Integration of Microsatellite- and Functional Gene-Based Markers for the Improvement of a Grapevine Genetic Map

A mapping population derived from the cross between the grapevine (Vitis vinifera) cultivars ‘Regent’ and ‘Lemberger’ was used for the construction of a genetic map and the detection of putative QTLs involved in resistance to Uncinula necator and Plasmopara viticola. ‘Regent’ shows high field resistance against both diseases. Different types of molecular markers were used to genotype 144 F1 descendants of the cross. The genotypic information obtained with this set of markers was analyzed by JoinMap 3.0 software for the construction of the genetic map. The map information was combined with phenotypic evaluations of five years for QTL analysis using MapQTL 4.0 software. Four hundred and thirty markers could be mapped employing the Kosambi function at a LOD score threshold 7.0. The markers were distributed in 19 linkage groups with total coverage of 1,585 cM and mean distance between markers of 3.67 cM. Resistance factors to both diseases were detected: one major QTL for resistance to U. necator and one major and three minor QTLs against P. viticola. RGA- and functional gene-based markers co-locating with the two major QTLs were also identified. This provides first insights about the functional role of those regions. The genetic and molecular information of this map is also being used for physical mapping of the regions involved in the resistance to U. necator and P. viticola. Additionally, the present map is combined with two other maps, for the generation of a consensus map (see Zyprian et al., this conference).