Towards construction of an ultra high density linkage map for Pinus pinaster

Two parental linkage maps have been constructed from the P. pinaster reference population (0024 x C803) based on AFLP, SSR and EST markers. Although segregating polymorphism was low due to a high degree of homozygosity in the parents, 12 linkage groups with 26 to 46 markers each were obtained for each parent. The availibility of 70 anchor points based on fragments common to both parents and based on codominant SSR and EST markers allowed to determine homologous chromosomes for both maps and to construct one integrated map. Total genome length of the integrated map is around 2000 cM including 1182 markers. Since some of the EST and SSR markers are also mapped in different pine species, association of linkage groups of our reference population with those of other published maps was possible.