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To test the behaviour of Sauvignon clones in Swiss conditions, a trial was set up on the experimental vineyard of Agroscope RAC Changins at Nyon (VD). Five clones of Sauvignon blanc (159, 241, 316, 317 and 378), as well as one clone of Sauvignon gris (917), all from the French Catalogue, were tested. The experimentation did not highlight important differences between the studied clones, except for the weight of the bunches and berries and for the acidity of the must. The acidity was lower for clones 241, 378 and 917.
Key words: Sauvignon blanc, Sauvignon gris, clones, grapevine.

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Adress: Agora

Swiss sweet wines are traditionally elaborated from late harvested grape. The success of this process strongly depends on the weather conditions. Over-ripening of the grapes in the vineyard (late grape harvest), self-enrichment of must by evaporation, cryoextraction and passerillage (raisining) under controlled conditions were compared over three different years. Among the techniques of over-ripening lowest population of acetic and lactic acid bacterias is recorded in the late grape harvest proceed and in the passerillage carried out at high temperature. The malic acid content of grape berries varies according to the temperature of the passerillage. The self-enrichment of the musts gives the wines with the highest levels in acidity and volatile acidity and with the lowest in sulphur dioxide. The compared techniques show significant differences both for sensory quality and chemical composition of sweet wines. The passerillage, carried out under adapted conditions of temperature, gives wines with equivalent quality to those issued from late vintage. The combination between over-ripening and cryoextraction also gives interesting sensory results.
Key words: sweet wines, liqueur-like wines, raisining, passerillage, self-enrichment, cryoselection, late vintage.

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Adress: Agora

The hyssop (Hyssopus officinalis) cultivar «Perlay» is issued of the Agroscope RAC Changins breeding program in Valais. After its first success on mountainous small farm production level it is now grown on larger scale in Switzerland. The cultivar is the result of a hybridization of two subspecies of Hyssopus officinalis L., ssp. officinalis L. from Hungary and spp. canescens (DC.) Nyman from Switzerland (Valais). Characteristic traits of hyssop «Perlay» are an erected, vigorous, homogenous growth type, a mean yield of 6-7 t/ha of dry matter since the second year of production, and an essential oil content of 0.8-1.3% mainly composed of pinocamphon (40-60%), isopinocamphon (20-30%), and ß-pinen (4-15%). It is also a cultivar with a good hardiness and resistance to Sclerotinia sp.
Key words: Hyssopus officinalis, selection, varieties, quality, yield, essential oil.

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Adress: Agora

Anthracnose of marsh-mallow (Althæa officinalis), caused by the fungus Colletotrichum malvarum, was identified as the disease causing considerable damage during the past years in marsh-mallow fields in Switzerland. The host range of the pathogen is limited to a few plant species of the Malvaceae family. It was described for the first time on hollyhock (Althæa rosea), a species closely related to marsh-mallow. The pathogen was seed borne on seeds harvested on a diseased marsh-mallow plant. In contrast, C. malvarum could not be detected on seeds from commercial varieties. Despite this apparent absence of the pathogen on seeds, there are several indications that the spread of marsh-mallow anthracnose during the last years occurred by the seed. Therefore, the seed sanitation is the first step to control this disease.
Key words: anthracnose, Colletotrichum malvarum, hollyhock, marsh-mallow, seed borne.

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E-Mail: vincent.michel@agroscope.admin.ch

Adress: Agora

This study focuses on the use of two molecular analysis techniques including RAPD (Random Amplified Polymorphic DNA) and AFLP (Amplified Fragment Length Polymorphism) in view to provide specific markers for the genetic characterisation of chestnut cultivars in Ticino (Switzerland). 98 and 222 polymorphic bands were amplified through RAPD and AFLP by using 12 and 4 primer combinations respectively. Clustering and principal coordinates analysis upon the two markers allowed to separate the varieties and the coppice sprouts into two clear groups. Identification at cultivar level, however, was not possible. Results obtained with the two molecular markers are comparable. A high significant correlation between RAPD and AFLP data (r = 0.78) was found as well.
Key words: Castanea sativa Mill., chestnut, molecular markers, RAPD (Random Amplified Polymorphic DNA), AFLP (Amplified Fragment Length Polymorphism).

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Adress: Agora

Between 1999 and 2003, a trial on leaf removal Merlot grapevines in the zone of grape bunch growth at end of July (beginning of ripening) was conducted on the experimental estate of the Agroscope RAC Changins in Gudo (Ticino), Switzerland. Two variations, with and without defoliation, were compared on two types of training system (single and double «Guyot» lattice-trained vines). Agronomic, analytical and organoleptic tests were effected. Comparative vinifications were carried out each year of the trial. At identical yields, must sugar content was not influenced by defoliation. The pH, total acidity and malic acid contents of musts tended to be higher (pH) and lower (acidity) in the defoliated variants. Analysis of bottled wines showed that total polyphenols, anthocyans and colour intensity were systematically higher in the wines from defoliated variants. The same wines were also tendencially preferred by wine tasters, with significant differences in 1999, 2002 and 2003.
Key words: grapevine, leaf removal, must and wine composition, wine quality.

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E-Mail: francois.murisier@acw.admin.ch

Adress: Agora

The influence of the harvesting date on must and wine quality has been studied from 1999 to 2002 on the cultivar Garanoir at Agroscope RAC Changins in Nyon (VD). The experiments were designed to compare two harvesting times: when the sugar of the grapes reached 88-90 °Oe and two or three weeks later, about ten days after the harvest of the reference cultivar Gamay. The must of late harvested grapes had a lower content in tartaric acid. As it was found for Gamaret, later harvested Garanoir wines were more coloured and had a higher content in phenolic compounds; they were always preferred in wine testing with their better structure and their tannins of better quality.
Key words: Vitis vinifera, Garanoir, harvesting date, wine quality, phenolic compounds.

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E-Mail: jean-laurent.spring@agroscope.admin.ch

Adress: Agora

To evaluate the nutritive solution recommended for soilless production of sweet pepper with complete drainage recycling, two trials were carried out in greenhouse in 2002 and 2003. The recommended ionic balance used in the nutritive solution was adapted along the cultivation period to adjust the variations of the tap water quality and the composition of the recycled nutrient solution. The analysis of the mineral composition of the plants showed that the proportions of the elements consumed by sweet pepper did not correspond to those provided by the nutritive solution; imbalances were revealed for the elements P, K, Ca and Mg. By decreasing the concentration of P to 1.1 mmol/l and that of Ca to 2.2 mmol/l and by increasing the concentration of K and Mg respectively to 12.5 and 1.3 mmol/l, the composition of the nutritive solution corresponds better to the quantities consumed by the plants and is more adapted for complete recycling system.
Key words: mineral composition, nutrient solution, recycled solution, soilless, sweet pepper.

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Adress: Agora