effect of gibberllic acid, girdling, berry and bunch thining on the characteristics of fruit in grape cv. yaqooti

to evaluate effects of gibberllic acid, gridling, berry and bunch thining and their combination on fruit maturity, berry and bunch characteristics of grape cv. yaqooti an experiment was carried out using randomized complete block design with three replications in kavar, shiraz, iran, in 2010-2011 growing season. each experimental plot consisted of three vines. treatments included: t1: gibberllic acid spry (50 mg/l), t2: girdling, t3: berry thining, t4: bunch thining, t5: girdling + berry thining, t6: girdling + bunch thining, t7: girdling + gibberllic acid spry, t8: girdling + berry thining + bunch thining, t9: gridling + berry thining + gibberllic acid spry, t10: gridling + bunch thining + berry thining + gibberllic acid spry, and t11: control (no treatment). results showed that gridling promoted fruit maturity (8 days earlier than control) and the largest berries which was significantly (p<0.01) different from other treatments. therefore, trunk gridling was the most effective treatment to improve berry quality and maturity. fruit maturity was the latest in gibberllic acid treatment. hence, due to commercial importance of early fruit maturity of cv. yagooti, as a novel fruit, gibberllic acid treatment is not useful.