Baisakh’s lab is also using molecular markers to map tolerance to the widely used herbicide Sencor. Some varieties of wheat are susceptible to the herbicide and can be killed along with the weeds.

“Growers like to use Sencor soon after planting,” Harrison said. “It is effective and inexpensive and gives broad spectrum wheat control.”

In this project Harrison crossed two varieties — one resistant to Sencor and one highly sensitive to it. He developed about 200 progeny and screened them over several field locations. Harrison said the wheat was sprayed with a high rate of Sencor — around twice the normal rate.

The researcher and his graduate student took notes on which lines showed tolerance and which were damaged.

“Now we will go and do molecular work to find a segment of DNA that contains the gene that gives you tolerance to Sencor,” he said.

Weed scientists have done screening for Sencor tolerance, but Harrison said it involves a lot of resources to screen many varieties in several environments over several rates of Sencor and is usually only done every few years.

“We have new varieties every year. But with molecular markers, you could tell in a week whether a new variety contains the gene for tolerance to Sencor,” Harrison said.