اثر پاکت‌گذاری بر صفات کمی و کیفی میوه دو رقم سیب (Malus domestica Borkh) ‘فوجی’ و ‘گرانی‌اسمیت’

Apple fruit color is determined by the amount of pigments in its peel which is directly affected by sunlight.  A method for improving apple fruit color is bagging. In present study, the effect of bagging and its optimum removing time was investigated on the amount of peel pigments and other fruit quantitative and qualitative characteristics for Fuji and Granny Smith apples. The experimental treatments were, no bag (control), debagging 7 and 14 days before harvest, and keeping the bag until harvest time. At the end of experiment, the amount of pigments, total soluble solids, titratable acidity, pulp phenol, peel phenol, antioxidants percentage, fruit weight and volume were measured. The results showed that in debagging 7 and 14 days before harvest treatments, the amount of anthocyanin and soluble solids statistically increased as compared with control; however other measured characteristics were significantly reduced in both apple cultivars. The maximum amount of fruit anthocyanin (60.96 mg/g fresh weight) belonged to Fuji cultivar in 14 days treatment and the least amount of fruit anthocyanin (1.64 mg/g fresh weight) belonged to Granny Smith cultivar in zero-day treatment. The highest amount of fruit chlorophyll a (5.09µgr/lit) was observed in control fruit and the lowest amount of fruit chlorophyll a (3.94 µgr/lit) was observed in 14 days treatment. The decrease of chlorophyll amount is a positive characteristic for the Fuji and a negative one for Granny Smith. Therefore, bagging and 14 days before harvest debagging treatment increased the amount of anthocyanin and decreased chlorophyll which resulted in Fuji cultivar better coloring and reducing the green color quality of Granny Smith cultivar.