Dormex and Promalin affects fruit set and earliness of apricot (Prunus armeniaca) and plum (Prunus domestica) cultivars

Dormex (49% hydrogen cyanamide) and Promalin were applied to dormant trees of 'Tokaloglu' and 'Karacabey' apricot (Prunus armeniaca) and 'Papaz' plum (Prunus domestica) to break dormancy of flower and vegetative buds in 2001 and 2002. In both years, dormancy-breaking chemicals caused better budbreak, earlier flowering and harvesting than control trees. In apricots flowering was earlier by 2-5 days, in plums by 4-8 days. In both plum and apricot cultivars, 1% and 2% concentrations of hydrogen cyanamide gave better flower and vegetative budbreak ratio and fruit set. The highest budbreak and fruit set ratios were 87.67% and 85.33% in 'Papaz' plum treated with 2% hydrogen cyanamide, respectively. Promalin applications also caused better flower and vegetative budbreak and fruit set than control. Chemically-treated trees could be harvested 2-9 days earlier than control trees. All the chemical applications increased fruit weight in both plum and apricot.