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Australian Herbicide Resistance Initiative (AHRI)

Glyphosate resistant brome – gene amplification

Tag Archives | evolution

Australian Herbicide Resistance Initiative (AHRI)

Glyphosate resistant brome – gene amplification

Two years ago, a meeting was held in Australia to gather researchers who study weed, pest and disease resistance to see what they could learn from each other. There was a mind-blowing moment when an entomologist realised that the P450 enzymes he had been studying that gave resistance to an insecticide were the same as those that a weed researcher was studying that caused resistance to a herbicide (well… we thought it was mind-blowing. But then again, we’re weeds geeks!). Some new research by Jenna Malone, Chris Preston and others from the University of Adelaide weed research team have found…

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Australian Herbicide Resistance Initiative (AHRI)

27% achieved it. Can you?

Cricketer Glen McGrath was a specialist bowler, but he couldn’t bat to save himself. NFL punter Steve O’Neil was a specialist kicker. He once punted the ball a record 98 yards, but could he throw? It turns out that seed cleaners are specialists at cleaning seed. Go figure! Research by Pippa Michael (now Curtin) and AHRI researcher Mechelle Owen from 2008 showed that 73% of cleaned crop seed samples had some level of weed seed contamination. The most common weed species found were ryegrass, wild radish, brome grass and wild oat. The kicker? Many of these populations were also herbicide resistant!…

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Australian Herbicide Resistance Initiative (AHRI)

Early flowering wild radish paradox

If you drop a piece of toast, it will land butter side down (the likelihood of this is proportional to the price of the carpet). If you drop a cat, it always lands on its feet. But if you strap a piece of toast to the back of a cat, butter side up, and drop the cat, now that is a paradox. If we adopt harvest weed seed control to get on top of the wild radish seed bank, could we paradoxically select for early flowering and early shedding wild radish that can avoid harvest weed seed control, and create…

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Australian Herbicide Resistance Initiative (AHRI)

How to beat unfit weeds

How good would it be to turn up to play a game of football or hockey (or whatever your sport) against a team that you know is 30% less fit than your team? It’s a walk up start. As you watch them eat their pre-game pie and smoke their pre-game cigarette, you know that the odds are stacked in your favour.     AHRI researchers recently discovered that some resistant weeds are not very fit. In fact, in this case, the most resistant weeds are the least fit. The 1781 mutation in ryegrass causes moderate clethodim resistance, and high level ‘fop’…

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Australian Herbicide Resistance Initiative (AHRI)

Wild oat – always the bridesmaid

Wild oat is the Yohan Blake of weeds. Yohan is an amazing sprinter, but unfortunately for him, his Jamaican training partner Usain Bolt is faster. Wild oat is a significant resistant weed, but it’s no annual ryegrass. AHRI researcher, Dr Roberto Busi recently showed that repeated use of low doses of Hoegrass® caused only a minor (2 fold) shift towards resistance in wild oat. When Dr Paul Neve did a similar study in 2005, three low doses of Hoegrass® caused 40 fold resistance in annual ryegrass. Annual ryegrass is the world champ of herbicide resistance, and while weeds such as…

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Australian Herbicide Resistance Initiative (AHRI)

Simazine resistant silver grass

When Airbus delivered the first A380 aircraft in 2008 they were very proud of the fact that it was the quietest commercial airliner ever produced. The unintended consequence of this, however, was that it led to a worse experience for passengers as more unpleasant noises (e.g. crying babies, snoring passengers, flushing toilets) were elevated in the quieter cabin. Back to the drawing board! They actually engineered some sound back into the cabin by piping in ambient noise. When ConsultAg agronomist Garren Knell tackled a high ryegrass seedbank with one of his clients in southwest Western Australia 12 years ago, they…

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Paul Neve in lab

Australian Herbicide Resistance Initiative (AHRI)

Knock knock

Knock knock Who’s there? Little old lady Little old lady who? I didn’t know you could yodel! It is double knock season in Australia. Glyphosate resistance has been confirmed in many fields across the country in at least 10 weed species. Public enemy number one is the world champion of herbicide resistance, annual ryegrass. Glyphosate resistant ryegrass has been confirmed in hundreds of fields in Australia and is suspected in thousands. The double knock technique of glyphosate followed by paraquat is a very useful tool…when done right. The right sequence – glyphosate followed by paraquat; the right timing – anywhere…

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Australian Herbicide Resistance Initiative (AHRI)

Chicken or the egg?

It is one of the great philosophical discussions – what came first, the chicken or the egg? (Spoiler alert – the egg came first). What came first, herbicides or herbicide resistance?  We have always assumed that weeds have random genetic mutations that occur naturally in a population. That herbicides merely select for these mutations by killing all of the other plants in the population, leaving behind the resistant plants. However, we had no evidence. Until now. French researcher Christophe Delye and others from INRA in Dijon, France set out to answer this question once and for all. They studied herbarium…

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Australian Herbicide Resistance Initiative (AHRI)

Nature mimics science

The Wright brothers spent a lot of time observing the curved shape of bird’s wings and how air flowing over this curved shape caused lift. This is one of the great examples of science mimicking nature. Does nature ever mimic science? One of the first glyphosate tolerant crops was GA21 Corn. This corn cultivar was created by molecular biologists in the lab. It contained the so called TIPS mutation which gave it glyphosate tolerance. The TIPS mutation had never been observed in nature until recently when AHRI PhD scholar, Adam Jalaludin, and AHRI researcher Dr Qin Yu, discovered it in…

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Plants in pots

Australian Herbicide Resistance Initiative (AHRI)

How fit are you?

Within the AHRI research team we have a range of fitness levels. At one end of the scale we have Dr Roberto Busi, winner of the Perth marathon for two years running. Further down the scale we have Professor Stephen Powles who recently put his back out watching the World Cup final on television! Resistant weeds also have a range of fitness levels. In some cases, the resistance mechanism weakens the plant and it doesn’t grow quite as well as it once did. In other cases, the resistant plants are just as fit as their susceptible counterparts. Palmer amaranth in…

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