Genetic and Phenological Differentiation Between Introduced and Natural Populations of Quercus rubra L : Genetics of Oaks. IUFRO Proceedings

1993

S. 271-280

16 Lit. Ang.

Unselbständiges Werk

200041670

Gene diversity within populations of Quercus rubra was compared between 23 introduced stands and 9 geographic regions within the natural range for 4 enzymes encoded by 4 polymorphic loci. Gene diversity within populations was, in general, higher in introduced stands than in geographic regions, due to differences in allelic frequency profiles. For 2 loci, there were directional increases of frequencies of rare alleles in introduced stands as compared to geographic regions, whereas the mean number of alleles was lower in the former populations. Similarly, intraspecific variation among 15 introduced stands was compared to geographic variation among 18 origins in the natural range for bud flush and leaf coloration in experimental plantations established in France. There was a clinal latitudinal variation for both phenological traits in the natural range. The introduced populations occupied an intermediate position in the rankings for both phenological traits. A hypothesis of genetic differentiation between introduced and natural populations is proposed in light of the results obtained.