Research Updates from the 101^st Annual Conference of the American Society of Horticultural Science (ASHS)

Cropload Affects Fruit Quality of Honeycrisp Apple - Terence L. Robinson and Christopher B. Watkins, Cornell University

A wide range of croploads (0-15 fruits per cm² of TCA, truck cross-sectional area) on 4- and 5-year old Honeycrisp/M9 trees were investigated for two years, by manual hand thinning soon after bloom. Fruit ripening and quality were evaluated at harvest, as well as after 5 months of storage in air at 38 and 33^oF. Cropload was negatively correlated with tree growth, return bloom, fruit size, fruit red color, fruit sugar content, fruit starch content, fruit firmness, fruit acidity, bitter pit, senescent breakdown, fruit rot, and superficial scald, while cropload was positively correlated with leaf blotch symptoms, fruit internal ethylene concentration at harvest, and soggy breakdown in storage. Overall, croploads greater than 10 resulted in no bloom the next year, as well as poor fruit size, color and flavor, but these fruit tended to have the least storage disorders. Moderate croploads (7-8) resulted in disappointing return bloom and mediocre fruit quality. For optimum quality and annual cropping, relatively low croploads of 4-5 were necessary.

Contamination of Apple Fruit with Diphenyl-amine during Storage - Charles F. Forney, Jun Song, and Michael A. Jordan, AAFC, Nova Scotia

Diphenylamine (DPA) residues have been detected on apples not treated with DPA and this is problematic in markets where DPA residues are not acceptable. Concentrations of DPA in the atmosphere of commercial storage rooms was monitored during the storage season and the adsorption of DPA onto wood and plastic bin material, plastic bin liners, foam insulation, and apple fruit was assessed. DPA was to found to volatize from treated apples and bins into the storage room air, where it was adsorbed onto storage room walls, bins, bin liners, and other apples. DPA was found in the atmosphere of storage rooms containing apples that were not treated with DPA. Wood and plastic bin material, bin liners, and foam insulation all had a high affinity for DPA and were determined to be potential sources of contamination.

Bioflavonoids of Apples: Effects of Genetic Variability, Fruit Parts and Processing - Vicky W. Lee, H.P. Rupasinghe, and Chung-Ja Jackson, University of Guelph

Apples are excellent sources of dietary phenolics, in particular flavonoids and chlorogenic acid, which are potent antioxidants that may play important roles in the prevention of chronic diseases. This study investigated the major phenolic profiles in eight Ontario-grown apple cultivars. Total antioxidant capacity (TAC), total phenols content (TPC), and flavonoids levels were the highest in Honeycrisp and red Delicious, moderate in Idared, Spartan, Granny Smith, and Cortland, and the lowest in Crispin and Empire. Apple peel contained 2 to 10-fold higher TAC, TPC, and 10 major flavonoids than the core and flesh tissue.

Effects of Postharvest Delay Before Application on Responses of Apple to 1-MCP - Chris B. Watkins and Jacqueline F. Nock, Cornell Univeristy

The effects of 1, 2, 3, 4, 6, and 8-day delays between harvest and 1-MCP treatment on McIntosh, Cortland, Jonagold, Empire, and Delicious apple quality stored in air for 2 and 4 months, and in CA for 4 and 8 months, were investigated. In addition, 1, 7, 14, and 21-day delays on Cortland, Jonagold, Empire, and Delicious quality were evaluated, after 5 months in CA. The data showed that responses of apple cultivars to 1-MCP can be affected by delay of treatment, but that within each cultivar the effects vary with harvest maturity, storage type, and length of storage. In terms of firmness retention, 1-MCP efficacy was acceptable up to a 7-day delay between harvest and treatment in Cortland, Jonagold, and Empire, and up to a 14-day delay for red Delicious.