Effects of Shading and Covering on  Sultana Seedles's 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 3 shading nets (0, 35, and 75% 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 90 days under cold storage (-0.5°C). Postharvest decay development and decreases in sensory quality were observed in unshaded grapes and in those covered with 35% shading net and later covered with life pack. Total soluble solids content, maturity index, and color value (C* and ho) were found lower in 75% 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 50 days. Consequently, in addition to delaying harvest time, PC or MG covers used after 35 % shading allowed higher quality and successful storage of grapes for an additional 90 days.