Objective: To analyze genetic diversities of Mucuna pruriens from different habitats according to their DNA molecule and investigate genetic relationships among them. Method: Inter-simple sequence repeat(ISSR) molecular marker technique was adopted to analyze genetic diversity of M. pruriens from different habitats

ISSR-polymerase chain reaction(PCR) amplification procedure was as following:preliminary denaturation at 94 ℃ for 4 min;40 cycles each involved denaturation at 94 ℃ for 45 s

annealed at 48-54 ℃ for 1 min and extended 90 s at 72 ℃;extended at 72 ℃ for 7 min and kept at 10 ℃.Based on single factor tests

effects of five main reaction elements(Mg2+

Taq DNA polymerase

dNTPs

template DNA and primers) on ISSR-PCR were optimized by orthogonal test.Eleven samples was analyzed by Ntsys-pc and Popgene software. Result: Optimum reaction system was as following:template DNA of 20 ng

ISSR primers of 0.3 μmol · L-1

dNTPs of 0.15 mmol · L-1

MgCl2 of 2.4 mmol · L-1

Taq DNA polymerase of 1 U with 5 U · μL-1

PCR buffer of 2 μL

adding sterilized water to 20 μL.Ten ISSR primers with good repeatability and clear loci were selected from 40 primers and used for ISSR amplication

97 loci were amplicated

in which 25 were polymorphic loci

accounting for 25.8%.Genetic similarity coefficient of 11 samples was 0.866 0-0.969 1 and samples could be classified into three groups. Conclusion: Genetic variation of M. pruriens has a close relationship with geographical distribution

but genetic variation is small with strong genetic stability.