Archives

? In answer to the increasing market demand, a preliminary cultural and economic trial for cranberry and bilberry crops in Swiss mountain area on neutral to mid-acid soils was carried out by comparing two processes (addition of sulphur and mound culture on wood sawdust) with a control in open soil. To be able to pick in October with the early variety ‘Early Black‘, the cranberry production can be considered in mountain areas up to 800 to 900 m. a.s.l. (1100 m in Valais). The bilberry variety ’Red Pearl’ is not productive enough and other varieties should be tested in mountain area: yields are too low and fruits too small, which causes another increase in picking costs. On a typical soil of mountainous cultivation area with 6.5 pH, an annual addition of sulphur (50 g/m2) allows obtaining favourable conditions for cranberry and bilberry crops. The culture on sawdust did not give satisfactory results. A yield of 1.5 kg/m2 was obtained in Bruson in the 6th production year.

Keywords: cranberry, bilberry, varieties, mountain crop

E-Mail: catherine.baroffio@acw.admin.ch

Adress:

From 2007 to 2009, physiologic and agronomic behaviour of Gamaret was studied under several pedoclimatic conditions of the Vaud area. Twenty five plots were set up with homogeneous material of Gamaret cultivar, and their grapes were vinified separately to carry out chemical and sensory wine analysis. This study aimed to evaluate the influence of the Vaud viticultural area terroirs on the vine-fruit-wine continuum. Despite the effect of climatic factors on vine physiology (precocity of veraison) and must composition (titratable acidity), no clear effect on wine sensory characteristics was evidenced. On the other hand, geopedology clearly influenced vine physiology (water and nitrogen status). During the dry season 2009, the vine water status was significantly different among plots and closely related to soil water holding capacity. Furthermore, the level of vine water status influenced both fruit (berry weight) and wine composition (colour density). Sensory analysis on wines confirmed the positive influence of moderate water constraint during grape maturation. Vine nitrogen status was monitored by measuring yeast assimilable nitrogen (YAN) in the must. YAN varied greatly among plots. Vines grown on soils which limit roots colonization (e.g. compact moraines) tend to have a lower YAN in the must. Vine nitrogen status was thus a key factor for wine quality. Wines made from grapes with low assimilable nitrogen had negative sensory characteristics such as astringency and dry tannins.

Keywords: terroir, vine nitrogen status, wine quality, vine-fruit-wine continuum

E-Mail: jean-sebastien.reynard@acw.admin.ch

Adress:

The agronomical and oenological behaviour of the Vitis vinifera cv. Cornalin was studied in relation to the choice of the rootstock at the Research station Agroscope Changins-Wädenswil ACW, in Leytron (VS). The following rootstocks were chosen for this trial: 3309 C, 5BB, Fercal, 41B MGt, 101-14 MGt and 161- 49 C. The rootstocks mainly influenced the vigour and the mineral uptake of the graft. 41B MGt and 161- 49 C were less vigorous than the other rootstocks. They also had a lower nitrogen and potassium uptake. 41 B presented a high magnesium uptake as well as fewer bunch stem necrosis symptoms whereas 5BB, Fercal and 101-14 MGt had a lower magnesium uptake and more bunch stem necrosis symptoms. The wines issued from the rootstocks 41 B and 161-49 C were slightly more acidic. The rootstock 101-14 MGt appeared to be more sensitive to drought.

Keywords: grape vine, Cornalin, rootstock, mineral nutrition, magnesium deficiency, wine quality

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

Adress:

A comparative analysis of the mechanical properties was conducted on two wine grapes varieties from the Loire Valley (France) differing in color and origin (Chenin and Cabernet franc). The evolution of the texture of the grapes was observed at different stages of maturation with five instrumental methods: double compression 20 %, simple compression 70 %, penetrometry, skin traction and pedicel traction. Overall, the comparison showed that different stages of maturity could be distinguished as well as the varieties and vineyards. Techniques applied to whole-berry features such as compression 20 % and compression 70 % were more effective on the Chenin varieties. On the other hand, skin texture measurement techniques such as penetrometry and skin traction offered at least one parameter that could differentiate dates of maturation in cv. Cabernet franc. Considering all the data, the F-max parameter appeared to be a useful criterion for comparing the two varieties. This study demonstrated that mechanical properties of red and white grapes are significantly different: berry skins of Cabernet franc were more resistant than those of Chenin. To better understand these mechanical differences, an investigation at microscopic and biochemical scale will be undertaken in the near future.

Keywords: grape, mechanical properties, Cabernet franc, Chenin

E-Mail: s.doumouya@groupe-esa.com

Adress: Ecole supérieure d'agriculture d'Angers ESA, F-49007 Angers Cedex 01