In order to develop nuclear energy uses in improvement of plants to dry condition and to investigate the effect of Gamma ray (800, 1000, 1200 gry and control) and PEG (-3, -6, -9 bar and control) on germination of two varieties of rapeseed (Sarigol and RGS003), an experiment was conducted in CRD design in factorial way at laboratory condition with 3 replication in 2011. The results obtained from analysis of data variance indicated that the effect of drought stress on germination percentage is significant (p<0.001). The results pertained to trait mean comparison for germination percentage on stress levels indicated that drought level with -3 bar osmotic pressure and 86.35 mean has the highest percent of germination and drought level -9 bar with 56.52 mean has the lowest one. The results of mean comparison in stress condition indicated that Gamma ray with 1000 gry dosage in all drought levels yields the highest mean which shows the beneficent effect of this dosage on resistance against drought stress. The results revealed that through application of drought stress and Gamma ray, Coefficient of Velocity of Germination on Sarigol in 1000 gry and -9 bar pressure and RGS003 in 800 gry and -9 bar pressure was in the maximum. Also Sarigol in all levels of Gamma ray in -9 bar had the most germination velocity in comparison with other drought levels. Finally it was identified that use of Gamma ray has a positive effect on resistance against the stress and 800 and 1000 gry was the best usable dosage.
