Breeding transforms sorghum’s potential as biofuel of the future for northern latitudes

Woman with dark hair in black top
Maria Salas-Fernandez. Iowa State University photo. 

AMES, Iowa - The biofuel of the future may well be sorghum-based, thanks to new inbred lines that are significantly more productive and cold-hardy than sorghum plants of the past.

Maria Salas-Fernandez, associate professor of agronomy, developed the lines, recently released through Iowa State University, with improved genetics capable of producing hybrids that deliver high biomass yields adapted to northern latitudes.

Sorghum is a popular crop worldwide, used primarily as grain, livestock feed and sweetener. Until now, the plant, which originated in the tropics, has done best in warmer regions with longer growing seasons than the upper Midwest. The new Iowa State lines break through this challenge by producing “photoperiod-sensitive hybrids,” which means they don’t flower or produce grain. This allows the hybrids to grow longer, accumulating biomass until the first frost, up to a month later than traditional sorghum plants.

“Sorghum has great potential as an energy crop,” Salas-Fernandez said. “Our new lines, IA100RPS and IA101RPS, produce hybrids with three times more dry matter than corn stover, yet need less nitrogen to grow.”

The biomass productivity of the hybrids generated with the new lines even exceeds miscanthus, a perennial adapted to cold environments and investigated for biofuels.  

“Sorghum offers a number of economic and environmental benefits,” she said. “The seed is cheaper than corn, and it grows well with fewer inputs of pesticides and fertilizer. At the same time, it is an annual crop that uses similar equipment and familiar cultivation methods, so it fits well with conventional crop rotations in this region.”

The breeding lines she created also have improvements over traditional sorghum. Their better standability means the resulting hybrids are less prone to lodging, a condition where plant stems fall over in heavy wind or rain. In addition, the plants’ biomass has a low ash content when burned, which is desirable for some biofuel conversion technologies.

The new lines are featured in a recent publication in the Journal of Plant Registration by Salas-Fernandez and co-author Joshua Kemp, a research scientist in agronomy who helped manage the sorghum breeding program.

This success represents almost a decade of breeding and testing at multiple locations in Iowa. Interested collaborators in North Dakota, Wisconsin and Michigan also conducted their own tests.

“Even in states farther north, the results have been consistent with biomass yields superior to other commercial and public germplasm,” according to Salas-Fernandez.

Now, the Great Lakes Bioenergy Research Center plans to experiment with the crop under an agreement with Salas-Fernandez to produce the seedstock needed.

“Dr. Maria Salas-Fernandez’s sorghum hybrids carry the genetics needed to best fit our bioenergy experimental sites located in Michigan and Wisconsin. They perform well under our more northern growing conditions and produce excellent yields,” said Kurt D. Thelen, a professor with the Department of Plant, Soil & Microbial Sciences at Michigan State University, and a cooperating faculty with the Great Lakes Bioenergy Research Center.

Salas-Fernandez’s mission to breed sorghum as a bioenergy crop suited for the north-central United States began soon after she came to Iowa State in 2008. Sorghum’s diverse uses and benefits, including its productivity and drought-tolerance, first caught her interest when she was employed in industry in Argentina, her home country.

Her related research includes working with other scientists at Iowa State to increase sorghum’s biomass by altering plant architecture.  “We are developing plants with an optimized distribution of leaf angle across the plant that can allow more light to penetrate the canopy and increase overall photosynthetic capacity,” Salas-Fernandez said. “That will increase the plants’ efficient use of sunlight and its potential for growth.”

Sources of support for research on the new sorghum lines include the U.S. Department of Agriculture National Institute of Food and Agriculture, the R.F. Baker Center for Plant Breeding at Iowa State, the College of Agriculture and Life Sciences, the Department of Agronomy and the Iowa Crop Improvement Association.

Field showing tall sorghum ready to harvest.
Harvest-ready growth of one of the new productive, cold-hardy sorghum hybrids generated with parental line IA100RPS developed by Iowa State University. Photo courtesy of Joshua Kemp.