Effects of Preharvest Applications of Ethephon and 1-MCP to ‘Bing’ Sweet Cherry on Fruit Removal Force and Fruit Quality

Preharvest application of ethephon to ‘Bing’ sweet cherry ( Prunus aviumL.) trees consistently reduced fruit removal force (FRF) but also reduced fruit flesh firmness at commercial harvest. Treatment resulted in only minor effects on soluble solids concentration and titratable acidity. Red color development in fruit skin and flesh was stimulated by ethephon in some seasons. Pedicel color showed little response to ethephon and there were no effects of any treatment on fruit size. Holding sampled fruit for one or two weeks in cold storage typically resulted in fruits with higher firmness, possibly due to dehydration. Ethephon increased gum formation (gummosis) on treated trees in some, but not all, seasons. Applications of 1-MCP to sweet cherry trees within 3 days of ethephon treatment in 2003 counteracted ethephon-induced flesh firmness loss without inhibiting the reduction in FRF, but this response could not be reproduced in the following three years, despite the inclusion of various experimental sprayable formulations of 1-MCP at various concentrations, timings, spray volumes, types of sprayers and use of surfactants or other additives. Ethephon-induced changes in fruit quality may take place via pathways not regulated by 1-MCP binding or, on the other hand, binding of 1-MCP to active sites may be transitory or insufficient to initiate such changes.