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EFS12- Book of abstracts - Contact

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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS<br />

Wheat monitoring in Switzerland: Which cropping<br />

factors influence occurrence <strong>of</strong> Fusarium species and<br />

mycotoxins?<br />

S. Vogelgsang, I. Bänziger, T. D. Bucheli, F. E. Wettstein, H. R. Forrer<br />

Agroscope Reckenholz-Tänikon Research Station ART, 8046 Zurich, Switzerland<br />

E-mail: susanne.vogelgsang@art.admin.ch<br />

Throughout four years, wheat samples and information on cropping measures<br />

were collected from Swiss growers. Wheat grains were examined for incidence <strong>of</strong><br />

various Fusarium head blight (FHB) causing species, DNA amount <strong>of</strong> F.<br />

graminearum (FG) and content <strong>of</strong> different mycotoxins. In a total <strong>of</strong> 527 samples<br />

from 16 cantons, three Fusarium species were dominant: FG (64%), followed by<br />

F. poae (19%) and F. avenaceum (10%). The mean content <strong>of</strong> deoxynivalenol<br />

(DON) was 650 ppb and 12% <strong>of</strong> all samples were above the European limit for<br />

unprocessed cereals (1’250 ppb). The mean DON content varied between 260<br />

ppb in 2009 and 970 ppb in 2008. There was a significant positive correlation<br />

between FG incidence and DON content (r 2 =0.52) and between FG DNA quantity<br />

and DON content (r 2 =0.64).<br />

The combination <strong>of</strong> pre-crop maize and conservation tillage versus ploughing<br />

resulted in an average DON content <strong>of</strong> 2’200 ppb or 370 ppb, respectively. The<br />

use <strong>of</strong> other pre-crops further reduced the average DON content to 240 ppb. In<br />

samples from the two cropping systems wheat after maize with or without<br />

ploughing, zearalenone and nivalenol (NIV) contents were lower but showed a<br />

similar pattern as that DON, with means <strong>of</strong> 208 and 17 ppb for ZEA and to 27<br />

and 16 ppb for NIV, respectively. No significant correlation was found between F.<br />

poae incidence and the NIV content. One reason may be the presence <strong>of</strong> F.<br />

graminearum NIV chemotypes in Switzerland.<br />

Currently, DNA quantities <strong>of</strong> F. poae as well as the ratio <strong>of</strong> FG chemotypes are<br />

investigated by PCR analyses. The resulting data combined with in-depth<br />

multivariate analysis <strong>of</strong> various cropping measures will provide a better<br />

understanding <strong>of</strong> the relationship between fungal prevalence and toxin content.<br />

This knowledge is crucial to develop sustainable cropping systems with low risks<br />

<strong>of</strong> Fusarium occurrence and contamination <strong>of</strong> wheat.<br />

Keywords: cropping, Fusarium head blight, monitoring, wheat<br />

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