Deyman, K. L., Chiu, G., Liu, J., Brikis, C. J., Trobacher, C. P., DeEll, J. R., Shelp, B. J. and Bozzo, G. G. 2014. Effects of elevated CO₂ and 1-methylcyclopropene on storage-related disorders of Ontario-grown Empire apples. Can. J. Plant Sci. 94: 857-865. The impact of 1-methylcyclopropene (1-MCP) application on CO₂-induced physiological injury in Empire apple fruit during controlled atmosphere storage was assessed over a 3-yr period using an experimental design involving multiple treatment replicates. Fruit harvested at optimal maturity from one or two orchards were treated with or without 1 µL L^-1 1-MCP, then chilled at 0 or 3°C under various CO₂ partial pressures (5, 2.5 or 0.03 kPa CO₂) in the presence of 2.5 kPa O₂ for up to 46 wk using a split-plot design. Fruit were sampled periodically for assessment of flesh browning and external peel injury. The maximal incidence of external CO₂ injury varied from 15 to 100% over the 3 yr, and the most rapid development of this disorder was evident at 5 kPa CO₂. The incidence of external CO₂ injury as a function of storage time was influenced by orchard location and storage temperature. Moreover, the incidence of flesh browning at 0°C and 5 kPa CO₂ was influenced slightly by orchard; this disorder was never higher than 30%, and the impact of elevated CO₂ was inconsistent across years. Notably, there was no evidence for negative effects of 1-MCP on the incidence of storage-related disorders.