Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2006
Publication Date: 8/15/2006
Citation: Bai, J., Mattheis, J.P., Reed, N. 2006. Re-initiating softening ability of 1-methylcyclopropene-treated 'Bartlett’ and ‘d’Anjou’ pears after air or controlled atmosphere storage. Journal of Horticultural Science and Biotechnology. 81:959-964.
Interpretive Summary: European pears ripen in response to ethylene, a colorless, odorless gas produced naturally by fruit tissue. Management practices that limit the activity of ethylene also contribute to slowing of fruit ripening, a desirable outcome for fruit stored several months after harvest. Ethylene activity in pear fruit can be blocked by a 1-methylcyclopropene, another colorless gas that can greatly delay ripening in pear fruit. Because pears are typically eaten ripe, the application of 1-MCP can lessen the predictability of ripening making marketing of 1-MCP treated pears problematic. This work demonstrated ripening of pears previously treated with 1-MCP can be stimulated by periods at relatively warm temperature after storage. The utility of this process may allow better management of pear fruit quality after harvest.
Technical Abstract: ‘Bartlett’ and ‘d’Anjou’ pears treated with 300 nL L-1 1-methylcyclopropene (1-MCP), did not soften to eating quality within 7 d, a desirable ripening period. In this research, a preconditioning method was evaluated as a means to regenerate ripening ability of pears prior to marketing. Fruit treated directly after harvest with 300 nL L-1 1-MCP at 20 °C for 24 h were stored at -1 °C in regular air (RA) or a controlled atmosphere (CA). After 2-9 months of storage, fruit were preconditioned with 9 combinations of temperature (10, 15 or 20 °C) and time (5, 10 or 20 d) for each cultivar, storage atmosphere and storage duration. Preconditioned fruit were assessed for ripening ability following shelf life for 14 d at 20 °C. The ripening ability of 1-MCP-treated ‘Bartlett’ fruit recovered in response to many preconditioning combinations of 10-20 °C for 10-20 d as indicated by a decrease in flesh firmness to 27 N or lower. The preconditioning combinations of higher temperature and/or longer time accelerated the ripening response of the fruit. For ‘d’Anjou’ pears, no preconditioning combination was used that resulted in regenerating ripening of fruit. However, when 1-MCP dosage was < 50 nL L-1, ‘d’Anjou’ pears ripened in an extended shelf period, or within 7 d if the dosage was < 25 nL L-1 at 20 °C after 4 month storage in RA, although superficial scald was not completely controlled at these low dosages. Regeneration of ripening was concomitant with a substantial increase of ethylene productions. The results suggest that preconditioning regimes are cultivar, storage atmosphere and time dependent.