Objective: To establish optimal inter-simple sequence repeat-polymerase chain reaction(ISSR-PCR) reaction system for Gentiana straminea and provide a reference for medicinal germplasm identification and genetic diversity research.Method: Influencing factors of ISSR-RCR reaction system(template DNA,Mg2 +,d NTPs,Taq DNA polymerase,primer and annealing temperature) were selected and optimized by single factor tests and orthogonal test.Result: Optimum reaction system(20μL) contained template DNA of 1μL(36mg·L-1...