Identification of race of Phytopthora sojae and screening of soybean cultivar resistance

Eighteen isolates of P.sojae were isolated with V-8PBNIC selective medium from 5 counties or cities in Helongjiang province. Five races were identified based on the response of the isolates in 13 resistant monogenic lines, with 12 isolates identified as race1, 2 isolates as race13 and 4 isolates as 3 new races. Virulence formula of the three new races were 3a, 3b, 3c, 5; 3b and 1a, 1d, 3c, 5,6, respectively. The results of inoculating 55 cultivars from Huanghe and Huaihe Basin showed that 30 cultivars were resistant, 14 cultivars were susceptable and 9 cultivars were intermediate to race 1.