Linkage map of birch, Betula pendula Roth, based on microsatellites and amplified fragment length polymorphisms

The first genetic linkage map for silver birch, Betula pendula Roth, was constructed by using a pseudo-testcross mapping strategy and integration of linkage data from 3 unrelated 2-generation pedigrees. The map is based on the genetic inheritance and segregation of 82 amplified fragment length polyhmorphisms and 19 microsatellite markers, and was constructed by simultaneously comparing the performance of CRI-MAP and OUTMAP packages. The analysis revealed 16 linkage groups, and the total map coverage is 1561 cM (Kosambi units). Average map distance between adjacent markers is 15.5 cM. Linkage groups range between 6 and 18 loci and from 81.2 to 326.5 cM; the remaining 9 linkage groups consist of 2 or 3 loci ranging from 6.3 to 42.4 cM. The uncertainty of the map is illustrated with sensitivity analysis. This initial map can serve as a basis for developing a more detailed genetic map.