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.


Lessons learnt: crop-seed cleaning reduces weed-seed contamination in Western Australian grain samples

In this work AHRI researcher Dr. Mechelle Owen surveyed and quantified weed seed infestation of the crop seed that farmers would be planting. In Australia, farmers save their own crop seed (wheat, barley, pulse crops, non-hyrbid canola) for planting in the subsequent growing season. Farmers produce their saved crop seed on low weed burden crop fields, so as to minimise weed seed contamination. This survey was done in 2015. This is the third AHRI survey, with the first conducted in 1998 (Powles & Cawthray 1999) and a larger second survey in 2009 (Michael, Owen & Powles 2010). In this third survey in 2015, Mechelle Owen surveyed 81 crop seed samples, each of 10 kg crop seed (wheat, barley, canola, lupins).

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Plasma membrane receptor-like kinases and transporters are associated with 2,4-D resistance in wild radish

Resistance to the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) in wild radish (Raphanus raphanistrum) appears to be due to a complex, multifaceted mechanism possibly involving enhanced constitutive plant defence and alterations in auxin signalling. Based on a previous gene expression analysis highlighting the plasma membrane as being important for 2,4-D resistance, this study aimed to identify the components of the leaf plasma membrane proteome that contribute to resistance. Key results included: two receptor-like kinases of unknown function (L-type lectin domain-containing receptor kinase IV.1-like and At1g51820-like) and the ATP-binding cassette transporter ABCB19, an auxin efflux transporter, were identified as being associated with auxinic herbicide resistance.

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Metribuzin resistance via enhanced metabolism in a multiple herbicide resistant Lolium rigidum population

Most Australian crop farm populations of the grass weed Lolium rigidum are multiple herbicide-resistant. Most resistant populations exhibit target site mutations (e.g. ACCase, ALS), as well as metabolic resistance due to cytochrome P450, catalysed enhanced rates of herbicide metabolism.  

Interestingly, for the PS2 herbicides, target site mutations (psbA gene) are rare in these multiple resistant Lolium populations. Previously, we have documented metabolic resistance endowing resistance to PS2 triazine and urea herbicides. In this paper, paper Ma et al show that resistance to the triazinone herbicide metribuzin in a multiple resistant population is again not target site based but rather, it is metabolic resistance. Resistance is endowed by enhanced rates of metribuzin metabolism, likely P450 catalysed.

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