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Conference paper - Peer-reviewed, 2010

Improving Quality and Storability of Apples by a Combination of Aluminum Reflective Mulch, Summer Pruning and Controlled Nitrogen Fertilization

Tahir, I.; Gustavsson, K. E.

Abstract

'Aroma' and 'Ingrid Marie' are the most important adapted apple cultivars to the Swedish conditions. Poor coloration at optimum harvest date and weak resistance to Pezicula malicorticis limit growers' ability to meet quality standards. In a three-year study at the Kivik research station, a novel orchard management model of; covering ground with aluminum ("reflective mulch" during 4 weeks before harvesting), cut thinning (to leave 6 fruits per cm(2) trunk cross-sectional area "TCSA" in July) and fertilizing according to leaf nitrogen-content, was applied to improve the quality and storage potential of these two cultivars. Tree yield and productivity were estimated. Apples were picked at pre-climacteric period and stored in three different storage methods (air: 21.0 kPa O-2 + 0.03 CO2 kPa, control atmosphere storage 2.5 kPa O-2 + 2.5 kPa CO2, and ultra low oxygen atmosphere 'ULO': 1.0 kPa O-2 + 2.0 kPa CO2), and on 2.0 degrees C, 90% RH for 22 weeks, before they were held in shelf life on 18 C, 90% RH for an additional week. Fruit color, firmness, soluble solids concentration (SSC), titratable acidity (TA) and antioxidant compounds (ascorbic acid, total phenols and anthocyanin) were investigated at harvest and after shelf life. The applied combined model significantly increased fruits color (lower hue angle and higher C-star value) in comparison with the standard managed trees. The applied combined model also caused higher yield by 25%, larger fruit by 16-17%, better flesh firmness by 10%, and higher TA/ SSC content by 25% in comparison with classic management. The fruit storability of these two cultivars was improved whereas higher resistance to bull's eye rot (Pezicula malicorticis) by 77% in 'Aroma' and 57% in 'Ingrid Marie' apples were achieved and the quality was better maintained, particularly in ULO storage. This novel management model increased anthocyanin and total phenol content in both cultivars.

Keywords

Malus domestica; ULO-storage; quality; aluminum groundcover; summer pruning; nitrogen fertilization

Published in

Acta Horticulturae
2010, Volume: 877, pages: 245-250
Title: Proceedings of the 6th International Postharvest Symposium : Antalya, Turkey, April 8-12, 2009
eISBN: 978-90-6605-613-8
Publisher: International Society for Horticultural Science

Conference

6th International Postharvest Symposium, APR 08-12, 2009, Antalya, TURKEY