Effect of spraying Jasmonic acid and Girdling on growth, yield and improving fruits quality of Crimson seedless grapevine

THIS study was carried out during two successive seasons (2016 and 2017) in a private vineyard orchard at Boktares village, Agacenter, Dakahlia Governorate, Egypt. The experiment was conducted on 5-years-old Crimson seedless grapevine cultivar. The vines were grown in a clay soil under surface irrigation system and cane trained using pergolla trellis system. The aim of work was study effects of jasmonic acid and girdling on yield andfruit quality of Crimson seedless grapevine. Jasmonic acid wasused as a foliar application at rate (10, 20, 40 ppm) at two times: after berry set and begging berry color (at veraison stage) alone or combination with girdling begging berry color at) veraison stage). The Results showed that applications of jasmonic acid + girdling were effective for improving yield per vine, cluster weight, berry weight, volume, berry length and width, redberries & pink berries (as a visual assessment) soluble solids content, totalsugar, total anthocyanin in berry skin and total phenols while decreased total acidity and greenberry. Moreover, enhanced pruning wood weight, ripening wood and total carbohydrates in canes as compared with the controlduring both seasons. In addition increment internode length, internode thickness and trunk thickness.The promising results in this respect were obtained when the vines were sprayed with jasmonic acid 40 ppm+ girdling.