Response of three strains of 'Gala' apples to high carbon dioxide prior tocontrolled atmosphere storage

The postharvest fruit quality of three strains ('Royal Gala: 'Imperial Gala ' and 'Crimson Gala') of apples was evaluated over two or three storage sea sons. To determine the influence of carbon dioxide treatment on storage qua lity, apples were stored in normal controlled atmosphere (1% O-2 & 1% CO2), or treated with 12% CO2 for 7 or 14 days prior to normal CA and evaluated after 90 or 150 days of storage. The use of 12% CO2 prior to storage helped to maintain firmness of 'Royal Gala' apples in 1 of 3 seasons. Firmness of 'Imperial Gala' and 'Crimson Gala' apples was not influenced by high CO2 t reatment, regardless of storage season. Other quality factors (color, solub le solids, acidity and carbohydrates) were not influenced to the extent tha t high CO(2)would be a viable option for the quality enhancement of 'Gala' apples during storage, regardless of strain. Use of normal CA maintained 'G ala' apple quality for 150 days of storage. Harvest date had a major influe nce on 'Gala' apple quality. A delay of one week reduced firmness and acidi ty, but enhanced color and content of sucrose, glucose and fructose in 'Roy al Gala: 'Imperial Gala' and 'Crimson Gala' apples.