Search

Viticulture is of high economic value. Traditional grapevine cultivars (Vitis vinifera L.) are used in adaptation to the climatic conditions from Northern to Southern European growing areas. However, the recent trend of global warming causes quality deficits due to a shift of the plant's development to earlier times in the year. As a consequence, premature ripening happens under warm temperatures and interferes with the balanced accumulation of sugars, acids, aroma profiles and berry coloration. Modern grapevine breeding is challenged to include the ripening behavior as an important trait (besides pathogen resistance and other characteristics) into the development of novel cultivars well suited for sustainable viticulture. Breeders nowadays apply molecular markers to follow the introgression of desired traits on the genetic level. Previous work has identified a molecular tag on grapevine chromosome 16 strongly linked to the time of véraison, the start of the second phase of berry ripening, in a segregating cross population. In this study we analyzed the transferability of this marker to a set of 36 grapevine cultivars commonly used in German viticulture. Association analysis verified the predictive character of the time point of véraison for maturation time and confirmed the diagnostic potential of the véraison-linked marker in this extended set of cultivars., VITIS - Journal of Grapevine Research, Vol 57 No 3 (2018): Vitis

The Vitis vinifera background of 'Catawba' and 'Concord' was investigated by using SSR analysis: 'Sémillon' was shown to be an ancestor of 'Catawba', while the wild parent remains unknown. 'Concord' was confirmed to be an offspring of 'Catawba' and another unknown wild parent. Since these two important American varieties most likely resulted from random natural crosses and successful selection, the original, wild growing wild donors remain unknown., VITIS - Journal of Grapevine Research, Vol. 55 No. 2 (2016): Vitis

Die vorliegenden Untersuchungen aus den Jahren 1978-1980 befassen sich mit dem Einfluß der Wasserversorgung auf den Gaswechsel traubentragender und vegetativ wachsender Reben der Sorten Müller-Thurgau und Bacchus. • Die Nettophotosyntheserate wird durch eine herabgesetzte Wasserversorgung im Mittel aller Meßreihen um 27 % reduziert. Es zeigt sich eine Abhängigkeit von der Länge der Trockenphase, wonach sich mit zunehmender Dauer der Trockenperiode di.e Reduktion der Nettophotosyntheserate verringert. • Die Traube verursacht eine Steigerung der Nettophotosyntheserate, wobei dieser Effekt in der Feuchtkultur mit durchschnittlich 11 % größer ist als in der Trockenkultur mit durchschnittlich 6 %. Die Nettophotosyntheserate traubentragender Pflanzen ist in der Beerenentwicklungsphase III am stärksten erhöht. • Bodentrockenheit bedingt eine Verminderung der Transpiration um durchschnittlich 39 %. Der Einfluß der Traube auf die Transpiration ist lediglich in der Feuchtkultur mit einer Steigerung von 5 % angedeutet. • Das Verhältnis von Nettophotosyntheserate zu Transpirationsrate und somit die „Produktivität der Transpiration" ist durch eine reduzierte Wasserversorgung um durchschnittlich 20 % gesteigert. Die Traube erhöht die „Produktivität der Transpiration" um 6 %. • Der Transpirationskoeffizient wird durch Bodentrockenheit deutlich verringert. Traubentragende Reben zeigen ebenfalls eine Tendenz zu kleineren Transpirationskoeffizienten. Die Sorte Müller-Thurgau hat im Vergleich zu Bacchus einen gesichert höheren Transpirationskoeffizienten. • Die ermittelten Gaswechselmeßwerte lassen mit einem Bestimmtheitsmaß von 90 % einen Schluß auf den Transpirationskoeffizienten zu. Influence of water supply on growth, gas exchange and substance production of fruit-bearing grapevines II. Gas exchange The present investigations deal with the influence of water supply on gas exchange of Müller-Thurgau and Bacchus vines, both with and without clusters. • A reduced water supply causes an immediate reduction of 27 % of the rate of net photosynthesis throughout all experiments. However, during longer lasting drought periods the rate of net photosynthesis recovers, leading to somewhat lesser rates than those of the control plants. • The presence of clusters enhances the rau; of net photosynthesis. This enhancement is more pronounced with well watered plants (11 %) than in dry-cultivated ones (6 %). The effect of clusters on the net rate of photosynthesis is most pronounced at stage III of berry development. • Soil drought causes a reduction of the rate of t ranspiration by 39 %. The influence of the cluster on t ranspiration can only be intimated with well watered plants to a maximum increase of 5 %. • The ratio of the net photosynthesis and transpiration rates what is called as the "productivity of transpiration", increases to an average of 20 % due to a reduced water supply. The cluster raises the "productivity of transpiration" by 6 %. • The transpiration coefficient is reduced significantly by soil drought. Cluster-bearing plants have a lower transpiration coefficient. Compared to Bacchus, Müller-Thurgau shows a significantly higher transpiration coefficient. • A high positive correlation exists between the gas exchange measurements and the transpiration coefficient., VITIS - Journal of Grapevine Research, Vol. 23 No. 1 (1984): Vitis

Die vorliegenden Untersuchungen aus den Jahren 1978-1980 befassen sich mit dem Einfluß der Wasserversorgung auf das vegetative Wachstum traubentragender und vegetativ wachsender Reben der Sorten Müller-Thurgau und Bacchus. • Eine herabgesetzte Wasserversorgung führt zu einer Reduktion des Trieblängenwachstums, der Blattzahl und der Blattfläche. Aus der relativ stärkeren Hemmung des Trieblängenwachstums und der Blattflächenentwicklung im Vergleich zur Blattzahl resultiert eine geringere mittlere lnternodienlänge und Blattgröße trocken kultivierter Pflanzen. • Bei Anwesenheit von Trauben wird der Zuwachs von Trieblänge, Blattzahl und Blattfläche reduziert. Dieser Effekt wird durch Bodentrockenheit verstärkt. • Die wachstumshemmende Wirkung einer geringen Wasserversorgung ist bei der Rebsorte Bacchus geringfügig (um etwa 5 % ) stärker ausgeprägt als bei MüllerThurgau. Influence of water supply on growth, gas exchange and substance production of fruit-bearing grapevines 1. Vegetative growth The present investigations deal with the influence of water supply on the vegetative growth of Müller-Thurgau and Bacchus vines, both with and without clusters. • A reduced water supply leads to a reduction in shqot growth, number of leaves and leaf area. A lower mean length of internodes and leaf size of dry-cultivated plants results from the somewhat stronger inhibition of shoot growth and development of leaf size compared with number of leaves. • The presence of clusters reduces the shoot length, leaf number and leaf area. Dryness of soil intensifies this effect. • The growth inhibitory effect of a lower water supply is slightly more pronounced in the variety Bacchus (about 5 % more) than in Müller-Thurgau., VITIS - Journal of Grapevine Research, Vol. 22 No. 3 (1983): Vitis

The influence of water supply of fruit-bearing and vegetatively growing vines on dry matter production and on yield and quality has been investigated during the years 1979 and 1980. • Dry matter production is significantly reduced by soil drought, root growth being less influenced than shoot growth. Comparing weil watered plants with dry-cultivated ones, no differences are found in the total production of vegetatively growing and fruit-bearing vines. The fruit, however, reduced the dry matter production of all vegetative organs, particularly root growth under drought conditions. Despite reduction of the vegetative growth the total amount of shoot and cluster weight of fruit-bearing vines is in all cases higher than shoot weight of vegetatively growing plants. • The different effect of drought and fruit production on shoot and root growth caused a pronounced alteration of the shoot-to-root ratio : This ratio being low at a low water supply, and high in fruit-bearing plants. • A significant correlation between net photosynthesis and net assimilation rates was obtained. The correlation coefficients range between r = +0.90 and r = +0.95. • An optimum water supply during growth stage I of the grape berry results in a significant increase of yield via increased single-berry weight whereas no increase in yield (Müller-Thurgau) or only a slight increase (Bacchus) occurs when drought conditions during stage III of berry growth are counteracted by a surplus watering. • A sufficient water supply, particularly in stage I of berry growth, leads to an increased acid content of the berry., VITIS - Journal of Grapevine Research, Vol. 24 No. 3 (1985): VITIS

1-year-old grapevine cuttings (cvs. Gf Ga-58-30, Fr 993-60, Riesling, Kerner) were grown in a greenhouse in pots at four levels of nitrogen supply, in order to test their resistance to powdery mildew, downy mildew, and their possible stilbene synthesis. Our most significant findings are that: • increased rates of nitrogen supply decrease the degree of resistance against powdery and downy mildew and phytoalexin (stilbene) synthesis; • the hybrids (Gf Ga-58-30 and Fr 993-60) show a higher powdery and downy mildew resistance and a higher stiloene synthesis than the V. 11inifera varieties (Riesling and Kerner); • the amount of stilbene (resveratrol and E-viniferin) increases during the growing cycle., VITIS - Journal of Grapevine Research, Vol. 26 No. 4 (1987): VITIS

Investigations on the heritability of resistance to Oidium tuclceri, Plasmopara viticola and Botrytis cinerea in grapes In the years 1985-1987 investigations on progenies of interspecific crossings were carried out in order to ascertain the heritability of resistance to Oidium tuckeri, Plasmopara viticola and Botrytis cinerea (formation of stilbene). Results from testing the resistance in the field and in vitro were closeley correlated and allowed therefore to check the degree of resistance in vitro under standardized conditions. The coefficients of heritability in the narrow sense calculated for 0. tuckeri range from 0.31 to 0.51, for P. viticola from 0.26 to 0.39 and for the formation of stilbene from 0.23 to 0.26. According to these results, the resistance to 0. tuckeri is most strongly influenced by additive gene effects. The high coefficients of heritability in the broad sense lying between 0.82 and 0.95 for all the investigated characters indicate little environmental dependence. Investigations on a seed!ing population of the Asian wild species Vitis yeshanensis point to a monogenic respectively oligogenic mechanism of resistance. The usage of this resistance for breeding purposes as a complement to the establishment of a stable horizontal resistance is discussed., VITIS - Journal of Grapevine Research, Vol. 28 No. 4 (1989): VITIS

The analysis of the offspring of 6 crossings with a total of 360 genotypes revealed that, of a total of 13 characteristics taken into account by the investigations, only the yield or the yield components, the beginning of berry ripening and the degree of botrytis infection have a significant influence on the sugar content of the must. About 60% of the fluctuations in the sugar content of the must could be explained by these, whereby at approx. 35% the beginning of berry ripening accounted for the highest percentage. The coefficient of determination for the three yield parameters which were investigated was between 12 and 19%. The weight of the berries was the most important factor, while the number of clusters per shoot was nearly neutral with respect to its effect on the sugar content of the must. Consideration of these relations when selecting seedlings may, if only to a limited extent, lead to an increase in the success of selection for varieties with a high sugar content. It should be mentioned that these results, which were reached under the climatic conditions of Central Europe, cannot necessarily be applied to wine growing areas in other climates. Some of the heritability levels determined differ considerably for the individual characteristics. While a low heritability coefficient was ascertained for the number of clusters per shoot, the single berry weight and the beginning of berry ripening indicate a high percentage of additive genetic effect, i.e. their degree in the offspring can be influenced to a great extent by the selection of the parents for crossing combinations. By taking into account both the heritability levels when making the crossing combinations and the relations between these characteristics and the sugar content of the berries when selecting, a breeding programme to increase the sugar content is likely to make rapid progress. In addition, the selection criteria pointed out may be useful in clonal selection with regard to better quality. Last but not least, values for combining ability, which can be calculated by a similar model of variance analysis, may help by the identification of varieties., VITIS - Journal of Grapevine Research, Vol. 29 (1990): Vitis (Special Issue)

‘Heunisch Weiss’ (syn. ‘Gouais blanc’) contributed to a considerable increase of our varietal assortment, including renowned varieties like ‘Chardonnay’ and ‘Riesling Weiss’. Three phenotypic variants of ‘Heunisch Weiss’ were discovered in the grapevine collection at the JKI Institute for Grapevine Breeding Geilweilerhof: (a) ‘Heunisch Dreifarbig’ (three coloured ‘Heunisch’; VIVC prime name ‘Heunisch Dreifarbig’) expressing intense anthocyanin coloration on shoots, inflorescences and leaf petioles before fruit set and even red berry skin at fruit set stage; (b) ‘Pekasore’ (VIVC prime name ‘Heunisch Rotgestreift’; red striped ‘Heunisch’;) with rose to red stripes on white berries and (c) the stenospermocarpic ‘Aspirant’ (VIVC prime name ‘Heunisch Weiss Seedless’). Four cultivars proving to be homonymous in relation to ‘Heunisch’ were investigated at 24 loci to determine their identity or relatedness to ‘Heunisch Weiss’, respectively. ‘Heunisch Schwarz’ turned out to be a ‘Heunisch Weiss’ offspring. No parent offspring relationship was detected for ‘Heunisch Rot’, ‘Haenisch Rot’ = ‘Pamid’, and ‘Heunisch Blau’ . Ampelographic description was carried out for some of the accessions to trace back historical evidences. In addition five new ‘Heunisch Weiss’ offsprings were identified and confirmed by analysing 35 nuclear microsatellite loci. The accession ‘Furmint Apiren’ turned out to be a seedless bud mutant of the ‘Heunisch Weiss’ offspring ‘Iordan’., VITIS - Journal of Grapevine Research, Vol. 54 No. 2 (2015): Vitis

During 1991 through 1993 a total of 475 cvs were rated for oidium infection of leaves and berries. It was established that there was no infection of the berries of 41 cvs and on the leaves of one cultivar. A comparison with the V. vinifera cvs Müller-Thurgau and Silvaner clearly shows that an impressive number of genotypes have a substantially lower degree of infection. The wide genetic variation offers a good basis upon which new cvs with improved oidium resistance can be bred. Despite the significant correlation between oidium infection on leaves and berries, there was, in many cases, considerable variation in leaf infection within one level of berry infection, or in berry infection within one level of leaf infection. Therefore, a precise conclusion as to the resistance of berries can not be made on the basis of screening procedures in the greenhouse or in vitro to determine the degree of resistance on leaves., VITIS - Journal of Grapevine Research, Vol. 33 No. 3 (1994): Vitis

The practical application of pyramiding resistance genes by the use of molecular markers was investigated in a F1 progeny derived from the cross of VHR 3082-1-42 x ‘Regent’. VHR 3082-1-42 is a cross between Muscadinia rotundifolia x Vitis vinifera, backcrossed another four times with V. vinifera (PAUQUET et al. 2001). It carries the Run1-gene which causes resistance to powdery mildew and the Rpv1-gene which is related to resistance against downy mildew. Both genes were introduced from Muscadinia rotundifolia (BOUQUET et al. 2000; WIEDEMANN-MERDINOGLU et al. 2006). ‘Regent’ is a new cultivar with quantitative resistance against downy and powdery mildew (EIBACH and TÖPFER 2003) released in Germany in 1996 for commercial use. 119 individuals of the F1 progeny were screened with a molecular marker for the Run1-gene (DONALD et al. 2002), with two SSR-markers for the Rpv1-gene (WIEDEMANN-MERDINOGLU et al. 2006) and with several markers from ‘Regent’ that showed good correlation to powdery and downy mildew resistance (ZYPRIAN et al. 2002, SALAKHUTDINOV et al. 2003, AKKURT 2004, FISCHER et al. 2004, AKKURT et al. 2007). Phenotypic evaluation for downy mildew resistance was done by artificial inoculation of leaf discs, and for powdery mildew by natural infection in a greenhouse. Comparison of the phenotypic data with the results of the molecular marker analyses showed a clear correlation between the degree of resistance and the presence of the resistance related alleles. According to the phenotypic data, 20 genotypes of the offspring were free of powdery and downy mildew infections. Based on a marker-assisted evaluation, out of these 20 genotypes a subset of four carried all the resistance related alleles for powdery and downy mildew indicating that resistance genes from both parents were effectively combined., VITIS - Journal of Grapevine Research, Vol. 46 No. 3 (2007): Vitis

Organizing SSR markers located on one chromosome into PCR multiplexes has the potential to reduce the costs of marker analysis. The optimal selection strategies for such chromosome-wise multiplexes have not yet been investigated. We investigated with computer simulations three different selection strategies for gene introgression with a pseudo-backcross scheme and a marker density of one marker every 10 cM. Selecting individuals with the highest number of chromosomes carrying V. vinifera alleles at all background marker loci reduced the number of required multiplexes by 7.24-7.87 % in generations pBC4-pBC6 for population sizes nt = 150-300 individuals per pseudo-backcross generation., VITIS - Journal of Grapevine Research, Vol. 52 No. 4 (2013): Vitis

North American Vitis labrusca vines carry properties such as disease resistances, morphological cluster ad berry traits or flavors which make the species interesting for grapevine breeding. Using it as a source for resistance breeding, undesired metabolic properties like off-flavors will also be inherited. On the other side, organoleptic analysis revealed also interesting flavor expressions. This study aimed at characterizing genetically and morphologically 21 V. labrusca hybrid accessions available in the germplasm collection at Geilweilerhof as well as defining their relations. Genetic fingerprinting was conducted by SSR marker analysis. For phenotypic characterization, mainly leaf and bunch morphology were considered. Furthermore total anthocyanin and phenol content of the berry skins were analyzed. The juices were examined concerning quality determining parameters. Amongst others, data of the sugars, acids and aroma compounds were obtained. Additionally, sensory evaluations were performed by an experienced test panel. Data for 18 of the accessions from Geilweilerhof are also available in the USDA database at Geneva, United States. Both sets of data were compared in terms of genetic fingerprint and morphology. This comparison elucidated some inconsistencies suggesting misnaming of some accessions in the germplasm collection of the Institute for Grapevine Breeding Geilweilerhof. But also formerly supposed ancestries were confirmed to be incorrect as the pedigree `Concord´ x `Catawba´ for the variety `Caco´. These findings enrich our knowledge about genetic resources of V. labrusca and put it closer to be used in grapevine resistance breeding.

Fragestellung/Einleitung: Aus tierschutzrechtlichen Aspekten kann die Nahtübung der modifizierten Bühner-Naht zur Fixierung eines Vaginalprolaps (Technik nach Bickhardt 1993) [ref:1], nur von einer begrenzten Anzahl an Studierenden und nicht mehrmals am selben lebenden Tier[for full text, please go to the a.m. URL], Jahrestagung der Gesellschaft für Medizinische Ausbildung (GMA)

Fragestellung/Einleitung: Chirurgische Kurse bieten den Studierenden die Möglichkeit, sowohl ihre praktische Kompetenz als auch ihre Fähigkeit zur korrekten Selbsteinschätzung ihrer Kompetenz zu verbessern[ref:1], [ref:2]. Mittels objektiver strukturierter klinischer[for full text, please go to the a.m. URL], Jahrestagung der Gesellschaft für Medizinische Ausbildung (GMA)

International audience; To answer the new challenges faced by viticulture, grapevine breeding major goal is to create new cultivars integrating both resistance against pathogens and adaptation to climatic changes while still offering high quality final products. These traits have to be accumulated from different sources, several Vitis species for resistance to biotic and abiotic stresses and V. vinifera for quality. Compared to other crops, the genetic bases of the variability of these complex traits are still poorly understood in grapevine, in particular because searching for QTLs in perennial woody species is very long, tedious and costly. Applying association genetics at the whole genome scale (genome-scan) will permit to more rapidly and efficiently identify the main genetic factors underlying the variation of agronomically important traits, by taking advantage of the high variability and recombinations accumulated within the available genetic resources. Precise knowledge of the structure of genetic diversity and linkage disequilibrium (LD) in study samples is crucial to design and perform association genetics studies. The DLVitis project aims at producing this knowledge for 4 Vitis species of interest to breeding, V. vinifera and 3 american species, V. riparia, V. cinerea and V. aestivalis. Its main objectives are : - to characterize the structure of genetic diversity within populations of the 3 American species - to characterize LD between SNPs in 4 genomic regions of 2 Mb each, in 4 samples of V. vinifera and 1 population of each of the 3 American species to locally test genome-scan for two traits, resistance to downy mildew and berry size.

International audience

International audience; Genome-wide association (GWA) genetics is potentially of great interest in grapevine to much more rapidly and efficiently find the main loci (QTLs) and alleles involved in the variation of traits of interest to breeding, compared to searches based on individual segregating progenies. Knowledge of the structure of genetic diversity and linkage disequilibrium (LD) is a necessary prerequisite to design association genetics studies. Vitis vinifera genetic diversity and structure are already well characterized, but LD in this species has not been thoroughly estimated yet. Other Vitis species are a large potential source of resistance to biotic and abiotic stresses for introgression into V. vinifera, but relatively few genetic resources are available in germplasm repositories and the genetic diversity of these species is hardly known. The objectives of the DLVitis project (ANR 2009-2011) are to assess genetic structure and linkage disequilibrium in V. vinifera and 3 American species (V. riparia, V. cinerea, V. aestivalis). For V. vinifera, 3 samples of 93 cultivars were defined, based on available SSR data, by minimizing structure and kinship and maximizing genetic distances. An additional sample of 93 accessions of wild V. vinifera (subsp. silvestris) was also defined. For each American species, 150-200 seeds were collected in natura last autumn. Genetic diversity and structure will be assessed this year using SSRs, and a sample of 93 accessions will be defined for each species. Four genomic regions of 2 Mb each were chosen to estimate LD between specific SNPs in ca. 1 gene out of 3 in each sample of 93 individuals described above. Novel estimates of LD taking structure and kinship into account were developped and will be presented. The first results obtained in V. vinifera in 2 genomic regions showed differences in the rate of LD decay between samples and regions, suggesting past occurrence of differential selection. The consequences of these results for the design of GWA studies will be discussed.