Frances Gould, Blanchard, Tobie M. | 10/13/2016 7:00:19 PM
Staying ahead of diseases and guarding against herbicides are two projects in the LSU AgCenter wheat program.
Wheat breeder Steve Harrison is trying to improve wheat resistance to diseases such as stripe rust, bacterial streak and Fusarium head blight, which is commonly referred to as scab.
Harrison’s program released the variety AGS 3000 in 2015, and Harrison said it produced good yield results in this year’s trials.
“In a harvested test comparing varieties, AGS 3000 was in the top two or three for yield and had high test weight and low scab issues,” Harrison said.
Harrison is working with molecular biologist Niranjan Baisakh to use molecular markers — small fragments of DNA — to identify desirable genes in potential wheat varieties that would offer resistance to diseases and herbicides.
Baisakh said some varieties of wheat tolerate the nonselective herbicide Sencor, but other varieties don’t, and those plants can be killed along with weeds.
Baisakh uses a genetic mapping strategy to identify specific regions of the chromosome that control resistance to Sencor. From there, he can identify genes and linked DNA markers associated with resistance to Sencor.
Baisakh used the same method to identify genes for stripe rust resistance in the Louisiana wheat variety LA841.
“We found three regions in two chromosomes that control wheat stripe rust resistance,” Baisakh said, adding that the three markers work together. “When markers are present together, that is a positive indicator for resistance.”
In the field, plant pathologists Boyd Padgett and Trey Price evaluate variety trials in multiple locations across the state to determine how wheat varieties stand up to diseases. They also evaluate the effectiveness of fungicides on wheat disease management.
Padgett said some varieties exhibit good resistance to some diseases, so fungicide applications may not be necessary.
“You don’t take antibiotics when you are not sick,” Padgett said. “Using a fungicide only when necessary increases the fungicide’s longevity and promotes fungicide stewardship.”
Harrison said this past year was a good year for his program with some milestones, but he said it was frustrating in terms of breeding material.
“We lost a lot of material when the Mississippi River came up and saturated the soil at primary test sites,” he said.
The AgCenter’s wheat and oat breeding program is a member of SunGrains, a consortium of Southern universities’ wheat breeding programs.
“One good thing about SunGrains is that if one of us loses material, you can ask someone in another state to save seed of their material, so we help each other out,” Harrison said. Tobie Blanchard