Abstract:Drought in autumn has negative effect on germination and growth of rapeseed in Yangtze River valley. It is critical to identify drought tolerance resource in Brassica rapa for rapeseed breeding for tolerance against drought. The drought tolerance of five Brassica rapa accessions with different genetic background were evaluated using seven treatments concentration of PEG-6000, ranging from 0 to 300 g/L during germination. Significant difference was detected for drought tolerance among seven treatments, and optimum concentration of PEG-6000 was 200 g/L based on the principal components analysis for five indexes related to drought tolerance, including drought resistance index, relative germination rate, relative sprout potential, relative root length and relative shoot length. Subsequently, 203 B. rapa collected worldwide were screened for drought tolerance with 200 g/L PEG-6000. Based on the result of membership function value analysis and cluster analysis, we prioritized all the experimental materials according to the drought stress. Additionally, PI226505 from Iran possessed strong drought tolerance, which laid foundation for further research in drought tolerance improvement in oilseed rape.