Scotty Smothers, senior research associate at the Fisher Delta Research Center in Portageville, Mo., has been advancing flood-tolerant soybean lines for 15 years in a multi-state research project funded by the Missouri Soybean Merchandising Council and the Mid-South Soybean Board. Working collaboratively with Dr. Pengyin Chen, Dr. Grover Shannon, and Dr. Ollie Liakat, the long-range goal has been to create a soybean variety that delivers both high yields and a tolerance for flooding that will allow farmers, even in extremely wet growing seasons, to make a profit on soybeans.
Some of the genetic material he and the other breeders are using to transfer those flood-tolerant traits into high-yielding varieties comes from wild exotic germplasm from Asian countries. “The downfall of using those wild accessions is the lack of yield potential they carry,” says Smothers. “What we have found however, is when we take that first-generation flood-tolerant line and cross it into a non-flood-tolerant line, we can get a 10- to 15-bushel yield increase. When we then advance that to the next generation, we get another 10- to 15-bushel yield increase. The problem is, this process takes time.”
At the beginning of this year’s growing season, Smothers planted the most recently developed lines, and at R-1, or flowering, and then induced a continuous flood for 10 days straight. He is now looking at the “phenotypic” or visual differences in those 382 plants and will move forward the most promising lines.
“In our first year, we planted every type of soybean we thought could contribute any genetic aspect of flood tolerance on a zero-grade field and kept it flooded under 2 inches of water until the plants started turning yellow and dying,” says Smothers. “We quickly found out there are no soybean lines that will grow in a rice environment, but there are some lines that will respond ‘less negatively’ and that was key.”
Genetic maps, variety trials
He and the other breeders then began making genetic population maps to pinpoint where those genes were originating. The team kept seeing more flood-tolerant characteristics coming from those wild exotic soybean lines. Despite their less-than-healthy look, they exhibited less water stress in that flooded environment.
“Then we took those plants with those flood-tolerant characteristics and bred them back to elite high-yielding soybean germplasm or germplasm showing other aspects of flood tolerance,” says Smothers. “It’s a very tedious process because we only expect to forward 10 of the 382 plants.”
The breeders are placing any soybean line being considered for release in multi-location variety trials under the same soil type and under normal conditions. All varieties included in the official Missouri State Variety Tests will be screened for flood tolerance as well. “The soybeans producers plant on their farming operations will more than likely have some level of flood tolerance screening in its genetic lineage,” says Smothers.
The official Missouri State Variety Trial publication will be released toward the end of this year. “Some of those varieties in the trial may even have consecutive years of data so you can compare them and see where one line may have performed well for multiple years in a row. That’s the line I would recommend trying on poorly draining field,” concludes Smothers.
Smothers hopes to have soybean varieties with improved flood tolerance ready for consideration for commercial release within the next two to four years.