A COMMON weed growing in North America, pennycress, could soon be added to a farmer's corn/soybean rotation.
University of Minnesota (UM) researchers are working to unlock its potential as a new cover and oilseed crop.
A year ago, Don Wyse, professor of agronomy and plant genetics in the UM College of Food, Agriculture & Natural Resource Sciences who has a longstanding interest in pennycress, asked David Marks, professor of plant biology in the College of Biological Sciences, to collaborate on a research project investigating the promising traits of pennycress. Under their guidance, plant biology graduate student Kevin Dorn has been working to identify and sequence the genes.
"Adding pennycress to a traditional cropping system addresses both the large-scale environmental issues caused by traditional agriculture and the dilemma of using land for food or fuel. It wouldn't displace food crops," Dorn said.
Native to the Mediterranean region, pennycress was introduced to the U.S. in the 1700s. As a non-food member of the mustard family, it naturally germinates in the fall and provides a living cover crop over the winter. In the spring, the plant continues to grow, flower and produce seed.
For the past 10 years, the U.S. Department of Agriculture's National Center for Agricultural Utilization Research has investigated pennycress as an energy crop.
In 2009, Western Illinois University, in collaboration with USDA, initiated the first breeding program to develop genetic varieties and continues to work toward optimizing agronomic methods for raising pennycress as a crop.
According to USDA research, pennycress can be planted with traditional grain drills and grass seeders into corn stubble in the fall, and no additional fieldwork is required. In late May, the seeds can be harvested, and soybeans can be planted immediately into pennycress stubble.
Pennycress produces seeds with 36% oil when crushed — twice as much as soybeans — and it has a chemical composition that is ideally suited for biodiesel. According to the USDA research, one acre can produce 1,500-2,000 lb. of seeds, and a ton of seeds can produce 150 gal. of fuel.
Although there has been a grassroots effort over the past several years to develop pennycress as a crop, it has not been widely adopted by farmers, mainly because growing the crop is still consider experimental.
Also, Pennycress Energy Co. LLC in Peoria, Ill., is the only commercial market available. In 2012, Pennycress Energy contracted 1,600 acres in its pilot stage.
Similar to the research in Illinois, the UM team recognizes the environmental benefits of raising pennycress.
"The development of field pennycress as a crop is part of the University of Minnesota Forever Green Agriculture Initiative," Wyse said. "The initiative is designed to develop new winter crops that will enhance yields of summer crops, enable production of new commodities, enhance soil quality and wildlife habitat and improve our water resources."
Since pennycress only recently became a prospective crop, the plants are just a few generations away from their wild ancestors. The agronomic improvement in pennycress through traditional breeding has been limited. Recent advances in genomic tools enable scientists to rapidly improve plant genetics through genomic assisted breeding.
Dorn has identified all of the estimated 33,873 genes in the pennycress genome, which is a huge step toward selecting genes for traits that will realize the plant's agricultural potential. The results were published online last week in The Plant Journal.
Some of the genes Dorn and his advisers have already discovered control levels of chemicals called glucosinolates in the seeds.
If plant breeders can reduce glucosinolate levels, the seeds could be used for animal feed after they've been pressed for oil. Other genes control flowering time, which will help the researchers produce plants that develop earlier in the spring.
The next phase for the UM research team will be to induce natural genetic variations in tens of thousands of pennycress plants and screen them for genes that will suppress undesirable traits and promote desirable traits. The researchers will use traditional breeding strategies to introduce selected genes into plants for agricultural use.
"These are standard approaches that have been used to improve crops for a long time. This isn't genetic modification," Dorn explained.
Knowing the sequence will help the researchers understand more about the function of individual genes.
Dorn and Marks expect to complete the pennycress genome sequencing and publish their results within the next few months.