Northern corn leaf blight or Turcicum leaf blight is the most serious disease in the maize growing areas all over the world. The occurrence and epidemics of this disease are affected by the composition and variation of Exserohilum turcicum population. This paper focuses on identifing in pathogenic variation to different Ht resistance gene and the population structure of the pathogen based on AFLP. The results are of significane to the resistant-breeding as well as to control variation of physiolo...