Sugarcane, corn hybrid to be tested in US

By Ryan C. Christiansen | January 03, 2009
During the 2009 growing season, Targeted Growth Inc., a crop biotechnology company based in Seattle, Wash., will observe Sugarcorn, a hybrid plant that's a cross between sugarcane and corn. The test plots will be located across the U.S., east to west from Indiana to Nebraska, and spanning north to south from Minnesota to Florida.

During the 2008 growing season, the company tested growing Sugarcorn in Illinois and Indiana plots. "We've had two years worth of good field data in a couple of states, but we really need to get this spread out across a lot of environments in the Midwest to get a better handle on that," said Donald Panter, senior vice president for crop development at Targeted Growth. "We need to try to get a handle on what is the hardiness of these plants, how well do they grow in these different growing environments, and what is the impact of different day-lengths on the amount of the biomass and sugar that is produced. Are there certain hybrids that will work better in the southern half of the U.S. versus hybrids that will work better in the northern half of the U.S.?

"We will probably be in a much better position toward the end of 2009, after we harvest, to be able to say, ‘This is what we think is the total energy that can be captured by growing Sugarcorn in the current iteration of the product that we have,'" Panter said.

Sugarcorn includes genes from the germplasm pools of Midwest corn varieties, tropical maize varieties, and sugarcane, Panter said. "You're kind of getting the best from among the three," he said, "the different germplasm pools of corn, but also some of the great genes that you find in sugarcane that make it very efficient."

Essentially corn that doesn't flower to produce grain and instead produces sugar in its stalks, Sugarcorn can grow to be 15 feet high, Panter said. "If you're up at 46 degrees north latitude, it probably won't grow to 15 feet," he said. "But as you move further south and get a longer growing season, it will probably grow that tall."

Panter said Sugarcorn requires no more water than traditional corn and requires less nitrogen fertilizer. However, it must be harvested differently.

"You're talking about really harvesting biomass," Panter said. "This is a crop that could be harvested using a biomass harvester, not unlike what is used for sugarcane. You bring the stalk in, if you can, and you bring that to some kind of a facility that extracts the liquid from the plant and so you would run it through this physical crush." The sugary juice that's extracted from the crush can be directly fermented to produce ethanol.

The remaining biomass is a good candidate for a cellulosic ethanol feedstock, Panter said. "We are in the process this year of looking at that material from Sugarcorn and seeing how it fits in sort of the state-of-the-art of lignocellulosic breakdown," he said. "We will be doing some experiments this year with some labs to help us quantify that. It will not be unlike corn stover, because that's what it is."

Panter is pleased with the 2008 growing season results. "The levels of sucrose that are produced in Sugarcorn are consistent with what our expectations would have been," he said, "which is a pretty significant production of sucrose, which is table sugar.

"There is significant variability out there, as well," he said. "As a genetics company, we are very interested in variability, because we are selecting for things that are on the outside of that curve. We have identified genetic variability that is going to be important for the improvement of the level of sucrose in Sugarcorn. We have also been able to quantify some of the characteristics of the germplasm that we're using to recognize that it can, in fact, work in Midwest corn production."

Panter said researchers are continuing to work on increasing sugar yield in the plant, increasing hardiness for growth in the Midwest, and modifying the plant to prevent it from being pollinated by nearby stands of traditional corn.

Targeted Growth has been working on Sugarcorn for the past two or three years. Panter said the goal is to develop a sugar crop in the U.S. that is competitive with sugarcane in Latin America.

"The basic notion is this: if sugarcane-based ethanol down in Latin America is highly efficient, is there a possibility of developing a crop like that for the temperate parts of North America?" Panter mused. "After having spent some time studying all of the different crops that we might be able to modify to reach that goal of being highly efficient in terms of making ethanol, we looked at corn as really sort of the model crop for being able to do this. What if we make corn produce sugar as sugarcane produces sugar in the tropics?"

For Targeted Growth, the answer is Sugarcorn.