ISHS FRUIT SECTION
Grape Working Group
International Workshop on Advances in Grapevine and Wine Research
Venosa (Italy),
September 15 - 17, 2005
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INVITATED SPEAKERS
Initial observations on the berry size and yield paradigms of winegrape quality. Mark Allen MatthewsDepartment of Viticulture and Enology, University of California, Davis, CA 95616
Berry size and crop yield are widely acknowledged as important factors determining winegrape quality. This lecture will report on recent research that addresses both parameters and the interactions between them in presence and absence of water deficits. When fruit from different irrigation treatments were separated into size categories prior to analysis, the results showed that there are effects of vine water status on fruit composition that arise independent of the resultant differences in fruit size. Water deficits increased the amount of skin tannin and anthocyanin per berry and the concentrations of skin tannin and anthocyanins, but did not significantly affect the content or concentration of seed tannin. The effect of vine water status on the concentration of skin tannin and anthocyanin was greater than the effect of fruit size. To optimize crop level, it is essential to have an estimate of the amount of clusters that a vine can reasonably bring to ripening and to determine how the timing of ripening is dependent upon crop level. When crop level was altered several fold by establishing a high crop load and thinning to different numbers of clusters at veraison, berry size was largely unaffected, but the time required to reach 23.5 , 24, and 25 °Brix was linearly dependent on crop level. When crop level was altered several fold by that cluster thinning method and by pruning, the pruning treatments had a much larger effect on the sensory properties of the resulting wines than the mid-season thinning treatments. As node number increased by winter pruning, fruity attributes increased in intensity and vegetal attributes decreased in intensity. In a separate study of the impact of irrigation, the low yielding vines (low irrigation) produced wines with the most fruity and least veggie sensory notes. Thus, the relationships of irrigation-adjusted yield to sensory attributes were the inverse of the relationships for pruning-adjusted yield. Therefore, the viticulture practices used to control yield in a vineyard may be more important than the yield values per se in determining the sensory properties of the resulting wines.Yeast/vine interaction as selection tool to optimize wine typicality
Romano Patrizia
Dipartimento di Biologia, Difesa, Biotecnologie Agro-Forestali, Universitą della Basilicata, Viale dell’Ateneo Lucano 10, 85100 Potenza (Italy), e-mail: pot2930@iperbole.bologna.it// romano@unibas.it
This lecture will emphasize the significant of biodiversity in Saccharomyces cerevisiae on the selection of starter cultures able to complement and optimize grape quality in order to obtain a wine in which the optimal interaction yeast/vine can maintain the local environmental identity.
Influence of Nutrient Composition in Grape Must on Alcoholic and Malolactic Fermentation and Wine Quality
Doris Rauhut
Department of Microbiology and Biochemistry, State Research Institute Geisenheim, Von-Lade-Strasse 1, D-65366 Geisenheim, e-mail: Doris.Rauhut@fa-gm.de
Results from recent research trials indicated that the nutrient composition in the grape must and the chosen yeast strain for alcoholic fermentation has a great impact on malolactic fermentation and also on sparkling wine production. The effect of different nutrient additions to various musts on fermentation and on the composition of volatile and non-volatile compounds in the final product will be presented with selected examples.
Perceived astringency in wine: a predictive model
Erminio Monteleone
Dipartimento di Biologia Difesa e Biotecnologie Agro Forestali, Universitą degli Studi della Basilicata, Potenza, e-mail:monteleone@unibas.it.
In this work recent advancements in predicting astringency induced by phenolic compounds are discussed and new and promising methods are presented. Critical points in collecting both sensory and chemical data are reviewed. In particular, the application of the "Mucin Index Assay" (MIA) in predicting the astringency induced by grape and wine phenol extracts is shown. The results of the use of the MIA on commercial phenolic extract, seed phenolic extracts from Aglianico grape, 18 Sangiovese experimental wines and 20 commercial Aglianico del Vulture wines are presented.
The Health Benefits of Wine
Giuseppe (Joe) Mazza
Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, British Columbia, CANADA, e-mail: mazzag@agr.gc.caThis presentation will address recent advances and limitations of the research on the health benefits of wine, with a focus on the epidemiological and molecular basis for the health benefits of red wine. Results from recent human trials on absorption and bio-availability of anthocyanins will also be presented.
Actual and possible impact of grapevine local varieties on viticulture Attilio Scienza
Dipartimento di Produzione Vegetale – Universitą di Milano (I); attilio.scienza@unimi.it
Patterns concerning the origin of the Italian variety assortment will be presented and discussed with particular emphasis on the genetic variability among varieties and within varieties. On these bases, strategy for local major and minor germplasm exploration and recovery will be presented. Some case studies for different viticultural and enological models will be presented
Effect of irrigation and fertilization on fruit and wine quality
Ben Ami Bravdo
The Robert H. Smith Institute of Plant Sciences&genetics in Agriculture, The Hebrew University of Jerusalem. Israel, e-mail: bravdo@agri.huji.ac.ilThe OIV (International Organization of Vine and Wine) has recently adopted a resolution that supports irrigation of winegrapes provided it is being used for regulating vigor and production (resolution viti 2/2003). Moreover, the use of fertigation enables to control the concentration and the composition of various mineral elements in the major root zone since plant roots take up minerals according to concentration gradients rather than to amounts per Ha. Since various flavor and aroma compounds are formed at different stages of growth and development, it is possible to affect the biosynthesis and accumulation of each of them by regulating the vegetative growth at each stage and thereby reducing sink competition between vegetative growing tips and developing fruits.
The effects of irrigation and mineral nutrition on fruit and wine quality will be presented in this lecture with selected examples.
The issue of canopy efficiency in the grapevine: assessment and approaches for its improvement.
Stefano Poni
Istituto di Frutti-Viticoltura, Universitą Cattolica del Sacro Cuore, via Emilia Parmense, 84 29100 Piacenza, Italy. E-mail: stefano.poni@unicatt.itIn this review paper we will address different methods available to evaluate the efficiency of different canopy types including traditional source-to-sink indices, direct measurements of whole-canopy structure and gas exchange, and modelling. Thereafter, a few examples of growing systems able to improve canopy efficiency will be provided with major emphasis put on leaf distribution an demography, regulation of leaf-t-fruit ratio throughout the season, micro-environmental conditions that might enhance accumulation of sugar, pigments and aromas into the berry.
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Programming: Giuseppe Montanaro