Hydrogen cyanamide, mineral and vegetable oils on budbreak and fruit production of 'Royal Gala' apple trees

Abstract

The aim of this work was evaluate combinations of hydrogen cyanamide, mineral oil and vegetable oil on budbreak and fruit production of 'Royal Gala' apple trees. During 2001/2002 and 2002/2003 growth seasons different concentrations of hydrogen cyanamide (0.00; 0.29; 0.39; 0.49; e 0.59%) associated with mineral oil 3.2%, and hydrogen cyanamide 0.29% with vegetable oil 3.9% were tested in relation to budbreak in axillary and terminal buds, fruit set, production and mean fruit weight. The response of treatment with budbreak promoters was variable with chilling accumulation during autumn and winter season. The use of budbreak promoters increased the budbreak of axillary and terminal buds. The vegetable oil with hydrogen cyanamide showed lower performance than hydrogen cyanamide associated with mineral oil. The fruit set decreased with the increasing of hydrogen cyanamide concentration combined with mineral oil. The mineral oil 3.2% + hydrogen cyanamide 0.29% treatment showed the better results on budbreak and fruit production in both growth seasons evaluated.