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

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

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

Colonization of Different Grapevine Tissues by Plasmopara viticola—A Histological Study

Plasmopara viticola, the downy mildew pathogen, is one of the most important pathogens in European viticulture. This oomycete infects grapevine leaves via zoospores that encyst at stomata. A primary germ tube then enters the substomatal cavity and develops a tubular network of hyphae that proliferate intercellularly and parasitize the leaf mesophyll cells by haustoria. Leaf infections have thus been the primary object of multiple studies concerning the physiology of the pathogen and defense reactions of grapevines. Besides leaves, this oomycete pathogen is able to spread throughout the plant tissue. As shown here by microscopy, it colonizes leaf petioles, shoots, berries and seeds. Evidence is provided showing that this process is facilitated by formation of special fan-shaped hyphae that seem to be necessary to overcome physical barriers in plant tissues. Physical obstacles are mainly constituted by vascular tissue in leaf veins, leaf petioles and shoots. In grapevine shoots, the mycelium seems to extend along the cambial layer between xylem and phloem tissue. Infected young berries are completely colonized on the inside. Older infected “leather berries” show glossy appositions of the fan-shaped hyphae at the inner side of the berry skin. The seeds from that stage of infestation are devoid of endosperm and embryo and biologically dysfunctional. Furthermore, a classification system for P. viticola infection based on the degree of infections in petioles and shoot tips is presented. This study contributes to a better understanding of downy mildew pathogenesis in grapevine, a prerequisite for efficient control measures

Make or buy : IT-based decision support for grid imbalance settlement in smarter electricity networks

AbstractDecision (support) systems are a particularly important type of information system to energy informatics. A key challenge in energy informatics is that electricity supply must be in balance with demand at all times. More volatile renewable energy sources increase the relevance of electricity network balancing, i.e., imbalance settlement. Typically, electricity distribution network operators bought balancing power from external service providers (Buy option). Interestingly, however, more local energy resources help smarter electricity networks develop a Make option, as in our real-world evaluation. Choosing the better decision alternative within the relevant timeframes challenges human decision-making capabilities. Therefore, this research proposes a model-based decision system to improve the operators’ decisions concerning Make or Buy under various levels of data quality represented by availability, granularity, and timeliness. The study reports savings up to 40% of costs for imbalance settlement supporting ambitious development efforts by the municipality we study in our real-world evaluation.</jats:p