Induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ Pears by temperature and ethylene conditioning

Abstract

Methods were tested for rapid induction of ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ pears in order to facilitate early marketing. Fruit of each cultivar were harvested at the onset of maturity and conditioned to develop ripening capacity by exposure to 100μLL−1 ethylene at 20°C for 0, 24, 48, or 72h, followed by varying durations of temperature conditioning at −0.5 or 10°C. Ripening capacity was tested by measuring fruit firmness after 7d at 20°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. With temperature conditioning at −0.5°C only, ‘Packham's Triumph’ pears needed 45d to develop ripening capacity, while ‘Gebhard Red D’Anjou’ pears were not capable of fully ripening after 60d, the longest duration tested. Using ethylene only, 72h exposure was necessary to develop full ripening capacity in both cultivars, and adequate shipping firmness was maintained. Using temperature conditioning at 10°C, ripening capacity in ‘Packham's Triumph’ and ‘Gebhard Red D’Anjou’ developed within 10 and 20d, respectively, but shipping firmness in ‘Gebhard Red D’Anjou’ was compromised at 20d. In both cultivars, 24 or 48h in ethylene followed by 5d at 10°C induced ripening capacity while maintaining adequate shipping firmness.