Genetic variation in eleven populations of Picea abies as determined by isozyme analysis

Eleven populations of Picea abies in Sweden were analysed for isozyme variation in four polymorphic loci. Genetic differentiation between geographically isolated populations could be demonstrated, the major part of genic differences occurring in the esterase-A and acid phosphatase-A loci. When populations originating from foreign seeds are involved in comparisons with indigenous populations, higher values of genetic differentiation are found. Genic variability within populations was estimated from “average heterozygosity”, a measure which is based upon the observed gene frequencies. An increase in “average heterozygosity” was found in two populations of foreign origin, which to a certain extent may be due to intercrossing between genomes of different origin.