Genetic diversity and clonal structure of Phragmites australis in the Yellow River delta of China

Genetic diversity and structure of 15 populations of Phraginites australis growing in the Yellow River Delta and wetlands nearby were investigated using starch gel electrophoresis. Analysis based on 17 enzyme loci coding for 8 enzyme systems showed that there exists a high level of genetic variability in P. australis. The proportion of polymorphic loci is 49.0%, the average number of alleles per locus is 1.53, and the average expected heterozygosity is 0.221. The genetic diversity was found within populations rather than among populations (G(SI)=0.226). A high level of clonal diversity was indicated in this species with PD (proportion distinguishable variations, PD=0.53). The size of different clones, however, varied significantly. The clonal structure analysis demonstrated a clear genetic mosaic. There is a negative correlation between salinity and growth rate of the reeds. Genetic distances were positively correlated to the geographical distances among populations of P. australis. The populations in saline habitats have become differentiated from their freshwater counterparts. (C) 2003 Elsevier Science Ltd. All rights reserved.