The effect of foliar application of methanol on productivity and fruit quality of grapevine cv. Flame Seedless

Abstract

Field experiments were conducted in 2002 and 2003 on 6-year-old grapevine cv. Flame Seedless. The content of chlorophyll a and b, carotenoids and total carbohydrates increased after methanol application. Foliar application of aqueous methanol was very effective increasing the number of leaves per shoot and leaf area. Furthermore, 30 % methanol increased significantly the number of stomata of developing leaves at the first application time (shoot length: 20-30 cm) while 10, 30, 40 and 50 % methanol solutions were more effective at the second application date (prebloom). Increasing the chlorophyll content, the leaf area and the number of stomata per unit leaf area by methanol application increased net productivity of vines. There was a highly significant positive correlation between total yield, chlorophyll and carbohydrates content. Generally, all methanol treatments significantly increased length and diameter of shoots and internode length at both application dates. Application of methanol increased total soluble solids (TSS), the TSS/acid ratio and total anthocyanins in berry skins but decreased total acidity. Most significant effects were obtained by spraying 30 % methanol at the two application dates.