Abstract: 【Aim】To analyze the genetic differentiation of rDNA-ITS1 sequences among the geographical populations of Liriomyza sativae Blanchard and to provide molecular markers for identifying L. sativae against its closely related species. 【Method】 rDNA-ITS1 regions of eight geographical populations of L. sativae from China were sequenced by using PCR product sequencing method or clone sequencing method, and rDNA-ITS1 sequences of three closely related species (L. trifolii, L. huidobrensis, and L. bryoniae) were retrieved from GenBank. The rDNA-ITS1 sequences among populations of L. sativae and their closely related species were analyzed using MEGA3.1. 【Results】 The ITS1 difference among the geographical populations of L. sativae was very low, with only 8 variable sites for L.sativae and genetic distance below 0.02. But the difference of the ITS1 sequences among L. sativae and its closely related species was significant, with 126 variable sites, 12 authenticable sites for L.sativae and genetic distance between 0.149－0.390 【Conclusion】 Despite of the low diversity, the trends of differentiation of geographical populations of L. sativae were consistent with the geographical distribution. The characteristics of rDNA-ITS sequence can be used as good markers for authenticating L. sativae populations form their closely related species.  

Key words: Liriomyza sativae, geographical populations, closely related species, rDNA-ITS1, genetic differentiation