Drought is the most important environmental factor that limit crop yield throught the world. About 96.7 precent of iran’s land is classified as arid and semiarid climates.canola is one of the most important oilseed in the world and its quality properties are affected by drought.The objectives of this research were to find the effect of different irrigation regimes on quality, yield and yield components of three canola cultivars(namely the hyola401, rgs001 and option500) .The experiment was conducted at cheshmeh khandan farm of semirom-isfahan using a randomized complete block with a split layout and replicated three times.Five irrigation regims (I 1 :70mm, I 2 :90mm, I 3 :110mm, I 4 :130mm, I 5 :150mm) were used as main plots and three canola cultivars were subplots.prolin precent,oil precent, relative water content precent,chrolophil precent,glycozinolat precent in grain and leaf were measured as quality parameters and plant height, number of pods,number of kernal per pod,leaf area index,pod length, weight of 1000 kernels,grain yield ,straw yield and harvest index as yield and yield component parametrers were measured.All yield components ,except pod length were decreased as drought levels increased. Oil, relative water content,chrolophil perecent decreased,while proli and glycozinolate precent increased severe drought occurred.Reduction of kernel weight , height and leaf area index of plant observed in severe drought.The highest variations in quality parameters were observed in I 5 treatment ,because of short and stressful flowering and filling period.These result show that oil accumulation was more sensitive to moisture deficit than protein accumulation.Grain yield was affected by irrigation regimes and reduced to35.4perecent in Hyola401 cultivar,50.6perecent in Rgs001 and 57.9 perecent in Option 500 cultivar. This showed that Option500 was more sensitive to moisture deficit, but. Rgs001cultivar had higher grain yield under sufficient water situation than other cultivars.
