genetic map of Welschriesling x Sirius for the identification of magnesium-deficiency by QTL analysis

A genetic linkage map of grapevine was constructed with 92 progeny, which was derived from a cross of Welschriesling x Sirius using the pseudo-testcross strategy. Welschriesling is known for showing low magnesium uptake. The segregation pattern of this defect was compared with the segregation pattern of 251 molecular markers, 237 simple sequence repeat (SSR) and 14 random amplified polymorphic DNA (RAPD) marker. These markers were used to construct the parental genetic maps and could be arranged into 20 linkage groups. The maternal (Welschriesling) and the paternal (Sirius) maps were aligned in one consensus map. Mapmaker 3.0 software was used for the calculations of linkage groups. The genetic map rendered it possible to identify a QTL (quantitative trait loci) in linkage group 11. This loci can be associated with visual symptoms of Mg lack and the amount of Mg concentration in the leaves of the grape zone. The SSR markers VVS2 and VMC 6g1 showed the highest linkage to the core region of the Mg-QTL.