1-MCP is an inhibitor of ethylene perception that can delay fruit ripening and extend storage life. 1-MCP is marketed as SmartFresh™ for postharvest treatment and its use has become common practice in many apple-growing regions. 1-MCP reduces ethylene production and respiration rate, improves firmness and acidity retention, and controls senescent-related disorders in apples (DeEll et al., 2007; Fan et al., 1999a, 1999b; Watkins, 2007). 1-MCP has also been shown to increase the risk of stress-related disorders in apples; increased incidence of CO2 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).
Postharvest treatment of 1-MCP (1 μL·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.
The SmartFresh™ label in Canada was expanded in 2011 to allow up to four applications of 1-MCP (1 μL·L−1) within 240 d of harvest. Without such restrictions, the label in the United States was modified to include multiple applications in 2009. As a result, many storage operations are treating rooms with 1-MCP more than once during filling. This has provoked interest in the possibility that more than one application of 1-MCP could enhance the fruit quality benefits, but also potentially increase the development of disorders that are aggravated by 1-MCP.
Preliminary studies have shown that a second 1-MCP treatment after four or eight months of CA storage can improve firmness retention and reduce ethylene production and respiration rate in ‘Empire’ apples harvested at optimum maturity (DeEll and Murr, 2005). Response to 1-MCP was better when apples were held in low O2 CA (1.2 kPa O2 + 1.0 kPa CO2) than in standard CA (2.5 kPa O2 + 2.0 kPa CO2) at 2 °C, and the effects diminished with increased time after removal from CA before 1-MCP treatment. This same study found little effect of 1-MCP on ‘Empire’ and ‘Delicious’ apples when the treatment followed air storage instead of CA. DeLong et al. (2004) found no effect of an additional 1-MCP application after 4.5 months on ‘Cortland’ and ‘McIntosh’ apples held in air and CA storage, but the concentration of 1-MCP was less than that used commercially. Mir et al. (2001) found the most effective 1-MCP treatment frequency was once per week in ‘Redchief Delicious’ apples at elevated temperatures (5 to 20 °C). More recently, Watkins et al. (personal communication) showed little advantage of repeated 1-MCP applications at 4 or 7 d after harvest in addition to treatment 1 d after harvest.
There have been no scientific reports on the effects of rapid consecutive 1-MCP treatments on apples at harvest, simulating daily 1-MCP applications as storage rooms are loaded with fruit. The objective of this study was to investigate the effects of rapid consecutive postharvest 1-MCP treatments (1 and 2 d after harvest) on fruit quality and storage disorders in apples. ‘McIntosh’ and ‘Spartan’ apples were studied through long-term storage in air and CA. ‘McIntosh’ was also used to determine if two consecutive treatments of the label rate (1 μL·L−1 1-MCP) were equivalent to one application at double concentration (2 μL·L−1). There have been no scientific reports of 1-MCP treatment on ‘Spartan’ apples.
AgroFresh 2012 SmartFresh™ quality system, apple use recommendations. AgroFresh, Inc., Spring House, PA
Bai, J., Baldwin, E.A., Goodner, K.L., Mattheis, J.P. & Brecht, J.K. 2005 Response of four apple cultivars to 1-methylcyclopropene treatment and controlled atmosphere storage HortScience 40 1534 1538
Blanpied, G.D. & Silsby, K. 1992 Predicting harvest date windows for apples. Cornell Univ. Info. Bul. 221
DeEll, J.R., Ayres, J.T. & Murr, D.P. 2007 1-Methylcyclopropene influences ‘Empire’ and ‘Delicious’ apple quality during long-term storage HortTechnology 17 46 51
DeEll, J.R., Ayres, J.T. & Murr, D.P. 2008 1-Methylcyclopropene concentration and timing of postharvest application alters the ripening of ‘McIntosh’ apples during storage HortTechnology 18 624 630
DeEll, J.R. & Ehsani-Moghaddam, B. 2012a Delayed controlled atmosphere storage affects storage disorders of ‘Empire’ apples Postharvest Biol. Technol. 67 167 171
DeEll, J.R. & Ehsani-Moghaddam, B. 2012b Effects of preharvest and postharvest 1-methylcyclopropene treatment on external CO2 injury in apples during storage Acta Hort. 945 317 324
DeEll, J.R. & Murr, D.P. 2005 Ontario experiences with 1-MCP (SmartFresh TM) on apples. Proc. 101st Annu. Mtg. Washington State Hort. Assn. p. 159–161
DeEll, J.R., Murr, D.P., Porteous, M.D. & Rupasinghe, V.R. 2002 Influence of temperature and duration of 1-methylcyclopropene (1-MCP) treatment on apple quality Postharvest Biol. Technol. 24 349 353
DeEll, J.R., Murr, D.P., Wiley, L. & Porteous, M.D. 2003 1-Methylcyclopropene (1-MCP) increases CO2 injury in apples Acta Hort. 600 277 280
DeLong, J.M., Prange, R.K. & Harrison, P.A. 2004 The influence of 1-methylcyclopropene on ‘Cortland’ and ‘McIntosh’ apple quality following long-term storage HortScience 39 1062 1065
Fan, X., Mattheis, J.P. & Blankenship, S.M. 1999b Development of apple superficial scald, soft scald, core flush, and greasiness is reduced by MCP J. Agr. Food Chem. 47 3063 3068
Fawbush, F., Nock, J.F. & Watkins, C.B. 2008 External carbon dioxide injury and 1-methylcyclopropene (1-MCP) in the ‘Empire’ apple Postharvest Biol. Technol. 48 92 98
Jung, S.K. & Watkins, C.B. 2011 Involvement of ethylene in browning development of controlled atmosphere-stored ‘Empire’ apple fruit Postharvest Biol. Technol. 59 219 226
Lau, O.L. 1983 Effects of storage procedures and low oxygen and carbon dioxide atmospheres on storage quality of ‘Spartan’ apples J. Amer. Soc. Hort. Sci. 108 953 957
Meheriuk, M., Prange, R.K., Lidster, P.D. & Porritt, S.W. 1994. Postharvest disorders of apples and pears. Agr. and Agri-Food Canada Pub. 1737/E
Mir, N.A., Curell, E., Khan, N., Whitaker, M. & Beaudry, R.M. 2001 Harvest maturity, storage temperature, and 1-MCP application frequency alter firmness retention and chlorophyll fluorescence of ‘Redchief Delicious’ apples J. Amer. Soc. Hort. Sci. 126 618 624
Rupasinghe, H.P.V., Murr, D.P., Paliyath, G. & Skog, L. 2000 Inhibitory effect of 1-MCP on ripening and superficial scald development in ‘McIntosh’ and ‘Delicious’ apples J. Hort. Sci. Biotechnol. 75 271 276
Toivonen, P.M.A. & Lu, C. 2005 Studies on elevated temperature, short-term storage of ‘Sunrise’ Summer apples using 1-MCP to maintain quality J. Hort. Sci. Biotechnol. 80 439 446
Watkins, C.B. 2007 The effect of 1-MCP on the development of physiological storage disorders in horticultural crops. Stewart Postharvest Rev. 2:11. <http://www.stewartpostharvest.com>
Watkins, C.B. & Nock, J.F. 2005 Effects of delays between harvest and 1-methylcyclopropene treatment, and temperature during treatment, on ripening of air-stored and controlled-atmosphere-stored apples HortScience 40 2096 2101
Watkins, C.B., Nock, J.F. & Whitaker, B.D. 2000 Responses of early, mid and late season apple cultivars to postharvest application of 1-methylcyclopropene (1-MCP) under air and controlled atmosphere storage conditions Postharvest Biol. Technol. 19 17 32