Identifikation des Mehltauresistenzlocus Rpv10 für die Rebenzüchtung

Ein neuer Resistenzlocus (Rpv10) gegen den Erreger des Falschen Mehltaus an der Rebe (Plasmopara viticola) konnte für die gezielte Nutzung in der Rebenzüchtung erschlossen werden. Die Untersuchungen erfolgten an einer Kreuzungspopulation zwischen dem Zuchtstamm Gf.Ga-52-42 und der Sorte ‘Solaris’ mit 265 F1-Individuen. Über SSR-Markeranalysen wurde eine genetische Karte der Kreuzungspopulation erstellt. Die Varianz der Plasmopara-Resistenz innerhalb der Population wurde durch die Verwendung des Blattscheibentests ermittelt. In den QTL-Analysen ergaben sich bei der Verrechnung der phänotypischen Resistenzdaten mit der genetischen Karte zwei starke QTLs auf den Kopplungsgruppen (LGs) 09 und 18. Der QTL auf LG 09 wurde von ‘Solaris’ in die Kreuzungspopulation eingebracht und erklärt bis zu 50 % der phänotypischen Varianz. Dieser neue, als Rpv10 benannte Resistenzlocus stammt ursprünglich aus der asiatischen Wildart Vitis amurensis. Durch die Neuentwicklung Locus-spezifischer SSR-Marker anhand der Referenzgenomsequenz erfolgte eine Feinkartierung des Rpv10-Locus. Der resultierende QTL-Locus weist ein Konfidenzintervall (1-LOD) von nur noch 0,5 cM in der MQM-Analyse auf. Der korrespondierende Bereich zwischen den QTL flankierenden Markern entspricht 79 kb auf der 12x PN40024-Referenzgenomsequenz. In dieser Region sind ein RGA mit NBS-LRR-Motiv, ein Ethylen-sensitiver Transkriptionsfaktor, ein Protein mit Ankyrin-Domäne sowie eine mutmaßliche Ribonuclease als potentielle Kandidatengene annotiert. Bei dem zweiten starken QTL auf der LG 18 handelt es sich um den bei ‘Regent’ erstmals beschriebenen Rpv3-Locus. Die Genotypen der Kreuzungspopulation, welche sowohl den Rpv3 als auch den Rpv10 Locus aufweisen, zeigen eine signifikant erhöhte Resistenzausprägung. Dies weist auf einen additiven Effekt durch die Pyramidisierung der beiden Resistenzloci hin. Um den Rpv10-Locus in weiteren genetischen Ressourcen zu identifizieren wurden 94 Sorten und Zuchtstämme mit V. amurensis im Stammbaum mit Locus-spezifischen Markern getestet. Dabei konnten 22 Sorten als Resistenzträger ermittelt werden, die in der Resistenzzüchtung als Rpv10-Donor eingesetzt werden könnten. Bei dieser Untersuchung zeigte sich auch, welche SSR-Marker sich am besten für die Verwendung in der markergestützten Selektion (MAS) eignen. Die molekularen Marker zeigten zudem, dass ‘Severnyi’ und nicht wie irrtümlich in der Literatur angenommen ‘Zarya Severa’ ein Großelternteil von ‘Solaris’ ist, über den die Resistenz von V. amurensis eingebracht wurde.Rpv10, a new locus originating from the Asian wild species Vitis amurensis mediates resistance against downy mildew on grapes caused by Plasmopara viticola. This locus was newly identified using a population derived from a cross between grapevine breeding strain Gf.Ga-52-42 and cultivar ‘Solaris’ consisting of 265 F1-individuals. A genetic map of the cross-population was constructed using SSR-Markers and all individuals were screened for downy mildew resistance. Quantitative trait locus (QTL) analysis revealed two major QTL on linkage groups (LGs) 09 and 18. ‘Solaris’ inherited the resistance related locus on LG 09 explaining up to 50 % of the phenotypic variation in the population. This locus, named Rpv10, was further restricted by adding newly developed locus-specific SSR markers. A minimum one-LOD confidence interval of 0.5 cM was achieved in MQM analyses. The region within the flanking markers spans a distance of 1.6 cM corresponding to 79 kb in the 12x reference genome sequence of PN40024. One resistance gene analogue (RGA) of the NBS-LRR type, an ethylene-responsive transcription factor, an ankyrin-like protein and a probable ribonuclease are annotated within this range to be considered as putative candidates for mediating resistance. The major QTL on LG 18 transmitted by Gf.Ga-52-42 is identical to the Rpv3 locus known from ‘Regent’ and ‘Bianca’. The F1 sub-population which contains the Rpv3 as well as the Rpv10 locus showed a significantly higher degree of resistance indicating additive effects by pyramiding of resistance loci. Furthermore, the marker data revealed ‘Severnyi’ as the descent responsible for introgression of the V. amurensis resistance in ‘Solaris’ contradicting the previously assumed derivation. Genetic resources having a V. amurensis background were screened for the Rpv10 genotype. Twenty-two out of ninety-four varieties were identified providing the Rpv10 locus which can potentially be used for implementing the locus into the further breeding progress. This screening also revealed the most suitable SSR-markers for a reliable identification of the Rpv10 locus in marker assisted breeding (MAS)

Relationship between meteorological data, physical-mechanical characteristics of grapes and Botrytis bunch rot

Botrytis bunch rot (BBR) is the economically third most important disease in cool climate viticulture. In order to avoid or delay spreading of BBR infections until the grapes reach physiological ripeness, different management strategies like early defoliation or specific fungicide applications were developed. The scope of most grapevine breeding programs is the selection of mildew fungus-resistant, climatic adapted grapevines with balanced, healthy yield and outstanding wine quality. Within the long-term breeding process, the application of marker-assisted selection (MAS) is the most efficient way for early selection of desired grapevine seedlings. Since no resistances have yet been described for BBR, grapevines shall be selected for developing fruits with physical-mechanical barriers reducing the risk for BBR infection like loose grape bunch architecture and thick, impermeable berry cuticle. In the present study first results regarding the investigation of the relationship between physical-mechanical fruit traits (bunch architecture, berry impedance and berry texture), meteorological data and the degree of BBR infection are shown. Varieties and elite breeding lines were phenotyped using high-throughput, objective sensors in 2021 and 2022, two years with contrasting growing conditions (Siebeldingen, Germany). In comparison to 2021, 2022 was characterized by a higher temperature sum D (+196°days between veraison and harvest) and huge differences in the precipitation sum (PS; -62 mm up to + 105 mm). In order to categorize BBR resistance/ susceptibility, berries from different genotypes showing high variability in their berry characteristics were sampled at maturity and were tested under controlled lab conditions for BBR susceptibility. For some varieties, it could be shown that meteorological conditions affect both, berry traits as well as infection with BBR. In addition to the environment and the training system, physical-mechanical berry traits and the mean berry diameter could be confirmed as promising phenotypic traits for the prediction of BBR resistance. In summary, the consideration of sensor-based physical-mechanical berry traits enables an improved risk prediction for BBR, which is of outstanding importance for the evaluation of breeding material and new varieties growing under different environmental conditions, as well as for phenotyping of mapping populations for QTL analyses and the development of molecular markers. As meteorological conditions were contrasting in 2021 and 2022 and varieties with high phenotypic variability were considered, additional years of investigations are recommended in order to verify the reliability of the detected relationships

Neue molekulare Marker für die Rebenzüchtung zur gezielten Pyramidisierung der Resistenz gegenüber dem Falschen Mehltau (Plasmopara viticola)

Zusammenfassung Molekulare Marker eröffnen neue Möglichkeiten für eine effiziente, zielgerichtete und beschleunigte Züchtung neuer Rebsorten. Von besonderem Interesse sind sie beispielsweise im Hinblick auf die gezielte Kombination verschiedener Abwehrmechanismen in einer Pflanze (Pyramidisierung) zur Etablierung einer hohen und dauerhaften Resistenz. Zu diesem Zweck sollen neue Molekulare Marker für die aus der asiatischen Wildart Vitis amurensis stammenden Plasmopara-Resistenzmechanismen entwickelt und für die Züchtung nutzbar gemacht werden. Stichwörter: Plasmopara viticola; Resistenzzüchtung; Molekulare Marker; Blattscheibentest   Abstract Molecular markers are a superior tool to make grapevine breeding more efficient and faster. A matter of particular interest is to identify the combination of different defence mechanisms in one plant to select durable highly resistant plants. For this case we are developing new molecular markers to detect the resistance mechanisms out of the Asian wild type Vitis amurensis against downy mildew (Plasmopara viticola) to use them in our marker based breeding program. Keywords:Plasmopara viticola; resistance breeding; molecular marker; leaf disc tes

Učinci ranog uklanjanja listova na koncentracije hlapljivih spojeva u Cabernet Sauvignon vinima iz vinogorja Ilok

The aim of this two year study was to evaluate effects of basal leaf removal before blooming on volatile composition of Cabernet Sauvignon wines in the Ilok vineyards (eastern Croatia). During two consecutive vintages (2013, 2014), two different treatments of basal leaf removal were applied: removal of 3 and 6 leaves, and control without leaf removal. Volatile compounds of resulting wines were identified and quantified by gas chromatography coupled with mass spectrometry. Organic acids and higher alcohols remained unaffected by treatments of early defoliation wine, except acetic acid and 2-methyl-6-hepten-1-ol. Early leaf removal was affected on six esters concentration only in the 2014 with different outcome. For compounds unaffected by defoliation, vintage was statistically significant source of variability, as the results of multivariate analysis have confirmed. Defoliation treatments in Cabernet Sauvignon wines from eastern continental part of Croatia should be adjusted to the weather condition in growing season.Cilj ovoga dvogodišnjeg istraživanja bio je procijeniti učinke uklanjanja bazalnoga lista prije cvatnje na sadržaj hlapljivih spojeva Cabernet Sauvignon vina u vinogradima Ilok (istočna Hrvatska). Tijekom dviju uzastopnih godina (2013. i 2014.) primijenjena su dva različita tretmana uklanjanja bazalnih listova: uklanjanje 3 lista, 6 listova te kontrola bez uklanjanja listova. Hlapljivi spojevi dobivenih vina identificirani su i kvantificirani spregnutom tehnikom plinske kromatografije i spektrometrije masa. Tretmani rane defolijacije nisu imali učinka na koncentraciju organskih kiselina i viših alkohola, osim na octenu kiselinu i 2-metil-6-hepten-1-ol. Rana defolijacija utjecala je koncentracije šest estera samo u vinima iz 2014. godine s različitim ishodom. Za spojeve na koje rana defolijacija nije imala učinka, berba je bila statistički značajan izvor varijabilnosti, kao što su rezultati multivarijantne analize potvrdili. Tretmane rane defolijacije u Cabernet Sauvignon vinima u istočnome kontinentalnome dijelu Hrvatske potrebno je prilagoditi vremenskim prilikama tijekom vegetacijske sezone