From Tomatoes to Wheat? OSU Researchers Help Farmers
by Katie Stacy

Water, water everywhere. Chances are, if you live in Oklahoma, this is not a phrase you have heard lately.

While the Sooner State has its advantages, it also has some areas that leave its residents "out to dry."

One of these circumstances is the weather. Oklahomans know putting away seasonal clothes is not wise with the way temperatures regularly go from 90 to 50 degrees in a day; however, it is something the devoted residents accept.

But what about Oklahomans who make their living from farming? What do you do when there is no rain for six months at a time?

"If you don't have moisture, you don't have growth," said Mike Bomhoff, a farmer and rancher from Okarche, Okla. "It takes a lot of moisture to grow forage."

Thanks in part to researchers at Oklahoma State University, farmers like Bomhoff might not have to worry about this problem quite so much.

Bjorn Martin, professor and researcher of plant and soil sciences at OSU, and Charles Tauer, professor and researcher at OSU, along with a post-doctoral researcher and several OSU students work on this project. They are members of a consortium funded by the National Science Foundation with Cornell University, the University of North Carolina and the Boyce Thompson Institute to better understand, and potentially increase, water-use efficiency in plants.

"Water is the most limiting resource for growth," Martin said. "Some plants can produce lots with little water while others cannot."

The project was developed because of the realization of water-use efficiency in wild plants. Researchers study domestic and wild breeds of certain plants to try to pinpoint drought resistance to transfer it to domesticated plants.

According to Cornell University, reduction in crop yield due to water stress is estimated at 65 percent globally; up to 80 percent of stream and river flow is already diverted to human use in many semi-arid regions.

As reported on the project Web site, the consortium will use a stable isotope technique to screen genotypes of modern crops and their wild relatives to identify differences in water-use efficiency.

A measure of naturally occurring, non-radioactive stable carbon isotope composition, known to be associated with plant water-use efficiency, will be used to perform a broad analysis of genetic factors that condition water-use efficiency in plants.

This will be followed by molecular techniques of fine mapping and marker-assisted selection to pinpoint the location of important genetic loci.

OSU researchers are applying their knowledge to tomatoes and Cornell is working with rice. Martin has worked with wild tomatoes since 1985 and was asked to be part of the project because of his expertise in the tomato area.

"We have evaluated 50 lines containing fragments of wild tomato chromosomes for water-use efficiency and have found one line that seems to be especially drought resistant," Martin said. "We have separated this line out and are trying to find the one gene within the line that carries the drought-resistant trait."

Martin and Tauer, along with OSU post-doctoral research associates Xiangyang Xu and Jun Yang, hope to identify which specific gene or genes are responsible for water-use efficiency. They then will be able to clone it to put into other species to make them more water-stress resistant.

It is difficult to say how long this research will take, but Martin estimates it will take another five to 10 years; Martin said it is still much easier than to attempt it by traditional breeding methods.

"Breeders have not been able to breed for water-use efficiency because it is so difficult to identify water-use efficient plants from those that are not," Martin said.

Martin said they hope to transfer what they learn about drought resistance in tomatoes to wheat. With wheat being Oklahoma's largest agricultural commodity, Oklahoma farmers have much to gain from this.

Martin said the knowledge learned from tomatoes will be useful in wheat. He said although wheat is hexaploid, a tomato is diploid, which makes it easier to analyze.

Martin said researchers should be able to pinpoint the drought-resistant gene more quickly with tomatoes than working directly with wheat.

"All genes are similar on a molecular level, and knowledge is transferable," Tauer said. "Anything learned from one plant can be used for another. With tomatoes, we can learn so many things rapidly.

"This knowledge can be transferred back."

So, why would a successful outcome be beneficial for Oklahoma's farmers? The recent drought is probably more than enough to answer that question for many people.

"Not having enough water at the right time is the No. 1 yield problem in Oklahoma," said Jeff Edwards, OSU small grains specialist. "While many times we may get enough total rainfall throughout the year, it arrives very sporadically. This is not good for plant survival."

Tauer said he hopes this research will help reduce the need for irrigation. As someone who relies on his wheat pasture to help feed his cattle, Bomhoff said he hopes these researchers are correct.

"The wheat that I planted in September is still green, and I am able to run cattle on it, but anything planted after that has not done well," Bomhoff said.

Bomhoff is certainly not alone in this. Many farmers and ranchers across Oklahoma have experienced the same problems.

"The bulk of wheat is dual purpose," said Case Medlin, extension weed specialist. "Less wheat also means less forage for cattle."

With all of the implications the recent drought has shown Oklahoma's farmers and ranchers, OSU's water-use efficiency research has become much more important to farmers.

"With technology comes great promises, but advances are a slow process," Edwards said. "If they are successful, this could be feasible for farmers to use, but it will take a number of years to implement it."

This will not just have positive results for Oklahoma agriculture. The seed will not only be delivered to OSU breeders for distribution but also likely will go to major national breeders, as well.

Because of the complexity of wheat's infrastructure, it will take time to implement what is learned from the studies. But to many, it will be worth the wait. If researchers are able to create more drought-resistant wheat, Oklahoma's farmers and ranchers will be able to say fewer prayers for rain.

For more information on the progress of the water-use efficiency project, visit http:// isotope.bti.cornell.edu.