Thriving with Wet Feet

Flooding

Researchers zeroing in on flood-tolerant varieties

It’s no secret that soybeans don’t often perform well in wet soil. Plants with “wet feet” for extended periods of time will turn yellow, suffer from reduced nitrogen fixation and rarely recover enough to reach full yield potential. With support from the soy checkoff, researchers at the University of Missouri (MU) Fisher Delta Research Center in southeast Missouri are getting closer to releasing varieties bred with increased flood tolerance.

MU soybean breeder Grover Shannon, Ph.D., says there are about 8 million acres in the Mississippi River Delta area alone with soybeans growing in slowly-drained soils. The soils are heavy and many fields have nearly zero grade.

A lot of farmers in the region irrigate, so drought can be taken out of the equation, but there’s not much farmers can do when there’s too much water.

Shannon says the germplasm base for flood tolerance is quite narrow. Working with about 19,000 specimens from around the world, MU researchers have found and mapped genes for flood tolerance. Many of the most promising flood-tolerant varieties also showed resistance to Phytophthora, so it appears that resistance could be a key to breeding varieties with superior flood tolerance.

“We won’t get varieties that live in water, but we can develop ones that give farmers confidence that they won’t lose all their yield,” Shannon contends.

Shannon says under flood conditions, several progeny of the test lines yielded three times as much as the varieties currently available. While that’s encouraging, he says they’re still a year or more away from releasing a variety because the yield still isn’t where it needs to be.

“We can get tolerance, now we need the yield,” Shannon adds. “A farmer needs to be confident that what he plants is going to yield no matter where he puts it.”