Integrated ethylene and temperature conditioning for induction of ripening capacity in 'Anjou' and 'Comice' pears

'Anjou' and 'Cornice' pears from three harvest dates were conditioned to develop ripening capacity by exposure to 100 mu L L-1 ethylene at 20 degrees C for 0, 24, 48, or 72h, followed by varying durations of temperature conditioning at -0.5 or 10 degrees C. Ripening capacity was tested by measuring fruit firmness after 7d at 20 degrees C after completion of conditioning treatments. Fruit firmness was also measured after conditioning but before ripening, and was designated "shipping firmness", indicative of the potential for the fruit to withstand transport conditions without physical injury. Ripening capacity in both cultivars developed more rapidly with later harvest date, increasing duration of ethylene conditioning, and increasing duration of temperature conditioning. Ripening capacity developed much more rapidly at 10 degrees C than at -0.5 degrees C. Useful durations of temperature conditioning at 10 degrees C were limited by fruit softening below acceptable values of shipping firmness. However, sequential combinations of ethylene and temperature conditioning at both -0.5 and 10 degrees C were identified wherein post-conditioning shipping firmness was acceptable. (C) 2013 Elsevier B.V. All rights reserved.