Abstract
To evaluate current genetic diversities and further conservation efforts affecting the brackish water angiosperm, Zostera japonica Aschers. & Graebn., we carried out microsatellite analysis of three populations located in Tottori prefecture. The three populations consisted of one, four or 13 genotypes (genets), and the genotypic and genetic diversities were low compared with previously studied related species such as Z. noltii and Z. marina. Moreover, outcrossing reproduction but not self-reproduction was speculated by multi locus genotypes observed in one population in Lake Nakaumi. Observed heterozygosities were not significantly lower than expected in all populations. These results suggested that seed propagation was limited in the populations studied, and vegetative propagation was primarily involved in maintaining the populations. Moreover, limitations in seed propagation were not only caused by environmental factors, but might also be related to the breeding system or genetic factors such as inbreeding depression.
