1-Methylcyclopropene Concentration and Timing of Postharvest Application Alters the Ripening of ‘McIntosh’ Apples during Storage

Abstract

<jats:p>This study evaluated the effects of 1-methylcyclopropene (1-MCP) concentration (1000 vs. 625 ppb) and treatment delays (3, 7, and 10 days after harvest) on the ripening and incidence of storage disorders in ‘McIntosh’ apples from three harvest times in 2004. Apples were stored in air at 0 °C to 1 °C for 3 and 6 months or in controlled atmosphere (CA) storage at 3 °C for 6 and 9 months. Apples treated with 1-MCP and held in air or CA storage were firmer than those not treated, but this difference in firmness was less with later harvests, more delay before 1-MCP treatment, and longer storage time. Apples treated with 1000 ppb 1-MCP were often firmer than those treated with 625 ppb after 6 months of storage and/or 7 days at 22 °C. Ethylene and carbon dioxide (CO<jats:sub>2</jats:sub>) production were reduced in apples treated with 1-MCP, especially in fruit from the first harvest and those treated 3 days after harvest. Fruit treated with 1000 ppb 1-MCP showed a slower increase in ethylene production than those treated with 625 ppb during 14 days at 22 °C after storage. CO<jats:sub>2</jats:sub> production was the lowest in ‘McIntosh’ apples treated with 1000 ppb 1-MCP 3 days after harvest, but fruit treated with 625 ppb also exhibited lower respiration than those not treated. Storage disorders were most prevalent in ‘McIntosh’ apples stored for 6 months in air at 0 °C to 1 °C, whereas fruit from the first harvest treated with 1-MCP 3 days after harvest developed the fewest disorders. 1-MCP reduced the incidence of superficial scald, flesh browning, core browning, and senescent breakdown, while 1-MCP concentration and treatment delay had varying effects. This research has provided the basis for Canadian registration of SmartFresh<jats:sup>SM</jats:sup> use on apples at 1000 ppb 1-MCP and for the requirement that treatment be within 3 days of harvest.</jats:p>

Effects of Rapid Consecutive Postharvest 1-Methylcyclopropene Treatments on Fruit Quality and Storage Disorders in Apples

“…with previous results, in which all 1-MCPtreated 'McIntosh' from three harvest times exhibited firmness greater than 49 N after three and six months of air storage at 0 to 1°C (DeEll et al, 2008). After six months of CA storage, 'McIntosh' from the first harvest treated once with 1 mL · L -1 1-MCP were also softer than those treated once with 2 mL · L -1 1-MCP or treated twice with 1 mL · L -1 1-MCP (Table 3).…”

“…Core browning tends to be more prevalent in fruit that is high in nitrogen, large, shaded on the tree, or harvested after an extended period of cloudy, cool, or wet weather (Meheriuk et al, 1994). Single postharvest applications of 1-MCP typically reduce core browning in 'McIntosh', but this effect diminishes with advanced maturity at harvest time and 1-MCP concentrations below 1 mL · L -1 (DeEll et al, 2008;Watkins et al, 2000).…”

“…1-MCP has also been shown to increase the risk of stress-related disorders in apples; increased incidence of CO 2 injury or flesh browning has been found in 1- MCP-treated 'McIntosh' and 'Empire' apples (DeEll et al, 2003;Fawbush et al, 2008;Jung and Watkins, 2011). Efficacy of 1-MCP treatment depends on apple cultivar (Bai et al, 2005;Watkins et al, 2000), harvest maturity (DeEll et al, 2008;Toivonen and Lu, 2005), and temperature and timing of application (DeEll et al, 2002;Watkins and Nock, 2005). Effects of 1-MCP on 'McIntosh' apples are reduced in later harvests and with longer delays between harvest and treatment (DeEll et al, 2008).…”

“…Efficacy of 1-MCP treatment depends on apple cultivar (Bai et al, 2005;Watkins et al, 2000), harvest maturity (DeEll et al, 2008;Toivonen and Lu, 2005), and temperature and timing of application (DeEll et al, 2002;Watkins and Nock, 2005). Effects of 1-MCP on 'McIntosh' apples are reduced in later harvests and with longer delays between harvest and treatment (DeEll et al, 2008).…”

“…Postharvest treatment of 1-MCP (1 mL · L -1 ) has traditionally involved a single application soon after harvest. It is recommended that 'McIntosh' be treated with 1-MCP within 3 d of harvest for maximum effectiveness (AgroFresh, 2012;DeEll et al, 2008). This has been difficult for small growers with storages that can take 1 week or more to fill.…”