Most studies of screening waterlogging tolerance were performed at a specific development stage,with the implicit assumption that differences in waterlogging tolerance expressed in these systems will result in improved yield performance in fields.It is necessary to examine these criteria in fields.Three experiments were carried out to screen waterlogging tolerance in 25 rapeseed(Brassica napus L.)varieties at different development stages,including seedling establishment stage and seedling stage at controlled environment,and maturity stage in fields.Yield related traits at maturity stage and morphological traits of seedlings at the other two stages were evaluated.Correlation analysis between waterlogging tolerance coefficient(WTC)of yield and other traits was performed.Variations of WTC of yield were found among different varieties,providing an important basis for further development of breeding more tolerant materials.The assessments for physiological parameters at three growth stages suggest that there were difference of waterlogging tolerance at all the development stages.The results indicated that flash waterlogging restricts plant growth and growth is still restored after removal of the stress.Correlation analysis between WTC of yield and other traits revealed that there was consistency in waterlogging tolerance of the genotypes until maturity,and good tolerance at seedling establishment stage and seedling stage can guarantee tolerance in later stages.The waterlogging-tolerant plants could be selected using some specific traits at any stage,and selections would be more effective at seedling establishment stage.Our study provides a method of screening waterlogging tolerance,which would be a suitable basis for initial selection of a large number of germplasm or breeding populations for waterlogging tolerance and help for verifying their potential utility in crop-improvement.