Analysis Of Genetic Diversity Of Phytophthora Sojae Based On SSR,ISSR And RAPD Makers

Soybean Phytophthora root rot(PRR) caused by Phytophthora sojae is a devastating diseases of soybean.PRR causes serious losses in soybean production areas.Because of the rapid pathogenic variability of Phytophthora sojae,control this diseases through breeding and make good use of resistant cultivaters has become difficult Five main aspects of this study as followed:1. The virulence types of 30 P. sojae isolates from 6 different areas were identified,the results were compared with the virulence types of reported races,the virulence type of thses 30 isolates are all new types.there is no obvious correlation between the origion of the isolates and the virulence type.Isolates from different areas and different isolates from the same area show great virulence difference.Main virulence types varies in different areas. Virulence composition of P. sojae population is complex.2.18 SSR markers were used to assess the genetic diversity of 30 P. sojae isolates.85 alleles were detected in 30 P. sojae isolates by 18 SSR primers, with an average of 4.27. The order of Shannon's Information index of different areas is:Heilongjiang> Anhui> Xinjiang> Henan> Fujian> America. The populations from Anhui and Heilongjiang are closer than others, and the population from America and Fujian are moer distant than others.The 30 isolates can be efficiently distinguished by primer PSG113,PSG133,PSG125. The data were analyzed by NTSYS-PC 2.1 software and the result is quite similar to virulence analyze.3.13 SSR markers were used to assess the genetic diversity of 30 P. sojae isolates.79 alleles were detected in 30 P. sojae isolates by 18 SSR primers, with an average of 6.08. The order of Shannon's Information index of different areas is: Henan>Heilongjian>Xinjiang>Fujian>Anhui>America. The populations from Xinjian and Heilongjiang are closer than others, and the population from America and Fujian are moer distant than others.Population from America show less similarity to other groups.4.21 RAPD markers were used to assess the genetic diversity of 30 P. sojae isolates.78 alleles were detected in 30 P. sojae isolates by 21 RAPD primers, with an average of 3.71. Populations from 6 areas show high levels of polymorphism.The order of Shannon's Information index of different areas is:Heilongjiang>Henan>Xinjiang>Anhui>Fujian>America.The populations from Xinjian and Henan are closer than others, and the population from America and Fujian,America and Xinjian are moer distant than others.Population from America show less similarity to other groups. The genetic diversity levels of populations from Beijing and Shandong were higher than those of other regions.5. The genetic similarity coefficient obtained by 3 approaches was analyzed,two dominate makers system(ISSR and RAPD)show the best correspondence(0.543);There is weak correspondence between SSR and RAPD(0.393);Maker system (SSR and ISSR)show no correspondence(0.243).The genetic diversity levels obtained by 3 approches differs,may be different maker system revals different genetic site,and the use of different maker is the reason.