The study was executed during two growth seasons (2007 – 2008 and 2008 – 2009) in Syria..Foliar spray by boron was applied during three stages namely; In the spring at the bud-burst; Before opening of flower buds and After Fruit Set. The study aimed at investigating the effect of foliar spray of organic and inorganic boron with tow concentrations ( 0, 250, and 500 ppm) for fruit set, yield and boron content in english Morello var. of Sour Cherry grafted on Mahaleb rootstock. Results showed that concentration ( 500 ppm) of organic boron had manifested better effects on fruit set (18.7%) and yield (17.9 kg/ tree) as compared to the control treatment and to treatment of boron (500 ppm) inorganic, which realize fruit set of 15.4 – 7.4% and yield of 13.8 – 6.3 kg/ tree respectively. Different treatments had shown good effect in boron content accumulation in flowers, leaves, set fruits and ripening fruits.

Key Words :Foliar Fertilization, Boron, Yield, Sour Cherry