Fruit quality measurements and taste panel assessments indicated considerable latitude for programming harvest of ‘McIntosh’ apples. Ripening at 20°C was advanced by ethephon-auxin and delayed by succinic acid-2,2-dimethylhydrazide (SADH) and CO2. The rate of softening and acid catabolism at 0°C were not altered by the growth regulator treatments.
SADH suppressed ethylene production and CO2 suppressed both ethylene production and softening of ripening fruits held at 20°C. These effects were greatest in fruits not subjected to cold storage and declined linearly in fruits held 30, 60 or 90 days at 0°C. Neither SADH nor CO2 influenced acid loss at 20°C.