The effects of gibberellic acid and berry thinning applications on yield and quality properties of ergi̇n seedless grape variety

In this study, the effect of different doses of Giberellic acid (GA3) and berry thinning (TS) applications on yield and quality characteristics of 12-year-old Ergin Seedless grape variety grown on its own root was investigated. GA3 application was applied in 3 different phenological periods, i.e. before flowering, in full bloom and fruit set, at 10, 15, 20 and 40 ppm doses. Berry thinning was applied during fruit set. As a result of the study, the highest values in terms of grape yield and bunch weight are as follows: from K2 application (4308 g vine-1 and 478.7 g) in which applied TS and in two periods (before flowering and berry set) water was applied; from the K3 application (3913 g vine-1, and 434.8 g) where applied TS and water applied for three periods (before flowering+full bloom+berry set); It was obtained from GA2/2 application (3888 g vine-1 and 432.0 g), which was applied TS and applied GA3 (20 ppm before flowering+20 ppm in full bloom+40 ppm in berry set). It was determined that the effects of GA3 and TS applications and interaction on berry properties were not significant. It has been determined that there were important differences between GA3 applications in terms of must. The highest TSS (15.20%) and maturity index (20.15) were obtained from K1 application without water and TS. It was found that pH value was higher (3.30) than other applications in GA3/3 application where TS was applied and GA3 was applied (10 ppm in pre-bloom+10 ppm in full bloom+20 ppm in berry set). As a result, it was concluded that the GA3 effect may not be evident in varieties such as Ergin Seedless which has the quite large abortive seed. In later studies, it is recommended to investigate the deeper cluster tip cuttings for berry thinning with different GA3 concentrations and application times in this variety.