Wheat is a cereal of choice in most countries of the world and it is a staple food crop for more than 35% of the world population and also one of the widely cultivated crops in Syria. Constant efforts are therefore needed to boost its production to keep the pace with ever increasing population. But unfortunately, these efforts are seriously being hampered by a number of abiotic stresses among which is drought. Considerable attention over the years from plant breeders with the purpose of increasing the grain yield and to minimize crop loss due to unfavourable environmental conditions. Drought tolerance is a difficult trait to define as it encompasses a wide range of characteristics involving multiple genetic, physiological, cellular and biochemical strategies in the plant. Nine tolerant, moderately tolerant and susceptible durum wheat varieties were used in this experiment with major objective of examine the efficiency of the physiological system of these varieties under rainfed condition. Our result clearly showed significant differences between the three groups of varieties under study at vegetative and anthesis stage.