Anti-rust Identification of Soybean Germplasm Resources

One of the important diseases of soybean rust caused by jicama stripe rust（Phakopsora pachyrihzi Syd）seriously affected growth of soybean.One of the most cost-effective ways to combat the disease is breeding for disease resistance，and screening of resistance resources is the basis for work of breeding for disease resistance.Inoculum concentrations of soybean rust identification were determined by indoor in vitro leaf infection.Optimum inoculum concentration was 100 sporesμL each piece of soybean leaves，inoculum size was 2 μL.Attack time was five days，and urediospores were released from sorus on the seventh day.Disease resistance of 296 varieties of soybean to soybean rust had been identified with microscopic observation and molecular detection techniques.Preliminary screening results showed that only Daqingren showed resistance.And this variety showed obvious disease symptoms after repeated inoculation identification.Rust fungus on infected leaves could be detected by PCR.According to this variety，results showed resistance after repeated inoculation，and other varieties showed susceptibility.