| With simulated drought stress in 10%(w/v) polyethylene glycol 6000 (PEG-6000), 41 accessions of high generation lines from intergeneric hybrids between B. napus and Rorippa indica and 32 Brassica napus released cultivars from different areas were treated during gemination period to inv estigate genetic difference of various genotypes of B. napus under drought stress simulated by PEG. The results showed that the survival ratio of most materials reduced
with an average of 96.11%, the seedling height, fresh weight per plant and vigor index also generally reduced, with the relative seedling height of 85.82%，relative fresh weight per plant of 75.65% and relative vigor index of 82.60%. But the taproot length increased significantly， the average relative taproot length reached 179.69%. The variation coefficient of relative survival ratio, relative taproot length， relative seedling height，relative fresh weight per plant and relative vigor index from 73 accessions of germplasm were 4.33, 20.10， 16.72, 18.73 and 18. 05，respectively. The drought toler-ance of different genotypes of B. napus had greater difference during gemination period. And the clustering analysis showed that 16 accessions of new gemmplasm from wide cross and 8 released varieties belonged to high tolerant drought re-sistance types，which could be used as drought tolerant gemplasm for genetic inprovement of B. napus. The comparison between the drought tolerance of 41 accessions of new gemplasm and that of 32 released cultivars during gemmination pe-riod showed that new germplasm from wide cross had better drought tolerance than released cultivars. |