QTL mapping of black rot (Guignardia bidwellii) resistance in the grapevine rootstock ‘Börner’ (V. riparia Gm183 × V. cinerea Arnold)

Abstract

In the grapevine cultivar 'Börner' QTLs for black rot resistance were detected consistently in several independent experiments. For one QTL on chromosome 14 closely linked markers were developed and a detailed map provided. Black rot is a serious grapevine disease that causes substantial yield loss under unfavourable conditions. All traditional European grapevine cultivars are susceptible to the causative fungus Guignardia bidwellii which is native to North America. The cultivar 'Börner', an interspecific hybrid of V. riparia and V. cinerea, shows a high resistance to black rot. Therefore, a mapping population derived from the cross of the susceptible breeding line V3125 ('Schiava grossa' × 'Riesling') with 'Börner' was used to carry out QTL analysis. A resistance test was established based on potted plants which were artificially inoculated in a climate chamber with in vitro produced G. bidwellii spores. Several rating systems were developed and tested. Finally, a five class scheme was applied for scoring the level of resistance. A major QTL was detected based on a previously constructed genetic map and data from six independent resistance tests in the climate chamber and one rating of natural infections in the field. The QTL is located on linkage group 14 (Rgb1) and explained up to 21.8 % of the phenotypic variation (LOD 10.5). A second stable QTL mapped on linkage group 16 (Rgb2; LOD 4.2) and explained 8.5 % of the phenotypic variation. These two QTLs together with several minor QTLs observed on the integrated map indicate a polygenic nature of the black rot resistance in 'Börner'. A detailed genetic map is presented for the locus Rgb1 with tightly linked markers valuable for the development for marker-assisted selection for black rot resistance in grapevine breeding.

A Partially Phase-Separated Genome Sequence Assembly of the Vitis Rootstock ‘Börner’ (Vitis riparia × Vitis cinerea) and Its Exploitation for Marker Development and Targeted Mapping

“…Rpv14 was selected as an example for proof of concept because the alternative Rdv1, which causes phylloxera resistance, has already been restricted to an area of about 350 kbp-a value deduced from the physical distance of the published flanking genetic markers (Zhang et al, 2009;Hausmann et al, 2014) relative to the PN40024 reference sequence. The other option, namely black rot resistance mediated by Rgb1/Rgb2, was not selected because there are at least two segregating loci (Rex et al, 2014). We were able to physically reduce the size of the Rpv14 target region to less than 500 kbp.…”

“…It is an interspecific hybrid of V. riparia Gm 183 x V. cinerea Arnold; 'Börner' is thus derived from individuals of two Vitis species native to North America that carry several resistances. Among these are resistances to phylloxera [Rdv1 (Zhang et al, 2009)], black rot [Rgb1 and Rgb2 (Rex et al, 2014)], and to downy mildew [Rpv14 (Ochssner et al, 2016)]. To support the molecular analysis of these and other loci, we generated a first draft genome sequence assembly of the highly heterozygous 'Börner' genome.…”

Programme de collaboration franco-suisse pour la création de nouvelles variétés de vigne durablement résistantes au mildiou et à l'oïdium

“…Relativement peu de travaux ontété consacrés au déterminisme génétique de la résistance au black rot et les connaissances sont encore partielles [20]. Agroscope a néanmoins observé dans ses descendances issues de Bronner une proportion non négligeable d'individus peù a très peu sensibles.…”

Introduction to resistant vine types : a brief history and overview of the situation

“…In European vineyards, black rot (Guignardia bidwellii) is probably the most problematic of these fungi. Therefore, the discovery of two loci carrying resistance to black rot in the Börner rootstock (V. riparia × V. cinerea; Rex et al, 2014) opened the way for a use in future breeding programs. The interest of this approach has recently been confirmed by a screening of many kinds of genotypes, which determined the presence of high-level resistance in several interspecific hybrids and in a seedling from the species M. rotundifolia (Hausmann et al, 2016).…”