Arkansas weed control: Why outcrossing is matter of concern

I ran into one of my good farmer friends in a café at lunch and commented that I was going to take off on a hunting trip. He said he thought it would be a good break for me because I had been “grouchy” in my articles lately. I sure never mean to be grouchy and will try to do better. However, some issues must be dealt with more directly than others.

As I have said in a couple of recent articles, I want to do everything I can from an education standpoint to help preserve the new Clearfield rice technology. I am sure I have sounded somewhat negative in a couple of these articles. I wish I could just write a really cheerful article and say, “Folks, the outcrossing issue with this technology is simply not a problem.”

Some have said I am making too big a deal about the plots of Tomilea Dillon, a University of Arkansas graduate student, because they represent “only the worse case scenario.”

My response to that is that I see a lot of grower fields with a red rice population equal to that in her research plots. Those are going to be the fields into which the technology will be placed first.

Some also say, “If you get red rice control, outcrossing won't be a problem.” This is true and one of the objectives of our educational efforts will be to help you get 100 percent red rice control.

Some have also told me that if I don't quit writing about outcrossing, I may kill the technology before it ever gets off the ground. That certainly is not my objective. In fact, my objective is just the opposite. I hope that every single farmer who plants Clearfield rice for red rice control goes into the program knowing not only that outcrossing can occur but that it will occur if the technology isn't properly used.

I believe that if every grower goes in fully aware, then we have a chance to make the technology last until we get some other herbicide-tolerant rice technology to help it out.

On the other hand, if too many people go in unaware, the technology will be useless in some fields as quickly as two years.

I wish every rice grower had been on the recent rice field day to get a visual picture of Tomilea's plots. Last week I said her estimated outcrossing rate was around 0.03 percent. I originally said an outcrossing rate this low should not be a problem. I have seen some preliminary models that indicate this would never become a problem.

In reality though, when you see what 0.03 percent surviving plants out of a heavy, emerged red rice population looks like on a per acre basis, it is very sobering. The farmer who had a total failure with his Clearfield rice program this year, had simultaneous flowering of the Clearfield rice and red rice, and planted Clearfield rice back into the same field next year has essentially blown the technology in that field.

I will provide a little more insight into these studies in a later article.

Ford Baldwin is an Arkansas Extension weed scientist. e-mail: [email protected]

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