SPATIAL AUTOCORRELATION OF ALLOZYME TRAITS IN A NORWAY SPRUCE (PICEA-ABIES) POPULATION

Using isoenzymes as gene markers and spatial autocorrelation analysis as a tool to detect spatial patterns, we studied the spatial distribut ion of genotypes in a naturally regenerated uneven-aged Norway spruce (Picea abies (L.) Karst.) stand on the eastern Italian Alps. In most c ases we found a random distribution of genotypes in space; in the whol e data set less than 11% of genotype pairs showed positive association s for the first (10 m) distance class. Extensive gene flow, due to lon g distance dispersal of pollen and seeds in P. abies, may account for the observed spatial patterns. A few genotypes (GotB-22, LapB-23, LapB -24, SkdB-12, and MnrB-12) showed a significant clumped distribution o ver a small spatial scale. We suggested that selection processes drive n by environmental variability might have produced significant clumpin g of these genotypes. However, the role of factors linked to the breed ing system, and of chance events, in determining the population spatia l structure cannot be excluded in our study.