Genetic Diversity Of The Wheat Powdery Mildew Populations In Henan And Hubei Provinces

The genetic diversity of physiologic races and virulence in wheat powdery mildew are used to distinguish the wheat powdery mildew's variations, and the range and quantity are the proof of long-term forecasting and controlling wheat powdery mildew, especially the important basis of disease-resistant cultivar used. It is difficulty in appraising pathogens of large groups of wheat powdery mildew by using the routine method, and uncertainty exists in distinguishing the source of different strain. It is also lack of foresight that development of important physiologic race was evaluated by using routine method. Along with the development of molecular biology, all kinds of molecular markers were widely used to detect the genetic diversity of the populations of wheat powdery mildew. This paper researched the relations of the genetic structure, origin and evolution and of strains of wheat powdery mildew from Henan and Hubei Provinces by ISSR and AFLP.1. Inter-simple sequence repeat (ISSR) marker was used to analyze the genetic diversity of 105 isolates of wheat powdery mildew (Blumeria graminis f.sp. tritici) populations in Henan and Hubei Provinces. The result shows that wheat powdery mildew has rich genetic diversity, The 105 isolates except the No.70 strains were clustered into two groups at the genetic similarity coefficient for 0.801, The first group has 37 isolates, and 35 isolates originated from Henan Province, the second-largest group was made up Henan and Hubei Provinces; At the genetic similarity coefficient for 0.832, the second-largest group can be divided into five groups, The subgroupâ… w as made up 25 isolates in Hubei, The subgroupâ…¡was made up by 12 isolates from Henan, The subgroupâ…¢has 17 isolates in Hubei, The subgroupâ…£has 7 isolates in Henan, The subgroupâ…¤was made up 6 isolates from Hubei. Because each subgroup has only a single Province strains and has not exchange phenomenon in Hennan and Hubei Provinces. There is some bits of communication at the first group. The ruselst showed that there is little communication of wheat powdery mildew from Henan and Hubei Provinces. And the isolates'evolution is relatively independent.2. Amplified fragment length polymorphism (AFLP) and inter-simple sequence repeat (ISSR) markers were used to analyze the genetic diversity of 35 isolates of wheat powdery mildew populations in the west of Henan Province. The results showed it is feasible that AFLP and ISSR were used to the study the genetic of wheat powdery mildew. The genetic diversity level of wheat powdery mildew populations in Henan Province was high(the Shannon's Information index was 0.2815 by ISSR, the Shannon's Information index was 0.5100 by AFLP). AFLP analysis shows genetic diversity was richer than ISSR analysis. And AFLP has the potential to distinguish the genetic diversity.3. Through the contrast based on the genetic diversity of ISSR and virulence of 66 isolates in Henan and Hubei Provinces, showing that they were both relationship with the geography source. Therefore there are certain relationship between the genetic diversity of ISSR and the virulence.