| Pathogen collections of Sporisorium reilianum from Jilin, Changchun, Siping, Songyuan, Gongzhuling Baicheng, Tonghua, Changling et al. were firstly studied by using identification on differential hosts and RAPD analysis in this paper.Through a great number of field investigations and inoculation identifications, six corn varieties( Denghail, Jidan209, Dan639, Nongda3138, Benyu9) and two corn inbred-lines( Mo 17 and Huangzao4 ) widely popularized and used in Jilin province corn production and corn breeding now were defined as ideal differential hosts for pathogens of Sporisorium reilianum .They represented different resistant and susceptible level of corn to Sporisorium reilianum and were able to group the pathogen collections of Sporisorium reilianum from different corn-grown areas in Jilin.Nine pathogen collections of Sporisorium reilianum were inoculated on 8 differential hosts in field. The results showed that 9 pathogen collections of Sporisorium reilianum were divided into 3 pathogenic types in which there were type A with high pathogenicity, type B with moderate pathogenicity and C with weak pathogenicity. Type A were originated in most important corn-grown areas including Changchun ,Jilin,Gongzuling and Changling where corn head smut usually occurs severely, type B were collected from Siping,Tonghua ,Songyuan,Yanbian, and type C were collected from Baicheng where corn head smut usually occurs very lightly.The results of the study on physiological differentiation showed that the results of identification on differential hosts were significantly correlated with their DNA genetic polymorphism, especially in the pathogenic collections with high virulence, this further revealed physiological differentiation of Sporisorium reilianum are due to the differentiation of their DNA.Identification on differential hosts combined with RAPD analysis to research the physiological differentiation of Sporisorium reilianum for the first time in China laid a foundation for the deeper study on that.
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