Genetic evaluation of the Swedish spruce breeding population

Background

The Swedish tree breeding has selected more than thousand founder trees of Scots pine and Norway spruce. All future breeding, and most of the Swedish forest in the far future, will be based on offspring from these founder trees. These trees are also used in modern seed orchards. Knowledge about the genetic structure, gene diversity and coancestry of this first funding breeding population allows for more effective use of resources in tree improvement programs as well as better documentation and more reliable prediction of the consequences of tree improvement (e.g. for gene diversity). DNA marker-based analyses will provide a mean to infer the relationship structure among individuals and stands and to predict the relatedness (and thus inbreeding) in future seed orchards. The aim of the project is tto obtain an overview of the genetic structure and relatedness of the founding spruce breeding population for northern Sweden.

Concluding remark

In conclusion, this project is the very first effort to examine the genetic property of the Swedish spruce breeding stock. Our evaluation of the founders for northern Swedish spruce breeding revealed high genetic diversity and low relatedness in the whole collection as well as within each breeding zone. The nine breeding populations of Norway spruce constitute a good sample of natural variation of that species in northern Sweden. The little structure (also fine scale) in genetic variation in this material implies that the selections cover most of the existing variation and wider sampling for the breeding program is not needed.

It is assuring for future breeding program that high genetic variation is in stock since the higher the variation the more progress can be expected from the resulting forests that combine with desirable variations. Low coancestry is also good information, as it means that production forest can be generated with little suffering from inbreeding depression; and that the gene mass in founders to the breeding stock is high and unrelated. Moreover, high genetic diversity in the breeding populations comprises valuable resources for conservation which must take into consideration not only timber, but also the forest ecosystem including the ecological and social benefits.