Estimating Mating Patterns in Forest Tree Populations : Biochemical Markers in the Population Genetics of Forest Trees

The Hague

1991

S. 157-172

zahlr. Lit. Ang.

Bandaufführung

74919

Pollen successful in fertilizing viable offspring in forest trees is derived from three sources: self-fertilization, cross-fertilization with mates within the same local population, and cross-fertilization with mates from outside the local population (gene flow). In this paper, methods of evaluating each of these sources from the segregation of isozyme genetic markers in the offspring of individual mother trees are described and empirical results in conifer species reviewed. Patterns of cross-fertilization in conifers are little understood; yet, cress-fertilization accounts, on average, for around 90% of all offspring. In clonal seed or chards, gene flow may be responsible for up to one-half of cross-fertilized progeny, but the degree to which this is true in natural stands is unknown. A probability model approach for studying mating patterns within local populations, even when they are not isolated from external pollen sources, is introduced, and then applied to offspring data from a Douglas-fir seed orchard. Estimates of the mating parameters derived with this approach were found to be consistent with previous information on cross- fertilization in seed orchards. In particular, for any one mother tree, crosses with near neighbors appear to account for only a small percentage of total offspring.