In times of weed resistance, you might wonder what could make you say ‘thanks’ to one. Improved yield and resistance to soybean cyst nematode and soybean rust may quickly convince you to be grateful for at least one weed.
More than 12 years of hard work have led to this moment. Ram Singh, research geneticist with the USDA Agricultural Research Service (ARS) at the University of Illinois, has successfully crossed soybean Dwight variety with Australian perennial weed Glycine tomentella. This could lead to greater yield potential and protection from common problems.
“Nobody else in the world has done this research,” Singh says. “I started in 2002.”
This difficult research is one-of-a-kind. Crossing soybeans with G. tomentella presented a variety of challenges. Perhaps the most challenging was when Singh discovered the plants he created were sterile.
Soybeans have 40 chromosomes and G. tomentella have 78. Hybrid plants with chromosomes from both parents contain 59 chromosomes and that causes them to be sterile, Singh explains.
“Subsequent backcrossing to Dwight produced 40-chromosome soybean plants after six years,” Singh says.
After Singh created the 40 chromosome plant his research could advance, but with new discovery comes new challenges. Singh had to find a way to preserve pods and seeds.
“Not all seeds germinate; some die,” Singh says. And in research, a dead seed could kill years of hard work.
Singh found a method to create multiple plants from one seed—taking the error out of trial and error. Singh used growth hormone mixtures that help hybrid pod retention. He dissected the immature seeds and developed cultures to create multiple plants.
“If a plant dies, you don’t have a total loss,” Singh says. This method sped up his research and allowed for faster field testing.
“The first plants were in the field in 2008,” says Randall Nelson, research geneticists with USDA ARS and professor of plant genetics at the University of Illinois.
Nelson, who works closely with Singh, led in-field research for the new soybean lines. The team started field testing seven years ago with 200 lines and continues today.
“A lot of unexpected things are happening when we make these wide crosses,” Nelson says. “Lines are very high yielding relative to the parent.”
The parent, Dwight, is a soybean variety more than 20 years old. In-field tests show the experimental soybean is out yielding Dwight by 4 to 7 bu. per acre.
“We have something from G. tomentella that is increasing yields,” Nelson says.
A weed increasing yields might sound far-fetched, but Nelson and Singh have research that shows it could be the case. The cross provides a yield boost and resistance to Soybean Rust, Phytophthora and Soybean Cyst Nematode. The resistances protect the plant and its increased yield potential.
However, these varieties won’t be hitting shelves quite yet.
“It will be at least 5 to 10 years before there are commercial varieties,” Nelson says. “There are several soybean breeders crossing these lines with the best varieties this summer. The test will be if we can obtain similar yield increases over these very good varieties that we were able to get over Dwight.”
Research over the next 5 to 10 years will also provide more research into what is actually causing the yield increase.
“We don’t know anything about the yield genes,” Nelson says.
This research will show if yield increases in these lines are coming from areas in the genetic code previously shown to increase yield or if they have discovered a new area coming from G. tomentella.
Ultimately, Nelson and Singh both want to see this in the hands of farmers.
“I am excited to see when farmers will harvest this hard work. Sooner is better than later,” Singh says.