Canadian Forest Service Publications

Temporal variation in the outcrossing rate in a natural stand of western white pine. 1993. El-Kassaby, Y.; Meagher, M.D.; Davidson, R. Silvae Genetica 42: 131-135.

Year: 1993

Issued by: Pacific Forestry Centre

Catalog ID: 3307

Language: English

Availability: Not available through the CFS (click for more information).

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Population and individual-tree multilocus outcrossing rates were estimated for three successive pollination years (1983 to 1985) in a natural stand of white pine (Pinus monticola) using allozyme variation at 6 loci. Population outcrossing rate estimates were nearly static and did not differ significantly over the three years studied. Individual-tree outcrossing rate estimates were dynamic and varied within and among years. Some consistent "inbreeders" and "outcrossers" were identified, however, the outcrossing rate of most trees varied, indicating that these variations were caused by the pollination biology, phenology, or ecology. Our results parallel those reported in most conifer outcrossing-rate studied and support the hypothesis that outcrossing rate is under genetic control and that the among-tree temporal variation is mainly environmental. The observed fluctuation of individual-tree outcrossing-rate estimates indicates that parental ranking using wind-pollinated seeds requires statistical adjustment on the individual tree within a crop year.