multi-locus enzyme systems were studied in a black spruce {picea maniana (mill.) b.s.p.) clonal seed orchard in northwestern ontario. the embryonic and megagametophytic tissues of each clone were sampled and electrophoretically analysed to examine the inheritance pattern of 8 polymorphic loci. with the exception of leucine aminopeptidase (lap) and aconitase (aco), allozyme segregation followed expected 1:1 ratios. the mating system is characterized by a moderate level of selfing (s=0.15) and a small effective population size. the ratio of genetically effective males to receptive females was calculated to be 0.31. although the parental population was in hardy-weinberg equilibrium, the majority of the enzyme systems examined revealed a deviation from the hardy-weinberg equilibrium in the filial generation. several loci exhibited heterogeneous pollen pools and there was an observed excess of heterozygotes. indications of non-random mating and small effective population size invalidate two basic seed orchard assumptions, namely, random mating and large population size.