Biodiv Sci ›› 2008, Vol. 16 ›› Issue (3): 263-270.  DOI: 10.3724/SP.J.1003.2008.07362

• Original article • Previous Articles     Next Articles

Genetic structure and diversity of Medicago lupulina populations in northern and central China based on EST-SSRs markers

Juan Yan1,2, Haijia Chu1,2, Hengchang Wang1, Jianqiang Li1,*()   

  1. 1 Wuhan Botanical Garden, Chinese Academy of Sciences,Wuhan 430074
    2 Graduate University of the Chinese Academy of Sciences, Beijing 100049
  • Received:2007-12-03 Accepted:2008-02-15 Online:2008-05-20 Published:2008-05-20
  • Contact: Jianqiang Li
  • About author:First author contact:**Contributed equally to this work

Abstract:

Abstract: Medicago lupulina is an annual or short-perennial and widespread herbaceous plant. It is generally considered a selfing species with a strong self-compatibility system, but a shift in mating system towards outcrossing or mix-mating has been reported. To estimate genetic variation, gene flow, mating system and genetic background of M. lupulina, we characterized 354 individuals from 17 wild populations from northern and central China using nine EST-SSRs markers. We found that: (1) EST-SSRs markers had a high percentage of polymorphic loci (PPL = 71.9%) and 4-11 alleles per loci. The Xinjiang-Nalati population had the highest level of genetic diversity (HE= 0.388), whereas the Shaanxi-Xi’an population had the lowest (HE= 0.042). Selfing rate was 93.8 %. (2) Genetic differentiation was high among populations (FST= 0.528; RST= 0.499). Of the total genetic variation, 59.02% was found among populations. (3) Mantel test revealed that genetic distance and geographic distance were positively correlated (r = 0.4141, P≤ 0.0003). Neighbor- joining trees based on Nei’s genetic distance (Da) showed that neighboring populations clustered into the same clade, which was consistent with results of Mantel test. Our results indicated that the genetic structure of M. lupulina populations have been strongly affected by dispersal patterns and a strategy of inbreeding.

Key words: Medicago lupulina, EST-SSR, genetic diversity, genetic structure, selfing