Efficiency of pre-harvest application of 1-MCP (Harvista™ 1.3 SC) to delay maturation of ‘Cripps Pink’ apple fruit

Abstract The objective of this study was to evaluate the efficiency of pre-harvest application of 1-methylcyclopropene-α-cyclodextrin in concentrated magnesium sulfate solution (1-MCP; Harvista™ 1.3 SC) to delay maturation of ‘Cripps Pink’ apple fruit. 1-MCP was sprayed at 0, 75, 150, 225 and 300 mg L−1, seven days before the anticipated harvest time (DBAH). Aminoethoxyvinylglycine (AVG, 124 mg L−1, Retain®) was sprayed 28 DBAH, as a commercial control treatment. Fruit maturation was delayed by increasing 1-MCP concentration. 1-MCP at concentrations ≥ 150 mg L−1 delayed by six and 15 days the time for the fruit to reach the harvest firmness of 71.1 N and 66.7 N, respectively, compared to untreated fruit. Skin color changes (red color development and background degreening) were inhibited by increasing 1-MCP concentrations up to 300 mg L−1. The reduction of ethylene synthesis, and the loss of flesh firmness and starch content occurred by increasing 1-MCP concentrations up to 98.2, 134.5 and 182.3 mg L−1, respectively. The AVG treatment delayed ethylene production and skin red color development at harvest more markedly than the highest concentration of 1-MCP (300 mg L−1). However, both treatments (AVG and 1-MCP at 300 mg L−1) had late harvested fruit (28 days after spraying 1-MCP) with percentage of skin red color below 40%. The results show that 1-MCP delays maturity, but concentrations ≥135 mg L−1 do not improve its efficacy on preserving flesh firmness while might inhibit skin red color development in ‘Cripps Pink’ apples.