Effects of GA3 and TDZ on fruit growth and quality of summer black grape.

The flower spikes of summer black grapes at full-bloom stage were respectively dipped into 30,40,50 mg /L GA3,and their fruit spikes were dipped into the combined solutions of 30,40,50 mg / L GA3 plus 1,3,5 mg / L TDZ two weeks after flowering. The application of 50 mg / L GA3(the first-step treatment) plus 50 mg/L GA3+ 5 mg / L CPPU(the second-step treatment) was taken as the control,and the effects of different hormone combination treatments on the fruit growth and quality of summer black grapes were studied. The results revealed that the application of 50 mg / L GA3at full-bloom stage plus 50 mg / L GA3+3 mg / L TDZ two weeks after flowering had the best effect,it not only increased fruit weight and soluble solids content,reduced the titratable acid content in the fruit,but also significantly promoted the improvement of the anthocyanin content in the pericarp,and its pericarp color indicators L,a,b and h values were significantly different from those in the control. In addition,the treatment with30 mg / L GA3at full-bloom stage plus 30 mg / L GA3+ 1 mg / L TDZ two weeks after flowering obtained significantly better fruit quality(except slightly lower single-fruit weight) than the control; the effect of TDZ was better than CPPU.