'Honeycrisp' Apple Maturity, Quality and Storage Disorders According to Interior and Exterior Tree Canopy Position

Apples are typically spot picked according to color and, therefore, indirectly according to canopy light exposure that affects fruit peel anthocyanins. We studied how interior and exterior canopy positions influenced fruit maturity and storage disorder incidence in 'Honeycrisp' apples grown in Maine (ME) USA, Minnesota (MN) USA and Ontario (ON) Canada, and harvested two to three times. Harvest maturity was more advanced in exterior compared with interior fruit. In both ME and ON, index of absorbance difference (I-AD) was higher for interior fruit compared to exterior fruit. Starch pattern index (SPI) was lower in interior fruit in ME and ON during the first harvest, but not the later harvests, and not in MN where starch breakdown was advanced. Internal ethylene concentration (IEC) at harvest, measured in ON only, was lower in interior fruit during the first harvest, but no difference occurred between the two positions in the latter two harvests. After four months of cold storage plus 1- and 7-d shelf tests, IEC (measured in ON only) was lower in exterior fruit. In all three sites, soft scald, soggy breakdown and bitter pit incidence did not vary between the canopy positions. Fruit were not conditioned to 10 degrees C and stored at 0.5 degrees C to allow for full development of chilling injury disorders. Canopy position altered fruit maturation and quality with no significant effect on soft scald or bitter pit.