Pre- and post-harvest γ-aminobutyric acid application in relation to fruit quality and physiological disorder development in ‘Honeycrisp’ apples

γ-Aminobutyric acid (GABA) can accumulate in apple fruit response to stress, but little is known about the responses of GABA treatments. The hypothesis that would inhibit physiological disorder development ‘Honeycrisp’ apples has been tested a three-year study. In 2015, trees were sprayed with 40 mM 2 and 4 weeks before harvest, harvested stored at 0.5 °C, chilling injury-inducing temperature, or 3 for months. 2016, same concentration was on 1 harvest °C 5 2017 season, 0.12% CaCl2, either alone combination, 1, 2, harvest. Postharvest treatments also applied by dipping 100 and/or 2% CaCl2 Fruit air after week conditioning 10 continuously first two years, field had effect indices, inhibited soft scald depending spray timing. year 3, provided no benefit, combination CaCl2. Bitter pit incidence increased GABA/CaCl2 from one orchard block, times decreased second block. Treatment scald, bitter senescent breakdown extent as alone. Further research warranted better understand effects metabolism.