NASA Helps Build Better Soybeans For A Hot, Dry, Hungry World



Published on 17 April 2014


by NASA

(WireNews+Co)

Washington, D.C.

A new study shows soybean plants can be redesigned to increase crop yields while requiring less water and helping to offset greenhouse gas warming, NASA announced April 15.

The study, the first to demonstrate a major food crop can be modified to meet multiple goals simultaneously, was led by Darren Drewry of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

Using an advanced vegetation model and high-performance computer optimization techniques, the study showed redesigning soybean plants in various ways makes it possible to increase soybean productivity by 7 percent without using more water.

Soybean plants also could be redesigned either to use 13 percent less water or to reflect 34 percent more light back to space without a loss of crop yield.

“My intuition would have told me that some of these goals are mutually exclusive — that there is a fundamental tradeoff between increasing productivity and conserving water,” said Drewry. “We are now able to say that there actually is a combination of traits that will make progress toward all of these goals simultaneously.” The study by Drewry and coauthors Praveen Kumar and Stephen Long (both of the University of Illinois) was published April 4 in the journal Global Change Biology.

The research, funded by the National Science Foundation with support from JPL and the Bill & Melinda Gates Foundation, comes at a time when global food security is threatened by population growth and climate change.

The United Nations estimates that food production will need to increase 70 percent by 2050 to meet the world’s food needs, but currently yields of major crops are increasing slowly or not at all. Soybeans are the world's most important protein crop.

MODIFIED CROP COVERS COULD MITIGATE CLIMATE CHANGE

Drewry developed the model he used for this study (called MLCan, for multi-layer canopy model) to study U.S. Midwest agricultural systems, but it can be modified for research on other types of vegetation. It captures exchanges of carbon dioxide, water and energy between vegetation and the atmosphere in great detail.

The research used numerical optimization, a mathematical way to decide which choice among a range of options will create the closest match to a desired outcome. Drewry chose five structural characteristics of a plant, such as the total leaf area (the number and size of the leaves) and the angle at which leaves are set on the plant stems. The MLCan model varied one or a combination of the five traits for each experiment, discarding less successful solutions and refining those that made progress toward the goals.

Depending on which goals they are intended to meet, redesigned soybean plants can differ significantly. One experiment in the study produced a plant that required 13 percent less water but was just as productive as current varieties. It would be valuable for farmers in drought-stricken areas. This plant had fewer leaves overall, and more of the leaves were located toward the bottom of the plant than is common among current varieties.

Reflecting more radiation back to space involves redesigning a number of traits, such as how much light leaves reflect in certain portions of the solar spectrum, the angle of the leaves and the distribution and density of foliage.

The study quickly found answers that would have required decades of crossbreeding in the field, according to Drewry. Plant hybridizers address one trait at a time, and creating a new prototype typically takes several generations — with no guarantee the trait in question is the most critical one for meeting the hybridizer’s goal.

Seed collections — for example, the U.S. Department of Agriculture's Soybean Germplasm Collection of about 20,000 varieties from around the world — are likely to contain the genetic material needed to breed a soybean plant with these traits. Crop-management choices might also be able to produce soybean canopies with the desired traits.

Compared to many of the so-called geoengineering solutions that have been suggested for climate change, such as spraying sulfates into the upper atmosphere to reduce incoming sunlight or loading the ocean with iron to increase plankton photosynthesis, modifying annual crop covers is inexpensive, can be implemented quickly and is reversible.

“Many proposed geoengineering solutions require significant resources, and we don’t know all of the potential downstream effects,” Drewry said. “If changing an annual crop has an unforeseen consequence, we can simply return to the one we grew the previous year.”

More information about NASA's Earth science activities in 2014 is available on the agency’s website.

 

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Posted 2014-04-17 17:33:00