Polymeric nano‐delivery of gibberellic acid enhances fruit quality, yield and pedicel strength in grapevine ( Vitis vinifera L.)

Abstract BACKGROUND Nanoparticulate systems offer an effective strategy for the targeted delivery of agrochemicals and for enhancing their efficacy. This study aimed to synthesize and characterize gibberellic acid (GA 3 )‐loaded poly( d,l ‐lactic‐ co ‐glycolic acid) nanoparticles (PLGA NPs) and to evaluate the effects of their application on the flower clusters of Vitis vinifera L. Thompson Seedless in terms of bunch and berry characteristics. RESULTS GA 3 ‐loaded PLGA NPs exhibited an average particle size of 217.7 ± 4.2 nm, a zeta potential of −16.2 ± 1.74 mV and a polydispersity index of 0.294 ± 0.015. The reaction yield, encapsulation efficiency and loading capacity were determined as 27.14%, 51.02% and 67.13%, respectively. Fourier transform infrared spectroscopy analysis confirmed the successful incorporation of GA 3 into the PLGA matrix, whereas release studies demonstrated that 65% of the encapsulated GA 3 was released within 96 h, followed by a markedly slower release. Field applications demonstrated that GA 3 ‐loaded PLGA NPs significantly increased cluster weight (104%) and length (67%) compared to free GA 3 treatment, whereas berry weight, length and width increased by 15%, 4% and 13%, respectively. The treatment also significantly enhanced total soluble solids and titratable acidity, indicating improved fruit ripening. Unlike conventional GA 3 applications, which may reduce pedicel detachment force in some cultivars, the nanoparticle formulation increased detachment resistance by 8% and 25% compared to the control and free GA 3 treatments, respectively, suggesting reduced risk of post‐harvest berry drop. CONCLUSION The findings provide the first evidence that GA 3 ‐loaded PLGA NPs can improve grape yield and quality parameters and highlight their potential as a promising and environmentally friendly approach for sustainable agricultural production. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.