Comparison Of Vegetative Compatibility Diversity Of Cryphonectria Parasitica From Wild And Cultivated Chestnut And Molecular Detection Of Mating-type Of The Pathogens From Wild Chestnut

The incidence of chestnut(Castanea.(Tourn.) L.) blight caused by Cryphonectria parasitica in regions of Beijing, Hubei and Shaanxi was investigated and the pathogen strains collected from these regions were used to detect their vegetative compatibility groups(VCGs). The results show that the incidence of chestnut blight in Beijing and Shaanxi, varying according to different site conditions, was higher than that in Hubei. The investigation also showed that, among the three kinds of wild Castanea plant, the chestnut blight incidence of Castanea.henryi is the highest and that of C. mollissima. and C.seguinii Dode. is the second and the third, respectively. The Shannon-Wiener’s diversity indexes of the VCGs of strains collected from Hubei and Shaanxi were statistically higher than that of strains from Beijing, whereas no statistical difference between the indexes of Shaanxi and Hubei. In addition, the mating-types of the representative strains selected randomly from Shaanxi and Hubei population were detected, by means of primary and nested PCR with specific primers. The results showed that both populations had two mating-types, MAT-1and MAT-2. Meanwhile, the strains with two mating-types in a single strain were detected as well, showing higher proportion in Shaanxi population than Hubei population. In the last part of the experiment, In vitro inoculation was carried out with several strains mentioned above, compared with strain EP155, which is of high virulence from North Amerca. We found that most of the strains are of high virulence, and few of them are of middle or low virulence.