The mating system in a black spruce clonal seed orchard

Abstract

Isozyme markers were used to study the mating system, estimate the effective population size, and determine the effective gene pool composition in a black spruce clonal seed orchard. Ten seeds per family were electrophoretically analyzed by embryo and megagametophytic pairs to determine their allelic and genotypic frequencies at five polymorphic loci. Single-locus estimates of outcrossing ranged from 0.682 to 1.087 (mean, 0.942), while the multilocus estimate was 0.837. The variance effective population size was calculated to be 17 individuals, comprising 13 receptive females and 4 effective males. Evidence of gene pool heterogeneity suggested a small, nonrandomly mating population within the clonal seed orchard.