Regulation of stony hard peach softening with ACC treatment

Controlling the rate of fruit softening in melting-flesh peaches is a primary goal of the fruit industry. Stony hard (SH) peach varieties lack the ability to synthesize 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, which is required for fruit maturation. SH peaches thus have crisp flesh that remains firm during ripening. In this study, we developed a simple technique to stimulate fruit softening by a single spray application of ACC at a concentration of 10-20 mM, which was sufficient to allow ethylene synthesis and fruit softening. Higher concentrations of ACC increased ethylene production, and made the fruit softer. Ethylene synthesis was limited to the first 2-3 d after ACC treatment, after which fruit ceased softening and retained its remaining firmness. These results indicate that a single application of ACC solution can be used to regulate the process of fruit softening in SH peaches. (C) 2008 Elsevier B.V. All rights reserved.