Genetic diversity of Spartina alterniflora in coastal areas of China

Mitocondiral nad1 gene and chloroplast fragment trnT-trnL of Spartina alterniflora were amplified and sequenced for 20 samples collected from the Middle, Northern and Southern populations with phenotypic variations in coastal areas of China and the population genetic diversity were determined. Based on 3 polymorphic sites from the sequencing fragment, 20 samples of S.alterniflora were divided into 4 haplotypes. The Haplotype diversity and Indel Haplotypes diversity was 0.189 and 0.542, respectively. The mean of Nei’s genetic distance among populations was 0.028. Coefficient of gene differentiation between populations (Gst) between Southern population and Northern population or Middle population was 0.015 2 or 0.004 15 and both of the fixation index(Fst)was 0. Genetic diversity completely came from within-population variations. The results indicated that S.alterniflora in China had very low genetic diversity and no genetic differentiation between these three populations. Phenotypic plasticity might explain more phenotypic variation of S.alterniflora along the coastal line of China. Moreover, S.alterniflora in Chong Ming Island showed different genetic features from other populations.