MARKER-ASSISTED SELECTION IN FOREST TREE BREEDING PROGRAMS AS ILLUSTRATED BY 2 EXAMPLES - MARITIME PINE AND EUCALYPTUS

The arguments raised against the feasibility of marker-assisted select ion (MAS) in forest trees, especially the expected absence of linkage disequilibrium between markers and quantitative trait loci (QTL) in la rge random mating populations, are reconsidered. A decrease in costs a nd automation of the random amplified polymorphic DNAs (RAPD) techniqu e make it possible to construct single-tree maps for every individual of an elite breeding population: an extreme alternative to dealing wit h linkage equilibrium. Mapping strategies and QTL detection using exis ting pedigrees in forestry breeding programs (half-sib and full-sib pr ogenies) are presented and discussed. The feasibility of MAS is illust rated for the maritime pine and eucalyptus breeding program. Genetic g ains and costs associated with the use of molecular markers are evalua ted and compared to other strategies that aim to obtain a similar sele ction efficiency.