Molecular characterization of grapevine cultivars of Riesling-type and of closely related Burgundies

Research NoteTen cultivars representing Riesling-type vines and 12 cultivars of the Burgundy family were analyzed by RAPD-PCR. Employing computer programs, similarity degrees were calculated from the RAPD patterns obtained from a set of 20 dekamer primers and used to perform cluster analysis. The Riesling-type cultivars could be differentiated from each other and from the progenitor of a cross Pinot noir x Chambourcin ("Spezial" in Fig.l). With the exception of Aubin blanc, Aubin vert and Elbling white, the Riesling-type cultivars did not show any close relationship. From the Burgundies, Pinot noir, Pinot meunier, Pinot blanc and Pinot gris could not be differentiated. Neither could Chardonnay blanc be differentiated from Chardonnay musque, nor Aligoté from Aligoté vert. Discrimination between the other cultivars was possible. Two Morillon samples from different origins were analyzed and showed clear differences in their RAPD patterns. Furthermore, they seemed to be more similar to Riesling white than to the Burgundies

The effect of homozygosity of locus Rpv12 on downy mildew resistance of grapevine leaves

Inoculation trials with different pathogenic fungi and oomycetes have not yet shown any significant effect of homozygosity in resistance loci on the level of resistance. However, here a considerable reduction in mycelial growth of the oomycete P. viticola was found in association with the homozygous state of the Rpv12 locus. This effect was detected by aniline blue staining of the mycelium after experimental inoculation of leaf tissue and quantified by image analysis. Genotypes homozygous for the Rpv12-locus as classified by SSR marker data, inhibited mycelial growth considerably more in comparison to genotypes carrying the locus Rpv12 in heterozygous state

Molekulare Analyse der Traubenarchitektur (Verbundvorhaben)

In diesem Projekt wurden wichtige phänotypische Kriterien und genetische Grundlagen zu dem komplexen Merkmal der Lockerbeerigkeit erarbeitet. Durch umfangreiche phänotypische Charakterisierung konnte gezeigt werden, dass die Faktoren Rachislänge, Beerenstielchenlänge und Beerengröße die Traubenarchitektur bestimmen. Genetische Determinanten dafür konnten in der Karte aus einer segregierenden Population in QTL Analysen lokalisiert werden. Bei den Spätburgunderklonen und den extrem lockeren Genotypen aus der für Traubenarchitektur spaltenden Kreuzungspopulation führt ein differentielles Wachstum der Infloreszenzen in einer definierten, frühen Entwicklungsphase zur Ausprägung des gewünschten Merkmals der Lockerbeerigkeit. Speziell bei den Spätburgunderklonen konnten Hinweise auf molekulare Mechanismen gefunden werden, die zur Lockerbeerigkeit signifikant beitragen. Mehrere weitere Kandidatengene zur Steuerung der Traubenarchitektur wurden identifiziert

Identification of grapevine cultivars by DNA analyses: Ptfalls of random amplified polymorphic DNA techniques using 10mer primers

Research Not

The role of hairs on the wettability of grapevine (Vitis spp.) leaves

Hairs represent an important physico-chemical factor on abaxial leaf surfaces of grapevine and can influence the wettability of leaves. This was demonstrated by scanning electron micrographs and monitored with a new method using a torsion balance. Forces necessary to remove water droplets of distinct size from leaves were lower in case of pubescent (0,2-0,4 mN) compared to non-pubescent vine leaves (0,4-1,2 mN). Depending on the number of hairs and their surface structure the deposition and distribution of water droplets originating from dew and rain can be prevented due to weak adhesion. Thus, surface features enabling water droplets to pearl off may reduce the probability of infection by fungal spores

Detection of somaclonal variation in grapevine regenerants from protoplasts by RAPD-PCR

Research Not