Canadian Forest Service Publications

Genetic diversity and population structure of disjunct Newfoundland and central Ontario populations of eastern white pine (Pinus strobus) 1998. Rajora, O.P.; DeVerno, L.L.; Mosseler, A.; Innes, D.J. Canadian Journal of Botany 76: 500-508.

Year: 1998

Available from: Atlantic Forestry Centre

Catalog ID: 6149

Language: English

CFS Availability: Order paper copy (free)

Abstract

The dramatic decline of eastern white pine (Pinus strobus L.) populations in Newfoundland over the past 100 years presents an opportunity to determine and monitor population bottleneck effects on genetic diversity in trees. To provide benchmarks and indicators for monitoring genetic changes due to recent and future bottleneck events and to assist development of conservatin strategies, we assessed genetic diversity and structure of six small, isolated white pine populations from two regions at the limits of its geographical range in Newfoundland for comparison with three populations from its central range in Ontario for 20 allozyme loci coding for 12 enzymes. On average, 47.8% of the loci were polymorphic, the number of alleles per locus was 1.75, and the observed and expected heterozygosities were 0.215 and 0.195, respectively. Although most of the alleles were widespread, unique alleles were found in three of the nine populatins examined. The Newfoundland populations were as genetically variable as those from Ontario. Generally, all populatins exhibited slight excess of heterozygotes at most loci. Only 6.1% of the detected genetic variation was among populations, and the remainder among individuals within populations. The genetic distances among the populations within a province or region were as great as those among populations between the provinces or regions. Canonical discriminant functions and cluster analysis from genetic distances separated nine populations into the same four groups. Neither provincial nor regional or geographic gradient-related patterns of population variation and differentiation were apparent. It appears that 8000 years of postglacial geographic isolation and recent population delcine have had little or no detectable effect on genetic diversity or differentiation of disjunct Newfoundland white pine populations fromt heir ancestral mainland populations. Assuming their adaptability, the Ontraio seed sources may be acceptable for white pine restoration in Newfoundland.

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