Combined treatment with gibberellic acid and thidiazuron improves fruit quality of ‘Red Dream’ grape cultivar

This study was conducted to investigate the effect of treatment conditions of plant growth regulators on the marketability of ‘Red Dream’, a triploid grape. In order to achieve the purpose of this study, gibberellic acid 3 (GA3) 100 ppm single use treatment group was set as a control group. In addition, the fruit characteristics expressed when cytokinins such as thidiazuron (TDZ) or forchlorfenuron (CPPU) 2.5 ppm or 5.0 ppm mixed with GA3 100 ppm were compared with the control group. Cluster weight was commonly higher in the mixed treatment of TDZ or CPPU than in the GA3 single use treatment, and it was found that the cytokinin mixed treatment could effectively induce the enlargement of ‘Red Dream’ berries. Although the harvesting period was slightly delayed compared to GA3 single use treatment in the case of mixed treatment of GA3 and TDZ or CPPU, there was no inhibition of coloration, soluble solid sugar content and functionality, which are important indicators of marketability. In particular, in the GA3 100 ppm + TDZ 5 ppm treatment group, where the enlargement of fruits was the largest, the occurrence rate of non-commercial berry was also found to be the lowest. Therefore, it is expected to contribute to strengthening the marketability of ‘Red Dream’ if such plant growth regulator treatment condition is applied during cultivation.