Spatial genetic structure of clonal and sexual reproduction in a population of Abeliophyllum distichum (Oleaceae), an endangered monotypic genus

We used allozyme loci, join-count statistics, and Moran's spatial autocorre lation statistics to quantify the spatial genetic structure caused by clona l reproduction from that maintained in sexually reproduced individuals in a population of distylous shrub Abeliophyllum distichum, a monotypic genus e ndemic to the central Korea. The population harbors high levels of multiloc us genotypic diversity (mean D-G = 0.960). Join-count statistics showed tha t there were statistically significant clustering of clonal genotypes withi n distances < 6 m. Both the entire population and the set of sexually repro duced individuals exhibited significant spatial autocorrelation up to the s cale of about < 10 m, and the sexually reproduced individuals are in a subs tantially structured, isolation by distance, manner. This indicated that ge ne flow would not be extensive in a population of A, distichum because of p ine forest acting as a shield for wind movement. Probable unequal ratio of the two floral morphos, selfing via matings between clones, and/or consangu ineous matings may be factors for decreasing seed sets observed in the popu lations of the species ("inbreeding depression"). It is recommended that the sampling for conservation purposes might be perf ormed at a diameter of more than 13 m to extract the genetic diversity acro ss an entire population.