Genetic structure of Camellia japonica L. in an old-growth evergreen forest, Tsushima, Japan

The spatial genetic structure of Camellia japonica was investigated, using microsatellite markers, in a 4-ha permanent plot within an old-growth fores t. Spatial distribution of individuals was also assessed to obtain an insig ht into spatial relationships between individuals and alleles. Morisita's i ndex of dispersion showed that 518 C. japonica individuals in the plot were clumped, and Moran's I spatial autocorrelation coefficient revealed weak g enetic structure, indicating a low level of allele clustering. Average I co rrelograms showed that there was stronger genetic structure over short-dist ance classes. The clumped distribution of individuals and the positive auto correlation over short-distance classes may result from the limited seed di spersal and microsite heterogeneity of the stand, while the genetic structu re may be weakened by overlapping seed shadow and extensive pollen flow, me diated by animal vectors, and the high outcrossing rate found in C. japonic a.