INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

RADISH (Raphanus sativus) with GROUP B/2 resistance: (INHIBITION OF ACETOLACTATE SYNTHASE ) Inhibition of Acetolactate Synthase

MUTATION: TRYPTOPHAN 574 to LEUCINE

Radish (Raphanus sativus) is a dicot plant in the brassicaceae family. A single amino acid substitution from Tryptophan 574 to Leucine has led to resistance to Inhibition of Acetolactate Synthase as indicated in the table below.		Radish

Chemical Family	Example Herbicide	Resistance Level
Imidazolinones	Imazethapyr	Resistant > 10 fold
Pyrimidinyl benzoates	Bispyribac-Na	Resistant > 10 fold
Sulfonylureas	Chlorsulfuron	Resistant > 10 fold
Triazolopyrimidine - Type 1	Chloransulam-methyl	Resistant > 10 fold
Triazolinones	Flucarbazone-Na	Resistant > 10 fold

NOTE

Although resistance was observed across the five chemical families, the magnitude of resistance was not determined for many of the herbicides (i.e., resistance may or may not be >10x for each family).

REFERENCES

Pandolfo, C. E., A. Presotto, F. Moreno, I. Dossou, J. P. Migasso, E. Sakima, and M. Cantamutto. 2016. Broad resistance to acetohydroxyacid-synthase-inhibiting herbicides in feral radish (Raphanus sativus L.) populations from Argentina.. Pest Management Science 72 : 354 - 361.

BACKGROUND

Soon after the commercial release of sunflower cultivars resistant to imidazolinone herbicides, several uncontrolled feral radish (Raphanus sativus L.) populations were found in south-eastern Buenos Aires, Argentina. These populations were studied in field, glasshouse and laboratory experiments aiming to characterise their resistance profile and to develop management tools.

RESULTS

Three feral radish accessions were highly resistant to ten active ingredients of five families of acetohydroxyacid synthase (AHAS)-inhibiting herbicides. Sequence analysis of the AHAS gene detected a Trp574Leu mutation in all resistant accessions. One accession with an intermediate level of resistance was heterozygous for this mutation, probably owing to gene exchange with a susceptible subpopulation located in the field margin. Herbicide-resistant and herbicide-susceptible radish could be controlled in sunflower by alternative herbicides.

CONCLUSION

This is the first report of feral radish with resistance to herbicides belonging to all the AHAS-inhibiting herbicide families, conferred by Trp574Leu mutation in the AHAS gene. An appropriate herbicide rotation with alternative herbicides such as fluorochloridone or aclonifen and an increase in the diversity of cropping systems are important for minimising the prevalence of these biotypes. © 2015 Society of Chemical Industry

This case was entered by Patrick Tranel Email: tranel@illinois.edu

Heap, I. The International Herbicide-Resistant Weed Database. Online. Wednesday, September 23, 2026. Available at www.weedscience.org

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