Effect of Gibberellic Acid and Paclobutrazol on the Incidence of Primary Bud Necrosis in cv. Shiraz (Vitis vinifera L.)

Abstract

Experiments were conducted on cv. Shiraz vines (Vitis vinifera L.) to evaluate the effect of gibberellic acid and paclobutrazol on the incidence of primary bud necrosis (PBN). An application of gibberellic acid (100 mg/L⁻¹) one week before flowering, at flowering, and one week after flowering increased the incidence of PBN. The growth retardant paclobutrazol (100 mg/L⁻¹) decreased the incidence of PBN when applied one week before and after flowering. Shoot length and cane diameter were significantly greater than controls following application of gibberellic acid. These results suggested a strong relationship among shoot vigor, gibberellins, and PBN.