Salt-tolerant trait may unlock land for energy, food crops

By Anna Austin
Researchers at energy crop development company Ceres Inc. say a newly developed genetic trait that increases the salt tolerance in plants could potentially enable the revival of more than 1 billion acres of abandoned crop land across the globe, for both energy and food crop purposes.

Upon analysis of a 2008 Stanford University study, "The Global Potential of Bioenergy on Abandoned Agriculture Lands," Ceres researchers inferred that a massive amount of land was unproductive and could benefit from trait improvements such as salt tolerance and others that make crops hardier and more resilient to stress, according to Ceres's Gary Koppenjan. "As reported by the U.S. Salinity Lab, there are 15 million acres in the U.S. where productivity is limited by salt buildup in the soil," he said. "This is especially problematic in California, and other areas where irrigation is used."

Salt has been damaging to land in other parts of the world, too. "It's been a problem in Asia, where coastal flooding is common, and a staple crop-rice-is quite sensitive to salt. It's also a problem in the developing world, where cropping practices and poor drainage damage cropland," Koppenjan said, adding that although salt is not currently a nuisance in the Midwest, where most of the row crops are grown, in the future it will likely be a bigger problem on the marginal acres where energy crops are being targeted.

So far, Ceres's work has focused on improvements in switchgrass and rice in a greenhouse. Researchers tested the trait against high salt concentrations, including trials where they dumped sea water from the Pacific Ocean onto the soil, and saw a significant salt tolerance. "We have seen [salt tolerance] levels five times greater than any previously published results," Koppenjan said. The salt tolerance improvement will likely work in other energy grasses as well, Ceres believes, including sorghum and miscanthus.

Crop yields now need to be measured in the field, tests which Ceres plans to begin next year. Koppenjan noted that initial work was completed in a test plant used primarily for greenhouse testing (not a crop plant), a method that provides trait development advantages such as precision and a plug-and-play ability to add the trait to other crops. "Typically, we use rice as a model crop to study trait performance since it is a grass species, easy to work with and predictive of how traits will work in energy crops," he said. "Since the results were so impressive, we decided to move forward with additional work in rice for both business and humanitarian reasons. Clearly, rice is an important and valuable crop, but there are areas in the world like coastal region of Bangladesh where salt-tolerance would provide basic food security for millions of people."