Abstract:Clubroot is爋ne爋f爐he爉ajor diseases爋f燾ruciferae爒egetable燾rops,燼nd燾auses爂reat爀conomic爈oss.?Broccoli爄s an important燾ruciferae爒egetable,爓hich爃as燼 good anti-cancer effects. In recent years, the occurrence of clubroot is growing in the main producing areas of broccoli, such as Zhejiang, Yunnan province. Cultivating resistant varieties based on identification and screening clubroot-resistance accessions is the most cost-effective method of preventing the disease. To爀xplore燼vailable爎esistant germplasm aganinst NO.4 race, the mainstream Plasmodiophora brassicaerace race in china, 525燽roccoli燼ccessions and their relatives were artificial爄noculated using irrigating injured root method. The爎esults爏uggested爐hat?燼ccessions?爄nbred爈ines) were middle resistant (MR),燼ccounting爁or?.12%?189 accessions爓ere susceptible牋(S), accounting爁or?2.38%;252燼ccessions爓ere爃ighly susceptible (HS),燼ccounting爁or?6.50%;no accessions were highly爎esistant?HR)爋r爎esistant?R)燼mong 446 broccoli accessions (including 393 inbred爈ines,?3爃ybrids). Among 85 relatives?including? cabbage accessions,?2 cauliflower,7 Chinese燾abbage?? turnip, 12 chinese kale,? kohlrabi,8 flowering chinese cabbage,2 oilseed rape,2 wild accessions,1 Barbarea vulgaris),爐here were 1 immune(I) accession 1爃ighly 爎esistance?HR)燼ccession,?爎esistant?R)燼ccessions,?爉iddle爎esistance?MR)accessions,?9 susceptible?S)燼ccessions and 37爃ighly susceptible?HS)燼ccessions.營n short,there were more resistant type lines(HR,R,and MR) in relatives than that in broccoli lines. These materials would provide clubroot-resistance source for breeding in燘rassica爋leraece.