Preliminary studies on relationship between mating type and pathogenicity of Phytophthora capsici

Twenty-two isolates of Phytophthora capsici Leonian were obtained from the diseased pepper plants collected in Hefei,Huainan,Hexian,Qianshan and Yuexi by means of tissue isolating method in order to know about the mating type distribution and pathogenicity difference.The test of mating types of the isolates of P.capsici from different areas was carried out by matching pairs with standard isolates,and the pathogenicity was investigated by using two pepper cultivars with leaf in vitro inoculation.The results showed that there existed two mating types of A1 and A2 in the tested isolates of P.capsici.A2 was the predominant and distributed in all sam-pling regions with frequency of 81.8%.There was significant difference in pathogenicity to different pepper culti-vars.The average disease severity of the detached leaves of pepper Yanyang ranged from 1.0 to 4.8 and the the average disease severity of the detached leaves of pepper Hefengtianrui ranged from 1.5 to 4.5.The isolates col-lected from different regions showed different pathogenicity while the pathogenicity of isolates from the same region also showed difference.The pathogenicity of P.capsici was related with pepper cultivars,but there was no significant correlation between mating type and pathogenicity of the isolates P.capsici.