at 1% CO2 compared to 2%.
  • Conditioning for 1 week at 50°F also greatly reduced internal browning.
  • 4 weeks at 38°F before 33°F decreased internal browning. Did not impact firmness, but fruit were slightly greasy and slightly less acidic.

For a print copy of these recommendations, click on the link below.

https://blogs.cornell.edu/enychp/files/2023/09/Storage-Workshop-Takeaways-Watkins-edits-JD.docx