An-Najah Staff

The effect of two concentrations (2.5% and 5% v/v) of Dormex (e.i 49% hydrogen cyanamide), and potassium nitrate (5% v/v) on bud break, production and quality of Vitis vinifera L. 'Perlette' grape grafted on 'Richter 110' was studied. The experiment was conducted at the Agriculture Experimental Station, Department of Agriculture at Jericho in the Jordan Valley. The assigned concentrations of the chemicals were applied immediately after pruning. Each treatment was applied to 10 different vines: another 10 vines were sprayed with distilled water as a control treatment. After two months of application, significant bud break percent 87.7% was obtained using 5% Dormex application, followed by 5% potassium nitrate and 2.5% Dormex 'that resulted in 55.3 and 52 % bud break, respectively. Higher cluster number was obtained with 5% Dormex, however, average cluster weight was not significantly different among all treatments. Potassium nitrate at 5% resulted significantly in similar average production per vine compared to the Dormex treatments. All treatments gave higher average production per vine than the control. The total acidity of the berries was significantly higher with 5% potassium nitrate over the control, however, berries pH, brix, total soluble solids and specific gravity were not affected by the chemicals used.