Effects of Shading and Covering on ‘Sultana Seedless’ Grape Quality and Storability

This study aimed to determine the effects of different shading ratio and covers on “Sultana Seedless” table grape quality and storability. Grapevines were covered at the veraison stage with ۳ shading nets (۰, ۳۵, and ۷۵% shading), which were then replaced with covering materials including Polypropylene Cross-stitch (PC), Life Pack (LP) and Mogul (MG), just before harvest. Harvested grapes in all treatments were then kept for ۹۰ days under cold storage (-۰.۵°C). Postharvest decay development and decreases in sensory quality were observed in unshaded grapes and in those covered with ۳۵% shading net and later covered with life pack. Total soluble solids content, maturity index, and color value (C* and ho) were found lower in ۷۵% shaded grapes compared to unshaded plots. Effects of the tested applications on quality attributes either decreased or vanished during storage. All tested cover materials following shading nets could delay harvest for ۵۰ days. Consequently, in addition to delaying harvest time, PC or MG covers used after ۳۵ % shading allowed higher quality and successful storage of grapes for an additional ۹۰ days.

Keywords:

Late harvest , On-vine storage , Photon flux density , Post-harvest decay , Shading nets