Mature apricot trees (N. 'Amal' were sprayed on 10 Ih of January using three
different dormancy breaking agents i.e. zinc sulphate 5%, Dormex 1% (4go,{, Hydrogen
Cyanamide) and Urea5%. Zinc sulphate showed superiority over all other treatments
included as it was more effective in advancing bud burst by 17 and 12 days compared
to the control in the first and second season, respectively. Moreover, it induced the
highest bud opening percentage compared with the other two treatments or the
control. In addition, zinc sulphate significantly increased fruit set and yield. Also zinc
sulphate clearly increased fruit weight. diameter, firmness and T.S.S., meanwhile it
decreased fruit acidity when compared with other treatments and control.Concerning the effect of tested chemicals of severity powdery mildew disease on apricot, results revealed that all the used materials decreased the disease severity percentage when compared with the untreated trees. Zinc sulphate was Ithe
most effective in decreasing the infectlon with powdery mildew to 6.29 and 6.67%
accompanied with a high yieldJ tree in the first and second season, respectively.