Investigations about the influence of some physiological and phenological characteristics on quality and their heredity

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

Investigations about the genetic resources of grapes with regard to resistance characteristics to powdery mildew 8Oidium tuckeri)

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

Investigations on the influence of N fertilizer on resistance to powdery mildew (Oidium tuckeri) downy mildew (Plasmopara viticola) and on phytoalexin synthesis in different grapevine varieties

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

The use of molecular markers for pyramiding resistance genes in grapevine breeding

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.

The prolific grape variety (Vitis vinifera L.) ‘Heunisch Weiss’ (= ‘Gouais blanc’): bud mutants, “colored” homonyms and further offspring

‘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’

Selection strategies for marker-assisted background selection with chromosome-wise SSR multiplexes in pseudo-backcross programs for grapevine breeding

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.

Grapevine breeding under climate change: Applicability of a molecular marker linked to véraison

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

Einfluß der Wasserversorgung auf Wachstum, Gaswechsel und Substanzproduktion traubentragender Reben I. Das vegetative Wachstum

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 grapevines1. Vegetative growthThe 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

Einfluß der Wasserversorgung auf Wachstum, Gaswechsel und Substanzproduktion traubentragender Reben II. Der Gaswechsel

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 grapevinesII. Gas exchangeThe 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

Einfluß der Wasserversorgung auf Wachstum, Gaswechsel und Substanzproduktion traubentragender Reben III. Die Substanzproduktion

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