GENETIC-VARIATION IN LOW ELEVATION DOUGLAS-FIR OF BRITISH-COLUMBIA AND ITS RELEVANCE TO GENE CONSERVATION

Patterns of variation were studied at 20 isozyme loci in 49 coastal, l ow-elevation Douglas-fir populations in SW British Columbia and NW Was hington State. Several components of variation were estimated for each population including the number of alleles per locus N-a, number of a lleles N-a(95], inbreeding B heterozygosity H, and population divergen ce D. F was near zero indicating nearly complete outcrossing within po pulations. H was quite high (16%) and in accord with previous studies of Douglas-fir. D values were low (equivalent to Wrights F-ST of 0.08) indicating levels of gene flow sufficient to largely homogenize popul ations. The parameters of diversity N-a, N-a(95), H, and D showed litt le intercorrelation across populations. A homogenous pattern of geneti c relationship among populations was shown by the clustering of popula tions based on their inferred relationship, and by the principal compo nents of the matrix of inferred genetic relationship. Because of the c omplex nature of gene diversity and the continuous nature of populatio n differentiation in Douglas-fir, it is difficult with isozyme markers to identify specific populations of value for genetic conservation in this species.