Genetic Analysis of a Segregating Population Derived by a Cross of Welschriesling x Sirius

The population Welschriesling x Sirius (Kl.K1977) derived from a breeding program with the aim of reduction of plant protection. The spring off segregate in the trait of tolerance against powdery mildew (Uncinula necator), downy mildew (Plasmopara viticola), uptake of Mg2+, formation of leaf galls due to Phylloxera attack and erinose. We gained a profound insight into the genetics of this population by genotyping 70 out of 250 seedlings with more than 160 SSR and 190 RAPD markers. We could find seven RAPD markers significantly correlating with the resistance against powdery mildew. The involved RAPD markers show higher significance than SSR markers also correlating to the trait. The effect of a single marker is not very high, hence it can be confirmed that the resistance is based on the coexistence of several related alleles. We could compare the markers from the WR. x Sir. population with markers from a second population (Gr. Veltliner x Seyval =Kl.K1979). While we could not find any coincidence in RAPD markers there were indications that the SSR markers are applicable for both populations. The incidence of severe Mg2+ deficiency symptoms could be caused either by the trait of inefficient Mg uptake inherited from the cultivar Welschriesling or evoked by genetic disturbances of the Mg2+ metabolism. We could find some markers which correlate with the phenomenon of Mg2+ deficiency symptoms of Welschriesling. High significant correlation of Mg deficiency symptoms is given at the locus VMC 105 (internal designation) to the new alleles, which have occurred by mutations. Further SSR markers could be linked to erinose (Eriophyes vitis) sensitivity. Besides the marker analysis we tried to establish a genetic map based on the data gained from SSR genotyping. The first draft of a map showed us that we have to increase the number of vines and markers. Linkage of marker groups is coincident with already published ones.