EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 2: SECONDARY METABOLITES – BIOCHEMISTRY,<br />
BIOSYNTHESIS, FEED AND FOOD SAFETY<br />
P25 - Influence <strong>of</strong> pre-harvest moisture and harvest<br />
time on fusarium mycotoxin concentrations in winter<br />
wheat<br />
L. L. Kharbikar, E. T. Dickin, S. G. Edwards<br />
Harper Adams University, Newport, Shropshire, TF10 8NB, UK<br />
E-mail: llkharbikar@harper-adams.ac.uk<br />
Fusarium graminearum is the most devastating head blight pathogen and<br />
contaminates grain with the mycotoxins deoxynivalenol (DON) and zearalenone<br />
(ZON). Rainfall at anthesis is known to influence the infection and subsequent<br />
production <strong>of</strong> these mycotoxins in wheat but less is known <strong>of</strong> the impact <strong>of</strong> rainfall<br />
later in the growing season. In 2008 the UK suffered the highest recorded levels<br />
<strong>of</strong> DON and ZON and this was possibly related to the delayed wet harvest.<br />
Anecdotal evidence from end-users suggested that more grain deliveries at intake<br />
failed to meet legislative limits when harvested after rather than before the delays.<br />
The impact <strong>of</strong> pre-harvest moisture and harvest time on mycotoxin concentrations<br />
in winter wheat was studied in two controlled environments. After inoculation with<br />
isolates <strong>of</strong> F. graminearum at anthesis, plants were bagged for 96 h. At hard<br />
dough maturity ears were kept moist by watering for 2 minutes every hour for 8<br />
hours a day using a watering can and bagged overnight or left dry until harvest<br />
and harvested when ripe one week later (early harvest) and again a week later<br />
(late harvest). Ears were harvested, dried and then milled. Mycotoxin<br />
concentrations were determined using R-Biopharm ELISA kits. Low level <strong>of</strong> ZON<br />
in the first experiment suggested the water treatment was not sufficient to<br />
stimulate ZON production. Therefore, in a second experiment plants were mist<br />
irrigated for 2 hours every day and bagged overnight to retain the moisture after<br />
hard dough maturity until harvest. DON levels were very high as a result <strong>of</strong> the<br />
severe infection achieved within these experiments; however the impact <strong>of</strong> preharvest<br />
moisture and harvest date was greater for zearalenone. Results indicate<br />
that, late season moisture can significantly increase DON and ZON in wheat and<br />
early harvesting, if practical, is strongly advised to reduce the mycotoxin levels in<br />
wheat.<br />
Keywords: Pre-harvest rainfall, Fusarium graminearum, zearalenone, wheat<br />
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