MATING SYSTEM IN NATURAL-POPULATIONS OF EASTERN WHITE-PINE IN QUEBEC

The mating system in two natural eastern white pine (Pinus strobus L.) populations in Quebec was investigated. These populations contrasted in density and age. The single-locus as well as multilocus outcrossing rate estimates were obtained from four polymorphic enzyme loci using open-pollinated progeny data. The single-locus outcrossing rates range d from 0.934 to 1.110 with a mean of 1.026 in one population and varie d from 0.862 to 1.186 with a mean of 1.007 in the other population. Mu ltilocus estimates exceeded 1.0 in both populations, suggesting the po ssible absence of self-fertilization. Pollen pool gene frequencies wer e homogeneous in one population and heterogeneous in the other. The po sitive or less negative F-values found in the filial populations compa red with those observed in the parental populations suggest the presen ce of a family structure favouring consanguineous matings.