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The antagonist property of a Lactobacillus strain (WT2-LAB) against P. ultimum was tested on tomato. The antagonist potential of LAB-WT2 was compared to that of Pseudomonas fluorescens CHA0 (PF-CHA0) whose ability to fight against P. ultimum is recognized. The results show a reduction of plant disease of 90 % with PF-CHA0 while 70 % of reduction were obtained with LAB-WT2. Other tests will be conducted to evaluate the antagonist potential of LAB-WT2 against others Pythium strains present in Swiss agriculture.

Keywords: LAB-WT2, PF-CHA0, biocontrol, damping-off

E-Mail: cedric.camps@acw.admin.ch

Adress:

Considerable progress has been achieved in breeding apple and pear varieties resistant to fire blight. Within the project ZUEFOS (breeding fire blight resistant fruit varieties) the following partners were collaborating: ACW, ETH Zürich, Lubera and Fruture as well as VariCom. 160 varieties and new selections were tested by ACW for their shoot susceptibility. Resistant selections and varieties were considered for new crosses. About 20 000 seedlings resulted from these crosses. Moreover, the resistant but small-fruited wild apples Malus x robusta 5 and ‚Evereste‘ were crossed with high quality cultivars. Two different methods were applied to speed up the generation time. Selected fire blight tolerant varieties and selections are tested for their productivity and market value in four pilot orchards throughout Switzerland.

Keywords: Erwinia amylovora, Malus x domestica, Malus x robusta 5, resistance, breeding

E-Mail: markus.kellerhals@acw.admin.ch

Adress: INRAE, UMR LAE, 68000 Colmar

The aim of the study is to identify the sensory key-drivers on apples in a large scale product space characterised by high sensory diversity. A panel of 15 experts and a panel of 224 French consumers have therefore tasted 31 apple batches (composed of 27 cultivars). The study shows that some clusters of apple consumers are indeed sensitive primarily to the crisp and juicy texture of the product, as it was already shown in the literature. Others pay more attention to the flavour and aroma of apples. Sweetness, ripe and exotic aromas were positively perceived by consumers contrary to the green and acid notes. The study also revealed that the sensory preferences declared by consumers were not always consistent with their hedonic ratings at degustation.

Keywords: sensory analysis, consumption, segments, apples, market

E-Mail: e.mehinagic@groupe-esa.com

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

The aim of this study was to compare different evaluation methods of brown rot blossom blight to determine the most accurate and rapid one. In a second part, the susceptibility of apricot varieties to blossom blight was examinated. An orchard with 68 actual cultivars was artificially inoculated with mummy fruits. From the beginning of the flowering, trees were sprayed 6 times with water (1600 l/ha) in order to increase the relative humidity and to favor inoculation conditions. The most precise evaluation method was the weighing of infested branches. However this method was highly time consuming. Using this method, different susceptibility categories have been defined, allowing to propose low susceptible apricot varieties to the producers.

Keywords: brown rot blossom blight, disease evaluation method, apricot varieties susceptibility

E-Mail: danilo.christen@acw.admin.ch

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A trial on 12 different pedological plots was carried out on the white Vitis vinifera cv. Arvine in Fully (Switzerland). This study pointed out the impact of nitrogen and water availability on the physiology of this grape variety. The N content in the vine positively influenced the vigour, the must composition and the wine quality. A link appeared between the water restriction and the N quantity in the plant. However, the effect of water restriction on the wine quality was less evident in comparison with N. The rate of noble rot (Botrytis cinerea) on grapes in 2011 was positively correlated with the precursor of 3-Mercaptohexanol (R2 = 0.44). The more appreciated Arvine wines of this trial were issued from musts with a pH above 3.10 and a yeast available N quantity above 200 mg/l. The cv. Arvine tolerated very less water restriction, required a high N rate in the leaves (> 2.6 % dry matter) and an important light-exposed leaf area in order to maintain its leaf-fruit ratio above 1.2 m2/kg.

Keywords: cv. Arvine, grapevine physiology, nitrogen nutrition, water restriction, wine quality

E-Mail: thibaut.verdenal@acw.admin.ch

Adress:

Esca disease, which attacks grapevine wood, became increasingly devastating during the past three decades and is a major concern today in all wine-producing countries. This disease is attributed to a group of systematically diverse fungi that are considered to be latent pathogens, even if this is not conclusively established. This study presents the first in-depth comparison between the mycota of healthy and diseased plants from the same vineyard, in order to determine which fungi become invasive as foliar symptoms of esca appear. An unprecedented high fungal diversity, 158 species, appears here in grapevine wood from a single Swiss vineyard plot. An identical mycota inhabits both healthy and diseased adult plants wood with similar frequencies and occurrence of presumed esca pathogens. Pioneer escaassociated fungi are not transmitted from adult to nursery plants through grafting process. Consequently the presumed escaassociated fungal pathogens are most likely saprobes decaying already senescent or dead wood resulting from intensive pruning, frost or other mecanical injuries like grafting.

Keywords: grapevine, esca, young vine decline, ITS, fungal community

E-Mail: valerie.hofstetter@acw.admin.ch

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