Agroscope | 2013
Dynamic CA Storage of Organic Apple Cultivars
Gasser Franz, von Arx Kathrin, Agroscope Changins-Wädenswil Research Station ACW, Switzerland franz.gasser@agroscope.admin.ch
Objectives
Over three years, selected hot-water treated and non-treated organic apple cultivars (Topaz, Ariane, Otava) were stored under DCA-
conditions in order to examine whether hot water treatment has an impact on fruit stress during DCA-storage and if DCA-stored fruit retain quality better than ULO-stored fruit during long-term storage. Furthermore, organic fruit were compared to fruit produced under
“integrated production” conditions.
Results
• The critical oxygen concentration (anaerobic compensation point, ACP) during DCA-storage was not influenced by previous hot-water treatment nor by the production method.
• However, ACPvaried from year to year (e.g.: for Topaz 0.20kPa, 0.18kPa and 0.56kPa O2 over 3 years), showing that yearly fluctuations of climatic conditions during production may influence fruit behavior during storage.
• For Topaz and Otava, DCA had no positive effect on fruit quality compared to ULO conditions, whereas for Ariane, DCA stored fruit retained fruit firmness and acidity better compared to fruit stored under ULO conditions.
• Hot-water treatment did not affect fruit quality and the incidence of physiological disorders of DCA- stored apple.
• Fruit rot was affected by the cultivar, Topaz being the most susceptible cultivar and Ariane the most resistant to fruit rot.
• Organic fruit were susceptible to higher fruit rot during DCA-storage than IP fruit.
• Compared to ULO conditions, DCA did not reduce fruit rot.
Control of storage conditions (T, RH, O2, CO2)
Fruit physiological response
Stress:
Lowering of Oxygen level
Response: modified Chlorophyll fluorescence
Time course of RQ and F-α during dynamic CA storage of ‘Topaz’ apples (storage season 2011/2012, HT = hot water treatment)
Comparison of DCA-stored organic apples with and without hot water treatment with organic apples stored under ULO-conditions (control) over 3 years (R = after removal from storage, SL = after shelf life)
