Genetic Diversity and Structure of Euryale ferox Salisb. (Nymphaeaceae) in Japan

We analyzed the population genetic structure of Euryale ferox Salisb. (Nymphaeaceae), an annual aquatic herb, to obtain information useful for conservation of this species. A total of 391 plants from 58 populations throughout Japan and four plants from a population in China were sampled and genotyped using eight microsatellite markers. Within- and among-population genetic diversity of E. ferox in Japan was basically low, with all eight microsatellite loci fixed to single alleles in many populations. However, multilocus genotypes including heterozygous loci were detected from three populations; these populations had inbreeding coefficients (F-IS) not equal to 1.0 and it is assumed that these multilocus genotypes are produced by outbreeding of genetically different individuals. Principal coordinate analysis (PCO) and population genetic structure analysis using INSTRUCT software uncovered at least two genetically distinct groups within Japanese E. ferox populations, neither of which had a simple geographical distribution pattern. This complex genetic structure may be the result of a random fixation of MLGs through genetic drift after habitat loss and by spatial and temporal admixture among populations through seed dispersal and seed banks.