<b>HRAC Group 5</b> <font size='2'> (Legacy C1 C2) </font> resistant Beckmannia syzigachne from China

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 5 (LEGACY C1 C2) RESISTANT AMERICAN SLOUGHGRASS
(Beckmannia syzigachne)

PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)

China

INTRODUCTION		AMERICAN SLOUGHGRASS
American Sloughgrass (Beckmannia syzigachne) is a monocot weed in the Poaceae family. In China this weed first evolved resistance to Group 5 (Legacy C1 C2) herbicides in 1993 and infests Cereals, and Wheat. Group 5 (Legacy C1 C2) herbicides are known as PSII inhibitors - Serine 264 Binders (Inhbition of Photosynthesis at PSll - Serine 264 Binders ). Research has shown that these particular biotypes are resistant to chlorotoluron and they may be cross-resistant to other Group 5 (Legacy C1 C2) herbicides. The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

QUIK STATS (last updated Jun 06, 2000 )
Common Name	American Sloughgrass
Species	Beckmannia syzigachne
Group	PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
Herbicides	chlorotoluron
Location	China
Year	1993
Situation(s)	Cereals, and Wheat
Contributors - (Alphabetically)	Heling Tu, and Tang-Hong Yuan
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Tang-Hong Yuan

Found in a suburb of Shanghai.

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GENERAL

Tang-Hong Yuan

Due to no crop rotation or cultivation, along with 20 years use of chlortoluron.

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ACADEMIC ASPECTS

Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible American Sloughgrass biotype with this American Sloughgrass biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.

Genetics

Genetic studies on HRAC Group 5 resistant American Sloughgrass have not been reported to the site. There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature

Mechanism of Resistance

The mechanism of resistance for this biotype is either unknown or has not been entered in the database. If you know anything about the mechanism of resistance for this biotype then please update the database.

Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes. If you have any information pertaining to the fitness of Group 5 (Legacy C1 C2) resistant American Sloughgrass from China please update the database.

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CONTRIBUTING WEED SCIENTISTS

HELING TU

Quinghai Academy Of Agricultural Science 464 Plant& Soil Sciences Building Xining, Qinghai China

TANG-HONG YUAN

Shanghai Academy Of Agricultural Sciences Plant Protection Institute 26 No555 Shanghai, Qinghai China Email Tang-Hong Yuan

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in China have been instrumental in providing you this information. Particular thanks is given to Heling Tu, and Tang-Hong Yuan for providing detailed information.

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Herbicide Resistant American Sloughgrass Globally
(Beckmannia syzigachne)

Country

FirstYear

Situation

Active Ingredients

Site of Action

China

1993

Cereals, and Wheat

chlorotoluron

PSII inhibitors - Serine 264 Binders ( HRAC Group 5 (Legacy C1 C2)

China

2010

Winter wheat

fenoxaprop-ethyl

Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)

Japan

2010

Spring Barley, and Wheat

trifluralin

Inhibition of Microtubule Assembly ( HRAC Group 3 (Legacy K1)

Literature about Similar Cases

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Li YiWei ; Chen YiFeng ; Li YongFeng ; Tang RiSheng ; Mei ChuanSheng. 1997. Inductive resistance to chlorsulfuron in Beckmannia syzigachne and Alopecurus japonicum in vitro. Jiangsu Journal of Agricultural Sciences 13 : 85 - 89.

In vitro experiments were conducted to study the characteristics of induced resistance to chlorsulfuron in subcultures of Beckmannia syzigachne and Alopecurus japonicum young-panicle callus tissue. Results indicated that the sensitivity of acetolactate synthase (ALS) decreased in both the weed species with increasing chlorsulfuron concentration. The IC₅₀ (the concentration causing 50% inhibition) of ALS activity increased from 1 to 300 µg/litre for 6-12 subcultures of B. syzigachne and from 1 to 100 µg for 4-10 subcultures of A. japonicum. Induced resistance was also observed in regenerated plantlets of B. syzigachne; resistant plantlets from subcultures exposed to high levels of chlorsulfuron suffered less inhibition of growth when exposed to 200 µg and fewer died when exposed to 1000 µg than did those regenerated from subcultures with a history of lower level chlorsulfuron exposure. Callus growth and differentiation, and plantlet development in B. syzigachne were unaffected by chlorsulfuron during subculturing..

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