Seed World

K-State Researchers Work to Develop Heat-tolerant Wheat

Harold Trick, a Kansas State University plant pathologist, and Allan Fritz, a KSU wheat breeder, are working on a transgenic wheat that tolerates warmer temperatures during wheat’s critical grain filling stage. With just a single added gene to boost thermo-tolerance, this wheat could increase yields by up to 35 percent.
Wheat has an optimum temperature range during the grain filling stage of 15 degrees to 18 degrees Celsius (59 to 64 degrees Fahrenheit). Trick explains that for every 1 degree Celsius rise in temperature above that level, 3 to 4 percent of yield could be lost.
As the grain begins to fill, it accumulates starch. This starch will account for 75 to 85 percent of the grain’s dry weight, making it an important part of farmer’s final test weight. That starch is converted from sucrose by the enzyme soluble starch synthase (SSS).
Trick and his team sought a way to increase the wheat plant’s tolerance to these higher than optimal temperatures. They started with rice, a tropical plant grown at higher temperatures that also has grain that fills. They found a single SSS gene that provides more thermo-tolerance when added into the genome. This gene shows the best yield increase at temperatures of 29.5 to 32.3 degrees Celsius (85.1 to 90.1 degrees Fahrenheit).
With patents filed for these traits, Trick and Fritz are now working to cross this thermo-tolerance into elite wheat varieties that have their own heat tolerance potential.
Because no genetically modified wheat is currently in the U.S. supply chain, this heat-tolerant wheat will eventually need a sponsor that can take it through the strenuous and extensive regulatory process before it can be commercialized and be planted by Kansas farmers.
“We want the technology in hand and validated so when GM wheat is allowed to be grown, the product is there for companies who see its value,” Trick says.
Their research is funded by Kansas wheat farmers.