• amplified fragment length polymorphism;
  • genetic similarity;
  • genetic structure;
  • spatial distance;
  • Quercus

The spatial genetic structure was assessed by amplified fragment length polymorphism (AFLP) technique for Quercus crispula Blume (37 individuals) and Q. dentata Thunberg (54 individuals) growing along a 550-m transect in Ishikari, Hokkaido, northern Japan. The simple Mantel test revealed significant negative correlation between genetic similarity and geographic distance in Q. dentata and negative but insignificant correlation in Q. crispula. Spatial autocorrelation analysis revealed that Mantel's r generally decreased from positive to negative values with the increase of spatial distance in both oak species with significant deviation from zero for the 50–100-m (positive) and 250–300-m classes (negative) in Q. dentata. Thus, significant spatial genetic structure was revealed at least in Q. dentata