You've heard about herbicide-resistant weeds (which farmers
hate) and herbicide-resistant crops like Roundup Ready soybeans
or corn (which farmers like). But here's a case — the only one I
know of — in which a weed helped create a herbicide-resistant
crop. The story begins in 1996, in a soybean field in Kansas.
The soybeans in this field were able to tolerate a class of
weedkillers known as "ALS inhibitors." This line of soybeans had
been created through "mutation breeding." This technique
involves exposing thousands of seeds to chemicals that cause
genetic mutations. One of those mutations allowed the resulting
soybean plant to withstand the herbicides. (Similar kinds of
herbicide-tolerant wheat, rice, and other crops have been
created using the same method.) Among the soybeans in this
Kansas field, however, a few weeds also survived after the
farmers sprayed their herbicide. The weeds were native
sunflowers, wild relatives of the sunflowers that farmers grow
as a crop. (As I reported a few months ago, sunfl