In order to determine the impact of hydropriming on germination characteristics of three canola cultivars under drought and salinity stresses, an experiment was conducted in 2012 at research laboratory in Bu-Ali Sina University as a factorial experiment in CRD with 3 replications. In this experiment, three factors were examined including canola cultivars (Hayola 401, Hayola 308 and RGS 003), seed hydropriming and similar osmotic potential levels by PEG-6000 and NaCl (-2, -4,-6, -8 and -10 bars) plus zero osmotic potential using by distilled water as third factor. Results revealed that in both stress, all measured traits except allometric coefficient (root:shoot length ratio) were decreased by reducing osmotic potential. Also at -8 and -10 bars of PEG all traits except germination percentage and germination index were zero. Hydropriming increased germination percentage especially under drought stress. The Hayola 401 displayed highest increase in germination percentage by hydropriming as compared with its noprimed treatment (24.6 % vs 11.5 and 11.18 % in RGS003 and Hayola 308 respectively). In all cultivars and osmotic potentials, hydropriming increased coefficient of velocity of germination about 6.5 and decreased mean germination time by 5.5 %. Highest mean germination time was achived in Hayola 308 at -10 bars in PEG (3.06 days). Germination index fluctuations by drought stress were more than salinity stress that indicate drought stress in lower potentials had been more harm to germinability than salinity stress. Also root and shoot length were reduced more in PEG than NaCl solution. However hydropriming in RGS003 and Hayola 308 at -6 bars in PEG caused increase in root length by 148 and 102 % respectively. Allometric coefficient of primed seeds of all cultivars in both stress medium increased up to -4 bars. Vigor index was better in NaCl than in PEG at the equivalent osmotic potentials and in Hayola 401 at -10 bars of NaCl the vigor index was increased about 231% compared with its noprimed.
