Identification of Races of Plasmodiophora brassicae from Four Different Regions and Resistance Identification of New Cabbage Cross Combinations

Williams identification system was used to identify the races of clubroot (Plasmodiophora bras‐sicae) in four different regions (Fuling District of Chongqing ,Xindu District of Chengdu in Sichuan ,Song‐ming County of Kunming in Yunnan and Yanbian County of Panzhihua in Sichuan) .The races were identi‐fied to be NO.4 ,NO. 11 ,NO. 7 and NO. 7 ,respectively .Then natural identification method in the field was applied and race No.4 ,which was the dominant race of clubroot in Fuling ,was used to test the resist‐ance of 79 cabbage cross combinations .Eight combinations were shown to be highly resistant to the dis‐ease ,20 were resistant ,20 were tolerant and 31 were susceptible .In addition ,8 excellent cross combina‐tions with good economic traits and resistance were inoculated with race No.4 in the laboratory .The result showed that GZ04 ,GZ09 ,GZ40 ,GZ76 and GZ80 were tolerant ,GZ03 and GZ19 were resistant ,and GZ78 was highly resistant to clubroot .