Effect of Pre-bloom Sprays and Soil Drenches of Paclobutrazol on Growth, Yield, and Fruit Composition of ‘Roumi Red’ Grapes

Abstract

Trials were conducted using paclobutrazol (PP333) either as a foliar application or a soil drench to improve berry set and yield of ‘Roumi Red’ grapes (Vitis vinifera L.). Concentrations of 100 and 250 ppm (foliar applications) and 2 ml/vine as a ground application had no effect on either chlorophyll and carotenoid leaf content or physical and chemical properties of berries, other than cluster weight and number of berries/cluster, which increased significantly. Concentrations of 1000, 1500, and 2000 ppm and 4 ml/vine reduced shoot and internode length as well as °Brix, whereas physical and chemical properties of berries, bud fertility, chlorophyll, and carotenoid leaf content were increased. A carry-over effect was noticed the year following the year of application with concentrations of 750 ppm and 3 ml/vine or higher. Chemical name used: β[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

The Influence of Paclobutrazol on The Yield and Fruit Quality of Superior Seedless Grapevines

“…The yield of the untreated vines reached (8.2 -8.3 -8.4 kg) during the 2018/ 2019, 2019/ 2020, and 2020/2021 seasons, respectively. Our results are in agreement with those obtained by Fei et al, (2022) and Shaltout et al, (1988). Table (3) showed the berry weight (g.), height and diameter of Superior grapevines.…”