2017 ASHS Annual Conference

This grower-supported apple maturity project focused on newer cultivars grown at the University of Maryland orchard in Keedysville, a warm, low-elevation site in southern Washington County, MD, and ‘Premier Honeycrisp’ and ‘Honeycrisp’ harvested from a 385 m (1250 ft) elevation orchard in Adams County, PA. Weekly maturity updates were distributed to growers through the Penn State Extension network as a collaboration of the Mid-Atlantic Fruit Consortium. Our goal was to provide pertinent information on fruit maturity ahead of the typical picking date for growers to the north. During August and September, 2016 apples matured earlier than normal. Once mature, they quickly tree-ripened. The hot, dry weather and full sun exposure of tall-spindle trees compressed the 2016 harvest window. After two blistering weeks in July, temperatures moderated briefly. That very brief reduction in temperature increased red color development, and ‘Premier Honeycrisp’ spot-picking began in mid-August. As ‘Gala’ fruit size increased, their stem-end cracking potential also increased. Fruit sugar levels and osmotic potential are greater at the stem end of ‘Gala,’ and so the small cracks developed there first. ‘CrimsonCrisp’ fruit were smaller, firmer, and redder than Honeycrisp with a slightly greater soluble solids content. Watercore was evident when ‘CrimsonCrisp’ fruit were immature. The ‘CrimsonCrisp’ fruit were quite firm, with a median value of 10.7 kg. The early maturation and rapid ripening continued with ‘Fuji’ and ‘Cripps Pink.’ There was a lot of weather-related peel damage to ‘Fuji’ fruit. Early spring weather was particularly hard on ‘Fuji,’ causing a lot of russeting. Later season heat and sunlight also damaged the fruit, with many fully-exposed fruits showing sunburn symptoms. Not only was the red color bleached, but there were also some necrotic lenticels. ‘Cripps’ Pink’ maturity was about 10 days ahead of schedule with starch just beginning to clear from the core region on October 6. No sunburn was noted on ‘Cripps Pink’ fruit. Measurement of Delta A values and starch pattern were also taken, and correlations between Delta A and starch pattern and their relation to storage scald susceptibility in ‘Fuji’ and ‘Cripps Pink’ were also calculated.