Australian Herbicide Resistance Initiative (AHRI)


Working in a number of research areas, AHRI has produced a large number of publications which are available to download. View the latest publications below, or search with the filter.


Influence of Crop Competition and Harvest Weed Seed Control on Rigid Ryegrass (Lolium rigidum) Seed Retention Height in Wheat Crop Canopies

In this paper, Walsh et al at several sites confirmed that the majority of retained Lolium seed at grain harvest will be captured. This was true in crop fields in which HWSC had been conducted for several years. 

Please note that we are NOT stating that plants cannot evolve resistance to HWSC. Indeed, everything that herbicide resistance has taught us is that plant populations will respond to any persistent, effective selection pressure. Importantly, this study showed that a good, competitive wheat crop meant that Lolium responded with taller plants, meaning that retained weed seed was relatively high in the canopy and thus captured by HWSC.  This shows the yield and weed control advantages of having a good, competitive high yielding crop. A healthy, competitive crop, HWSC and diversity in methods of weed control are key to sustainable systems!

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2,4-D and dicamba resistance mechanisms in wild radish: subtle, complex and population specific?

An overall finding of this study of auxinic herbicide resistance, at least in Raphanus R populations, is that conclusions on mechanisms cannot be made from studying just a few R populations. There are very clear differences between and within resistant populations. This research is ongoing in an attempt to reveal the important mechanisms that can endow resistance to 2,4-D and dicamba in plants.

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Glyphosate Resistance in Tridax procumbens via a Novel EPSPS Thr- 102-Ser Substitution

In this research, it was first established that Tridax, a global tropical weed species, evolved glyphosate resistance in the Ord River irrigation area in north-western Western Australia. This is the first report of glyphosate resistance in Tridax. The mechanism of glyphosate resistance was studied.  Various possible resistance mechanisms were NOT responsible for resistance (EPSPS gene amplification, different glyphosate uptake or translocation). In this glyphosate-resistant Tridax population, the glyphosate resistance mechanism is a mutation in the EPSPS gene causing substitution at amino acid 102 (Thr-102-Ser). 

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