Population Structure Of Alternaria Solani From Potato In Hebei Province And Resistance Evaluation Of Potato Cultivars Against To Early Blight

Potato is the fourth food crop in the world, which is behind rice, wheat and corn."International Year of the Potato (IYP)"was declared by the United Nations in 2008. And it has high-lighted the important position of potato in the global food system. The potato early blight was one of the most important diseases in potato production. In this research, all of five aspects were study on the pathogen and host.1. The population genetic structure of 145 isolates of Alternaria solani collected from potato in Hebei province and 30 ones in other four provinces in China from 2009 to 2010 was revealed against phenotypes such as virulence of Mancozeb. Mancozeb showed good inhibitory effect for all tested strains, the range of EC₅₀ values was between 1.04 and 4.86μg/mL, and their average was 2.93μg/mL.2. Sporulation quantity of the tested 47 isolates in Weichang and Zhangbei county of Hebei province and 30 ones in six counties of other four provinces in China were examined. The results showed average sporulation quantity in two counties of Hebei provinces were higher than those in six counties of other provinces.3. The genomic DNA of 175 isolates was amplified with 3 selective primer combinations. A total of 231 AFLP bands were obtained, covering 100%, showed polymorphism. The population genetic analysis indicated that the genetic diversity level of Alternaria solani population was high.4. AFLP genotypes revealed a high diversity of Alternaria solani collected from potato and every isolate had a specific AFLP genotype. AFLP genotype of isolates was closely related to their geographic origin, some collective with sprolation quantity, however, not correlative with sensitivity of mancozeb to pathogen.5. A total of 16 potato cultivars were tested for identification and evaluation of resistance to Alternaria solani by the detached leaflets inoculation with Indole Acetic Acid (IAA) treatment. The results showed that all tested 16 varieties were susceptible, however, three varieties i.e. Kexin4, Kexin12 and Kexin13 were light susceptible to Alternaria solani.