GENETIC-STRUCTURE WITHIN A JAPANESE STONE PINE (PINUS-PUMILA REGEL) POPULATION ON MT. AINO-DAKE IN CENTRAL HONSHU, JAPAN

In previous investigations, natural layering of Japanese stone pine (P inus pumila) was suggested by the occurrence of adventitious roots. Ho wever, there is no genetic evidence so far that this species actually produces offspring by natural layering. We, therefore, investigated cl onal structure and spatial genetic structure within a 38X18 m plot on Mt Aino-dake, using allozyme, random amplified polymorphic DNA (RAPD), and inter-simple sequence repeat (ISSR) analyses. We found 24 genets, with stems found to be genetically identical in multiple tests, which extended laterally against the direction of the slope, indicating tha t there were clonal structures originating from elongation of ramified stems and subsequent natural layering. The results suggest, however, that less than one third of the 200 stems analyzed from this site were clonaly propagated. We also analyzed spatial genetic structure by spa tial autocorrelation, Many of the spatial autocorrelation coefficients were significantly positive in short distance classes. We concluded t hat the species has genetic structures which largely originate from cl onal propagation and avian seed dispersal.