'Kunbarat' and 'Kunleany' – full not half-siblings

Introduction: The unfortunate introduction of the pathogens Erypsiphe necator (Schwein.) Burr. (Oidium, powdery mildew), Daktulosphaïra vitifoliae Fitch (Phylloxera) and Plasmopara viticola (Berk. & Curt.) Berl. & de Toni (downy mildew) to European viticulture during the 19th century caused West European grapevine breeders to seek for resistance traits. Initially, they investigated interspecific crosses between Vitis vinifera and American Vitis species like V. rupestris or V. riparia (Maul et al. 2019) in searching for resistant hybrids. In Eastern Europe, e.g. Serbia and Hungary, breeders used different genetic resources in their efforts to improve disease resistance. Especially the Asian species V. amurensis Rupr., the Amur grape, was a popular choice for interspecific crosses. Up to date, 71 different V. amurensis descendants and interspecific hybrids between V. amurensis and V. vinifera are reported (Maul et al. 2019). The Amur grape was preferred for breeding not only because of its valuable downy mildew resistance, but also due to its frost tolerance. V. amurensis is adapted to the cold climate of the East Asian region, ranging from Siberia via China to Japan (Wan et al. 2008, koleda 1975). Three different P. viticola resistance loci originating from V. amurensis germplasm (Rpv8, Rpv10, Rpv12) have recently been identified (BlaSi et al. 2011, SchWander 2012, Venuti et al. 2013). In eastern grapevine breeding the Rpv12-carrying genotype 28/19# (Hungary) was crossed and the hybrids were backcrossed with V. vinifera genotypes (koleda 1975, Venuti et al. 2013). A combination of several loci (stacking of loci) is desirable for sustainable maintenance of the resistance trait (Zini et al. 2019). The P. viticola resistance factor Rpv12 is therefore combined with Rpv10 and Rpv3 alleles (the latter from American sources) in grapevine breeding. To accelerate this process, the pedigree of Rpv12 resistance carriers was checked based on molecular (SSR) markers.