Title: Regulating Ripening of 'Bartlett' Pears Using Preharvest Plus Postharvest Aminoethoxyvinylglycine (AVG) Author
Submitted to: Journal of Horticultural Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 30, 2008
Publication Date: N/A
Interpretive Summary: Bartlett pears in cold storage often ripen without uniformity. This results in some fruit rotting and being more susceptible to pathogens. AVG is an ethylene biosynthesis inhibitor that is often applied preharvest to reduce fruit drop and delay ripening. Because it is applied 4 weeks before anticipated harvest, environmental effects may affect its efficacy. Thus, we applied AVG to fruit after harvest by dipping the fruit in increasing concentrations, and examined fruit monthly for 4 months. The data indicated: 1) internal fruit ethylene, flesh firmness and peel color were all highly correlated, and measuring one variable could be used to predict the others; 2) concentration of AVG in the postharvest treatment was highly correlated with reduction in cumulative ethylene production; and 3) uniformity of ripening was improved with increasing dosage. Regulation and uniformity of ripening are important tools for marketing over an extended time, improving shelf-life and reducing pathogen susceptibility and development.
Technical Abstract: Variation in ripening uniformity of Bartlett (Pyrus Communis) pears in cold storage may be a problem in some years because of factors such as lack of chilling hours during winter, protracted anthesis and insufficient labor at harvest. On large orchards, such variation makes harvest timing very difficult. Use of ReTain (aminoethoxyvinylglycine, AVG, Valent Bioscience, Walnut Creek, CA) applied preharvest has mitigated this somewhat by delaying maturity development in treated blocks, thereby providing multiple harvest windows. To further regulate ripening of ReTain-treated Bartlett pears in cold storage, fruit were treated immediately after harvest with AVG at 0, 66, 132 or 264 mg l-1 and placed in regular storage at -1 ºC. Internal ethylene concentration (IEC) of individual fruit was measured at harvest and monthly thereafter for 4 months. Cumulative ethylene production showed a strong negative correlation with concentration of AVG in the postharvest dip. Treating Bartlett pears after harvest with AVG is appears more efficacious in reducing ripening variability during regular storage such that subsequent increase in ethylene is both consistent and predictable.