Abstract:

To investigate the impact of rachis smearing treatment in different concentrations of GA₃ (gibberellic acid) on the fruit quality of five domestic self-bred grape varieties, and to determine the optimal GA₃ concentration for each variety, an experiment was conducted to provide practical guidance for practical production. The five grape varieties were ‘SP522’, ‘Huozhou Heiyu’, ‘Gebi Xinxiu’, ‘Wuhe Cuibao’, and ‘Ruidu Cuixia’. Rachis of these grapes were smeared in petroleum jelly containing 0 mg/L (control), 0.5 mg/L, 2 mg/L, and 5 mg/L of GA₃. The results showed that under the 0.5 mg/L GA₃ treatment, the appearance quality indicators, cluster weight, and berry weight of ‘SP522’, ‘Huozhou Heiyu’ and ‘Wuhe Cuibao’ grapes were significantly higher than those of the control (CK) and other treatments. When treated with 2 mg/L GA₃, the tensile strength and hardness of ‘SP522’, ‘Huozhou Heiyu’ and ‘Ruidu Cuixia’ grapes reached their maximum values. The cluster weight of ‘Gebi Xinxiu’ and ‘Ruidu Cuixia’ grapes increased under the 5 mg/L GA₃ treatment, and the solid-to-acid ratio of ‘SP522’, ‘Wuhe Cuibao’, and ‘Ruidu Cuixia’ grapes was higher than control and other treatments. Notably, under the 5 mg/L GA₃ treatment, the fruit cracking rate of ‘Wuhe Cuibao’ grapes decreased by 37.38% compared to the control after soaking for 24 hours, and the tensile strength and hardness of ‘Gebi Xinxiu’ grapes reached their maximum.

Key words: grapes, gibberellin, fruit quality, rachis applying, fruit cracking rate, hardness, self-bred grape varieties