A North American cooperative survey of 'Starkrimson Delicious' apple responses to 0.7% O2 storage on superficial scald and other disorders

Incidences of superficial scald and other storage disorders were recorded in two seasons, 1994 and 1995, for 'Starkrimson', a scald-susceptible strain of 'Delicious' apples (Malus domestica Borkh.) stored at 0 degrees C in air for 6 months and in 0.7% O-2 +/- 1.0% CO2 for 6 and 8 months at eight North American locations. Fruit from British Columbia (BC; 1994), New York (NY; 1994), Pennsylvania (PA; 1995), North Carolina (NC; 1994-95) and Oregon (OR; 1994-95), which were picked near starch index 2.0 on a 0-9 scale, were scald-free after storage in 0.7% O-2 +1.0% CO2 even though air-stored fruit had severe scald incidences. Low O-2 storage reduced, but did not eliminate scald on California (CA), Nova Scotia (NS; stored in 0% CO2), PA and Washington (WA) fruit in 1994, and NY fruit in 1995, However, 0.7% O-2 was ineffective in controlling scald on NS (stored in 0% CO2) and WA fruit in 1995. Immature fruit, delayed O-2 reduction, and failure to maintain the 0.7% O-2 +/- 1.0% CO2 atmosphere during the entire storage period decreased the effectiveness of 0.7% O-2 storage for scald control. Fruit from some locations were susceptible to skin purpling (OR), external and internal low O-2 injuries (NY, OR), and flesh breakdown (NY, OR). The 0.7% O-2 scald control protocol developed in BC shows promise for control of scald in PA and NC fruit and elsewhere except for NS (due perhaps to storage in 0% instead of 1.0% CO2). However, modification of the protocol may be required to optimize effectiveness of low O-2 Storage in some regions. (C) 1998 Elsevier Science B.V. All rights reserved.