Commercial Ripening of Cannery Pears with Ethylene

`Bartlett' pears (Pyrus communis L.) were harvested and ripened with and without ethylene in standard field bins at a commercial cannery. Mean firmness and firmness uniformity within a bin was evaluated for ethylene- and nonethylene-treated fruit. Uniformity of firmness among pears within a bin increased as ripening progressed. Applying 100 ppm (10 Pa) of ethylene gas during the first 24 hours of commercial ripening accelerated ripening of `Bartlett' pears held in standard field bins. Improved firmness uniformity would therefore be expected in ethylene-treated fruit commercially ripened to a lower firmness than untreated fruit otherwise ripened and processed at a higher firmness—the improved firmness uniformity was due to the lower firmness and not a specific effect of ethylene on ripening uniformity. When fruit were cold-stored for 20 days at 32 °F (0 °C) before ripening, the mean firmness and firmness uniformity of fruit exposed to ethylene during initial ripening was no different than nonethylene-treated fruit. Results from this study also indicate that fluctuations in ripening room air temperature, under some conditions, might increase firmness variability between fruit within a standard field bin.