ABSTRACT
Atlantic cedar (Cedrus atlantica Manetti) was grown, grafting onto the rootstocks of 2 years old Lebanon cedar (Cedrus libani L.). The mixture of polystimulin (PS) growth regulators was used to determine the effects on graft success and subsequent growth during three growing seasons. Scion clones had no effect on grafts success. PS increased the graft success by 20% in comparison to controls. PS-treated grafts burst their buds 18-20 days earlier than control grafts and increased shoot elongation. The PS-treated grafts had 4-5 cm longer shoots than controls at the end of three growing seasons. Thus, this research indicates the significance of PS-application on graft success and subsequent shoot growth on Atlantic cedar. It suggested that use of PS-treated grafts was more profitable than controls. Polystimulins which were used in small doses contributed significantly to the metabolism of Atlantic cedar seedlings after grafting.