Selection and testing of conifers - Marker aided selection (MAS)

 

Summary

MAS selection works by identifying molecular markers (bands on a gel) which are associated with extremes of variation e.g. very high wood density, very good stem form, very good frost resistance. Once breeders know which bands on the gels indicate extremes for the traits under selection, then screening can be restricted to the laboratory and can be performed for as many traits as there are markers.

Potential

The potential impact of MAS on traditional breeding is huge. If successful, it allows the selection of superior genotypes at a very young age in the laboratory. Since these selections are still very young, they could be clonally replicated using existing technology. Breeders could then do away with expensive field trials and extra gain will get out to the forest managers very soon after mating the selections from the previous generation.

The system does however assume that clonal forestry will be operational and socially acceptable in order to achieve its full potential. Sexual reproduction following MAS of parents is possible but gains will be less and much delayed relative to the clonal route. This is because delays are likely whilst the juvenile selections are brought to flower and the resulting planting stock will not be genetically identical to the parents.

The project

The first step in MAS involves identifying the markers associated with extreme phenotypic traits. Forest Research are currently performing a project,  spread over the next 10 years or so, to identify markers in Sitka spruce.

In spring 2002 we planted four ramets from each of 1,500 genotypes randomly selected from within each of four families over three different sites (Scotland, England, Wales); 24 000 trees per site, 72 000 trees in total. Spacing was the normal 2m x 2m creating a need for nearly 10 hectares per site.

Since this series of experiments constitutes a unique and very large clonal test replicated over three sites, other Project Leader and Institutions are encouraged to participate. If you think you would like to impose a (non-destructive!) experiment on this MAS experiment which will contribute to the genetic mapping of Sitka spruce or armory of markers please discuss your proposal with Steve Lee (steve.lee@forestry.gsi.gov.uk) prior to submitting you experiment plan.