University of Georgia
Say "sorghum" in many parts of Georgia, and the topic may turn to the values of sorghum syrup. Wait a few years, though, and that same biscuit-topper may be the center of a biofuels discussion.
Like many crops, grain sorghum has trouble thriving in Georgia's typically humid climate. But both statewide and nationwide, its worth is growing.
"At the moment, sorghum is the No. 2 bioethanol crop in the country," said University of Georgia scientist Andrew Paterson. "Bioethanol is currently produced from seeds. There are a number of reasons why we'd want to use the whole plant."
With a farm-sales value of $3.2 million, sorghum ranked No. 56 among Georgia crops in 2005, between apples and okra. As a seed-based ethanol crop, sorghum falls right below corn.
"Grain sorghum is a good substitute for corn," said agricultural economist John McKissick, director of the UGA Center for Agribusiness and Economic Development. The center is studying the feasibility of growing sorghum and other crops for biofuel in Georgia.
What sets sorghum apart as a prospective whole-plant-based ethanol crop is that sorghum can easily be made perennial. Coming back year after year, perennials aren't as prone as annuals to causing erosion, Paterson said.
Sorghum efficiently converts the sun's light into energy and needs only about half the water of corn. That makes it a prime candidate for further ethanol studies.
"It can easily make the transition from seed-based to whole-plant-based biofuels," Paterson said.
This transition has already happened with sorghum's cousin, sugarcane, which is grown in the U.S.'s tropical climates. Sugarcane is the No. 1 ethanol-producing crop worldwide, he said.
When it comes to sorghum, Paterson's research focuses deeply on the plant itself, not necessarily its by-products: food, feed, ethanol and alcoholic beverages.
Paterson has spent 15 years studying sorghum's genetic blueprint. He's hoping now to find answers: Why is the plant more drought-resistant than corn? How did it get its genetic makeup? What genes give certain plants height and others disease resistance?
"First we built a genetic map of sorghum," Paterson said. "It's kind of like the mileposts on a highway. We had the mileposts but not the asphalt between them. There was still a lot we didn't know."
Recently, the U.S. Department of Energy completed the sequencing of sorghum at its Joint Genome Institute, collaborating with Paterson's lab and several others.
"It's a huge advance," he said of the JGI's work. "It's happened much more quickly than we expected."
Paterson, a distinguished research professor in the UGA College of Agricultural and Environmental Sciences' crop and soil science department, is also director of the UGA Plant Genome Mapping Laboratory (www.plantgenome.uga.edu).
And now, thanks to a fellowship from the John Simon Guggenheim Memorial Foundation, he can examine sorghum's 740 million bases, or letters, more thoroughly. At 740 million letters of DNA, sorghum has a genetic code roughly a quarter the size of the human genome.
Guggenheim Fellows are appointed for their distinguished achievement and exceptional promise and receive a grant to use in their research.
"I think the most interesting outcome of this work," Paterson said of the fellowship, "is that for the first time, we'll have a picture of diversity among the cereals. Years ago, they sequenced the rice genome, and it was the only one for a while. Sorghum and rice are quite different."
Through computer models, he'll be able to deduce what the sorghum gene set looks like. And he can build hypotheses on why sorghum has certain traits such as height, flowering and disease resistance that can be tested in the field.
"Sorghum is important now as a promising biomass," Paterson said. As the demand for biofuels increases, understanding the plant's building blocks grows in importance, especially as scientists look at moving from seed-based to plant-based biofuels.