Mapping of quantitative trait loci in loblolly pine and Douglas-fir: A summary

Classical quantitative genetic approaches have yielded a depth of understanding of the heritability and partitioning of variance of important traits in forest trees. Such knowledge has been applied in the genetic improvement of many species. Genetic improvement based on phenotypic selection in forest trees is rather slow however due to the long generation time in trees and the time to phenotypic evaluation. Genetic marker based approaches to tree improvement would increase the speed and precision of breeding. For this goal to be realized, the genes controlling quantitative traits must be identified. We summarize our progress toward achieving this goal based on a series of quantitative trait locus mapping experiments in two important conifer species. The path toward discovery of economically important alleles is now clear.