Mating System and Genetic Diversity in Holm Oak (Quercus Ilex L. Fagaceae) : Biochemical Markers in the Population Genetics of Forest Trees

The Hague

1991

S. 149-153

18 Lit. Ang.

Bandaufführung

74916

Genetic diversity was studied using 3 polymorphic enzyme loci in 37 natural populations of holm oak. Diversity was high in each population (e.g., average allele number per population at the PGI1 locus was 4.35, range from 2 to 6). moreover, it was shown in each site that: 1. The rate of outcrossing is very high and a genetic self-incompatibility system is likely present; 2. the reproductive period differs substantially among the trees; 3. investment of each individual tree in sexual organs (either male or female) and in vegetative biomass is very variable. These characteristics combine to diversify the sources of effective pollen which fertilizes each acorn-producing tree. This hypothesis is also supported by the study of allele frequencies in the effective pollen responsible for the observed progenies of several open- pollinated individual trees in the site of Puechabon, near Montpellier, France. The greatest part of the genetic diversity observed in this whole site (158 trees) was recovered in each progeny. Consequences of mating system on survival and colonizing ability of this species occurring in the occidental mediterranean Basin are examined.