Association among geographic, allozyme, and growth variables for sugar pine (Pinus lambertiana Dougl.) in southwest Oregon and throughout the species' range

Canonical correlation analyses were used to select sets of allozyme loci that were associated with geographic variables versus sets of allozyme loci associated with growth variables in sugar pine, (Pinus lambertiana). Groupings of populations based on allozymes that were associated with geographic variables indicated that sugar pine populations have diverged into three large, but distinct islands. In contrast, groupings based on allozymes associated with growth variables indicated strong clusterings that are not correlated with geographic variables. Phylogenetic analysis of populations based on allozyme loci that were associated with geographic variables support the cluster analysis and suggest a strong divergence of southern California and Baja populations from Sierra-Nevada populations and a weaker divergence between sugar pine populations in southwest Oregon and the Klamath mountains from the Sierra-Nevada populations. Phylogenetic analysis of populations also support different clusters and suggest that growth responds to an important, but unknown, selective gradient. In spite of these associations, application of neutrality tests such as the Lewontin-Krakauer and Ewens-Watterson tests to all of the allozyme data indicated that the two sets of loci, while different in pattern of divergence, were similar in degree of population differentiation. Implications to sampling for conservation and breeding for growth performance are provided.