Here's a figure I'm showing students in my weed science class today. It is a slightly modified version of the figure I published in this paper: www.cambridge.org/core/journal... - ThreadSky

wyoweeds.bsky.social • 110 days ago

Here's a figure I'm showing students in my weed science class today. It is a slightly modified version of the figure I published in this paper: https://www.cambridge.org/core/journals/weed-science/article/genetically-engineered-herbicideresistant-crops-and-herbicideresistant-weed-evolution-in-the-united-states/22B3B07F8EB980D2CFEEE3AA36B7B2C1

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wyoweeds.bsky.social•110 days ago

In a nutshell, the figure shows that there are some herbicides (like Group 15 herbicides that inhibit very long chain fatty acid synthesis) that have been used a LOT, but few weeds have evolved resistance. But there other herbicides have MANY resistance cases even if used less often.

wyoweeds.bsky.social•110 days ago

Not all herbicides are the same! If you're worried about 'superweeds' evolving resistance to herbicides, then you should probably also worry about the *types* of herbicides being used. The details really matter, but are rarely acknowledged when this topic is discussed.

cheryl162.bsky.social•110 days ago

I wonder what is about Group 7 herbicides that make resistance so possible??

wyoweeds.bsky.social•110 days ago

In the last 5 years (shortly after I published the paper) that group was merged into Group 5. So the current placement of Group 7is probably too high.

wyoweeds.bsky.social•110 days ago

But similar questions could be asked of Groups 1 and 2,and the answers are pretty interesting (though probably too complex for a short answer here).

genomeric.bsky.social•95 days ago

From my perspective, it is clear that at least for group 1 and group 2, there are just too many simple point mutations that cause resistance without drastic fitness penalties. These mutations are at a high rate in the unselected population because the alleles aren't purged by natural selection.

wyoweeds.bsky.social•95 days ago

Yes, that's the general explanation I use in the class.

genomeric.bsky.social•95 days ago

Folks have found group 1 resistance mutations in black grass herbarium samples from the eighteen hundreds.... And it's not like they had to do ten thousand plants to find it

wyoweeds.bsky.social•95 days ago

I love this example, and also present that in class. I even wrote a blog post about the herbarium study years ago! https://plantoutofplace.com/2016/07/herbicide-resistance-predates-herbicides-by-over-80-years/

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