Effects of 1-Methylcyclopropene on Firmness Loss and the Development of Rots in Apple Fruit Kept in Farm Markets or at Elevated Temperatures

Abstract

Many of the apples (Malus ×domestica) grown in the southeastern United States are sold to consumers through direct farm markets and roadside stands. Fruit in these markets may be exposed to high temperatures (>68 °F), which cause the fruit to ripen quickly, limiting their shelf life and consumer appeal and increasing their susceptibility to decay pathogens. Studies were undertaken in 2009 and 2010 to determine the effects of a 1-μL·L−1 postharvest 1-methylcyclopropene (1-MCP) treatment on the maintenance of flesh firmness and the incidence of rots in fruit held at elevated temperatures for up to 8 weeks. 1-MCP-treated fruit of three apple cultivars (Ginger Gold, Gala, and Golden Delicious) held in three retail farm markets in the southeastern United States maintained their firmness for 3 to 5 weeks. The firmness of non-treated ‘Ginger Gold’ fruit declined to less than 12 lbf after 1 week in each market, whereas the firmness of treated fruit remained greater than 16 lbf after 3 weeks. Treated ‘Gala’ fruit maintained their firmness at 14 lbf during 4 weeks in each farm market, whereas the firmness of non-treated fruit declined to less than 12 lbf after 2 weeks. The firmness of non-treated ‘Golden Delicious’ fruit declined to less than 12 lbf after 1 week in each farm market, whereas treated fruit maintained their firmness for up to 4 weeks. ‘Golden Delicious’ fruit treated with 1-MCP exhibited almost no loss of firmness during 4 weeks at 32, 50, or 70 °F, or even up to 8 weeks at 32 or 50 °F. The incidence of fruit rots increased with temperature, and 1-MCP reduced the incidence of fruit rots after 4 weeks at 70 °F in 2009 or after 8 weeks at 70 °F in 2010. These data show that 1-MCP may be of great benefit to producers who sell their fruit directly to the consumer by delaying the loss in firmness and reducing the incidence of rots in fruit kept at elevated temperatures.