Objective  To reliably identify strains of Grifola frondosa and precisely determine the genetic relationship among them.

  Method  The identification and genetic diversity analysis on 11 strains of G. frondosa were carried out by the combined use of the antagonistic challenging test and ISSR.

  Result  The antagonistic test on the strains demonstrated apparent differences on their responses. Presence or absence of antagonism allowed the classification of the strains into 4 distinct groups. Meanwhile, from the ISSR analysis, when the similarity coefficient reached 0.87, the strains were clustered into 5 groups. They were Group 1 that included Strain #1 (Shijiazhuang ash tree flower), Strain #2 (stage ash), Strain #10 (XG-W), Strain #5 (Gr0001+2), Strain #6 (CN), and Strain #7 (snow circle); Group 2, Strain #11 (CN-9); Group 3, Strain #4 (Gr0003); Group 4, Strain #8 (H) and Strain #9 (Hokto); and, Group 5, Strain #3 (Gr20).

  Conclusion  It appeared that Strain #1 and Strain #2 belonged to a same species; so were Strains #5, Strain #6 and Strain #7, and Strains #8 and Strain #9. At the similarity coefficient of 0.8, Strain #4 could be clustered with Strain #8 and Strain #9 with slight differences indicating a distance on genetic relationship among them. Strain #3 had a lowest coefficient of 0.34, therefore, it was most remotely related to all.