Researchers To Eliminate Weeds By Stopping Reproduction

Researchers have discovered that waterhemp, and possibly other weeds don’t respond to rotating herbicides each year as they originally thought.

( Sonja Begemann )

It could be called a battle of the sexes. But in this war farmers (of both genders) could end up the victor. With a half-a-million dollar grant from USDA’s National Institute of Food and Agriculture, University of Illinois researchers are investigating genetic control of waterhemp and Palmer amaranth.

Since waterhemp and Palmer amaranth use sexual reproduction, requiring male and female plants, thinning populations to just males could drastically reduce the weed’s effect on farm fields.

In theory, researchers will change the ratio of male to female waterhemp and Palmer amaranth populations. Every mating will only produce male offspring, and in just a few generations every individual in the population will be male, ceasing reproduction.

“A genetic control strategy would be a way to introduce specific genetic controls that could change and ultimately eliminate the population,” says Pat Tranel, molecular weed scientist and interim head of the Department of Crop Sciences of University of Illinois.

This strategy is similar to one used in mosquitos to help reduce their populations and the spread of Zika. Researchers genetically modified the insect and released it into nature where they mated with native females and the resulting offspring all died. This method was used in Florida and select other countries.

There is much work left to be done before this strategy can be deployed against waterhemp and Palmer amaranth. Researchers need to find the genes responsible for gender in the weeds. Fortunately, they’ve already identified the part of the genome that allows females to produce non-viable male offspring. However, they have more research to do on that front as well before it can be inserted into the weeds.