R-Loci Arrangement Versus Downy and Powdery Mildew Resistance Level: A Vitis Hybrid Survey

Abstract

For the viticulture of the future, it will be an essential prerequisite to manage grapevine diseases with fewer chemical inputs. The development and the deployment of novel mildew resistant varieties are considered one of the most promising strategies towards a sustainable viticulture. In this regard, a collection of 102 accessions derived from crossing Vitis hybrids with V. vinifera varieties was studied. In addition to the true-to-type analysis, an exhaustive genetic characterization was carried out at the 11 reliable mildew resistance (R) loci available in the literature to date. Our findings highlight the pyramiding of R-loci against downy mildew in 15.7% and against powdery mildew in 39.2% of the total accessions. The genetic analysis was coupled with a three-year evaluation of disease symptoms in an untreated field in order to assess the impact of the R-loci arrangement on the disease resistance degree at leaf and bunch level. Overall, our results strongly suggest that R-loci pyramiding does not necessarily mean to increase the overall disease resistance, but it guarantees the presence of further barriers in case of pathogens overcoming the first. Moreover, our survey allows the discovery of new mildew resistance sources useful for novel QTL identifications towards marker-assisted breeding.

Behavior of Vine Varieties Resistant to Fungal Diseases in the Somontano Region

“…The decrease in downy mildew incidence along the season may be tentatively attributed to increases in temperature [32]. In 2018, downy mildew attack was detected both in leaves ( Figure 2c) and in clusters (Figure 2d).…”

“…The decrease in downy mildew incidence along the season may be tentatively attributed to increases in temperature [32].…”

“…The third PIWI variety, Muscaris (FR 493-87) was also obtained by the Stainliches Weinbauinstitut Freiburg in 1987 from the cross of Solaris × Gelber Muskateller [31]. The resistance loci were Rpv12 for Sauvignon Kretos; Rpv3.3, Rpv10, Ren 3 and Ren 9 for Souvignier gris; and Rpv10, Ren 3 and Ren 9 for Muscaris [32].…”

Integrating metabolomics and targeted gene expression to uncover potential biomarkers of fungal/oomycetes-associated disease susceptibility in grapevine

“…Several crossing lines inbreed with American Vitis species are currently commercialized as partially resistant varieties to fungal pathogens, e.g. Regent, Calardis Blanc, Solaris 8,9 .…”

Rpv29, Rpv30 and Rpv31: Three Novel Genomic Loci Associated With Resistance to Plasmopara viticola in Vitis vinifera

“…Finding new sources of resistance is of paramount importance in breeding for biotic stress resistance in a perennial crop, which has to be productive for years while maintaining its resistance characteristics at the same time: the main strategy for preventing the selection of pathogen strains able to overcome resistance is, in fact, pyramiding resistance genes in the crop variety ( Eibach et al, 2007 ; Delmotte et al, 2016 ; Zini et al, 2019 ). Recently, unique resistance traits to the downy mildew agent have been reported in V .…”