Scientist works to increase crops' water saving potential

April 18, 2018, University of Tennessee at Knoxville
Soybeans under a rainout shelter at the University of Tennessee's West Tennessee AgResearch and Education Center. These shelters are used to simulate drought conditions as scientists work to identify crops with water saving potential. Both soybeans and cotton are being evaluated. Credit: Ginger Rowsey

There is one ingredient that every single crop is absolutely dependent on—water.

Producers have implemented irrigation and fine-tuned cultural practices to make the most of available moisture, but soil conditions and unpredictable rainfall can still make crops vulnerable to yield-reducing drought.

Plants also lose gallons of daily through transpiration. Transpiration, or the loss of water through plant tissue, accounts for more than 98 percent of water taken up by .

"Identifying plant physiological traits that minimize the impact of drought appears to be the best bet for increasing yields under water deficit conditions," says Avat Shekoofa, assistant professor with the University of Tennessee Department of Plant Sciences. "One trait that shows great potential for conserving water among row crops is limited transpiration under high atmospheric vapor pressure deficit."

Vapor pressure deficit (VPD) is the difference between the water vapor pressure inside the leaf and the water vapor pressure of the air at a certain temperature. Under high VPD conditions, which typically occur in the middle of the day, water transpires through , specifically stomata. However, crops that exhibit the limited-transpiration trait will restrict transpiration during high VPD conditions by partially closing their stomata, thus conserving soil water levels for later use.

"When the stomata partially close, instead of losing water through transpiration, those plants are able to save that water for later in the season and can sustain productivity through the grain fill stage," says Shekoofa.

Conserving water while sustaining crop yields is not just a farmer concern—it's a humanity concern. With a growing world population and finite land and water resources, identifying crops with water saving potential could be a central issue for the future of food and water security.

Shekoofa has studied the response of transpiration rate with increasing VPD in several crop species, including soybean, corn, sorghum and peanut. In a 2017 study at the West Tennessee AgResearch and Education Center, she tested six cotton cultivars for the expression of the limited transpiration trait and observed it in one (Phytogen 490 W3FE). This is the first time this trait has been observed in a commercially available cotton variety in the Mid-South.

"More than 92 percent of cotton production in my state of Tennessee is dryland, and producers have few options to mitigate drought stress," says Shekoofa, who presented these findings at the 2018 Beltwide Cotton Conference. "As with any crop, identifying a variety that exhibits high water saving potential will be helpful to producers who are looking to sustain production through future droughts. For example, one demonstrated advantage of DuPont Pioneer's AQUAmax maize hybrids is their expression of the limited-transpiration trait."

While the limited transpiration trait has been identified in multiple , it is not widely available in commercial cultivars. Shekoofa says the next challenge is applying the trait in breeding programs. There are questions as to how readily it will be available to progeny lines, but according to a study co-authored by Shekoofa in the January issue of the Journal of Crop Improvement, there appears to be a strong possibility of transferring the limited transpiration trait to progeny.

"The results showed that with one parent exhibiting the limited transpiration trait, a reasonable percentage of progeny expressed a breakpoint that would achieve drought tolerance in the field. This is encouraging for future drought-tolerant crop research."

Shekoofa will continue her research with a focus on identifying limited transpiration traits in soybean and cotton varieties.

Explore further: Scientists engineer crops to conserve water, resist drought

Related Stories

Scientists engineer crops to conserve water, resist drought

March 6, 2018

Agriculture already monopolizes 90 percent of global freshwater—yet production still needs to dramatically increase to feed and fuel this century's growing population. For the first time, scientists have improved how a ...

Plant gene for water efficiency found

July 11, 2005

ANU researchers have identified a gene that regulates the water efficiency of plants, the first to be discovered that mediates the process critical to plant survival, crop yield and vegetation dynamics. Dr Josette Masle, ...

Groundwater flow is key for modeling the global water cycle

May 1, 2017

Plants are one of the largest water users on land and, through transpiration, they move more water into the atmosphere than streams or rivers move across the landscape. Unlike stream flow, which can be easily observed, measuring ...

A new transporter gene that regulates plant transpiration

September 9, 2011

When plants feel stress from a lack of water, they close their epidermal pores, or stomata, to prevent water loss via transpiration. Each stoma is flanked by a pair of guard cells, which change shape to close or open stomata ...

Winter wheat feasible cover crop for Rolling Plains cotton

November 28, 2017

Interest in using cover crops to improve soil health continues to grow in the Texas Rolling Plains region, but the nagging concern of reductions in soil moisture and effects on yields of subsequent cash crops still exists.

Recommended for you

Paris climate targets could be exceeded sooner than expected

September 17, 2018

A new study has for the first time comprehensively accounted for permafrost carbon release when estimating emission budgets for climate targets. The results show that the world might be closer to exceeding the budget for ...

More ships and more clouds mean cooling in the Arctic

September 17, 2018

With sea ice in the Arctic melting at an alarming rate, opportunities for trans-Arctic shipping are opening up, and by mid-century ships will be able to sail right over the North Pole—something not previously possible for ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.