To investigate the effects of different seedless treatments on grape coloring and fruit quality, Vitis vinifera × Vitis labrusca cv. ‘Jumeigui’ were treated with different concentrations of forchlorfenuron (CPPU) (0.5, 1 and 1.5 mg/L), thidiazuron (TDZ) (0.5, 1 and 1.5 mg/L), and 6-benzyladenine (6-BA) (10, 20 and 30 mg/L) in combination with 18 mg/L gibberellic acid (GA₃) during the seedless-fruit-setting period. After the grapes ripened, multiple quality indicators were measured to analyze and evaluate the effects of different treatments on the fruit coloration and quality of ‘Jumeigui’ grapes. The results showed that increasing concentrations of CPPU and TDZ gradually reduced the comprehensive fruit quality of ‘Jumeigui’ grapes. The treatments with 18 mg/L GA₃ + 0.5 mg/L CPPU/TDZ were relatively effective in improving the comprehensive quality of ‘Jumeigui’ grapes. With increasing concentrations of 6-BA, the comprehensive effect initially increased and then decreased. The treatment with 18 mg/L GA₃ + 20 mg/L 6-BA resulted in a soluble solids content of 20.03% and a coloring index of 4.10, demonstrating the best overall improvement in the comprehensive quality of ‘Jumeigui’ grapes. Based on practical production considerations, it is recommended to apply 18 mg/L GA₃ + 20 mg/L 6-BA during the seedless-fruit-setting period of ‘Jumeigui’ grapes to enhance coloring effects and improve fruit quality.

Biostimulants have been increasingly investigated as eco-friendly alternatives to synthetic fruit enlargement agents in horticulture. In this study, two commercially cultivated kiwifruit cultivars, Zhongmi No. 2 and Jintao, were used as experimental materials. Three biostimulant products with distinct functional compositions were investigated: Benefit PZ (BPZ), which is rich in potassium humate and organic nitrogen; Shengcai A (SCA), containing amino acids and trace elements; and Puluosaiting (PLST), a natural seaweed extract–based formulation rich in bioactive compounds. Their effects on fruit development and internal quality attributes were compared with those of two fruit enlargement agents, 6-benzylaminopurine (6-BA) and forchlorfenuron (CPPU). Field experiments were conducted in two orchards located in Dancheng and Xixia, Henan Province, China, and treatments were applied during early fruit development. Growth traits (longitudinal and transverse diameters, single-fruit weight and firmness) and quality indicators (Soluble Solids Content, Titratable Acidity and Dry Matter Content) were measured at commercial maturity. CPPU and 6-BA substantially increased fruit size and weight compared with the control, whereas biostimulants produced moderate improvements without excessive enlargement. Notably, biostimulant treatments consistently enhanced internal quality attributes, indicating their potential to improve fruit quality without the drawbacks of excessive enlargement. Environmental and management differences between sites may also have contributed to treatment variability. These results suggest that biostimulants can improve internal quality traits while avoiding excessive fruit enlargement, representing a promising option for sustainable kiwifruit production.