Research Breakthrough Could Increase Grazing Sorghum in Northern Climates


After many years of research, a team at Purdue University in West Lafayette, Indiana has developed a breakthrough that could lead to increased use of grazing sorghum in northern climates where frost conditions prevented such a forage program for livestock producers. Purdue’s Dr. Mitch Tuinstra says grazing sorghum has many benefits, but it also produces a secondary metabolite called dhurrin.

“High dhurrin concentrations in the forage can lead to cyanosis in animals feeding on the forage, meaning they can be toxic and release cyanide gas, or sometimes this is known as prussic acid poisoning. Producers have to be careful and manage it properly to avoid any risk of prussic acid poisoning.”

Higher concentrations of dhurrin develop as cold and frost arrive, further incentivizing research to develop a dhurrin-free sorghum; “Twelve years ago already we began a research project to see if we could disrupt this pathway in sorghum so that the plants would not produce dhurrin, and we’ve been successful in that research activity, and we’ve incorporated this new dhurrin-free trait into sorghum sudan grass hybrids. We’ve had a whole series of research projects going on the last few years exploring the nutritional value of this new crop, exploring the safety and safety benefits, evaluating differences in palatability of dhurrin-free versus conventional sorghum, and the results have all been very, very positive.”

Because of its benefits, sorghum for pasture has been a favored option around the country and around the world. “For many, many years sorghum sudan hybrids have played an important role in providing pastures for livestock producers. It’s adapted to dry environments. It’s a low-input crop. It’s very resilient to potentially the effects of climate change in terms of adaptation to high temperature stresses and drought stresses.”

Dr. Shelby Gruss is a Purdue post-doctoral scholar. Dr. Tuinstra credits her work on the dhurrin-free sorghum project.

“Shelby has been instrumental in helping us evaluate the nutritional quality and safety characteristics of this new genetic technology and it’s really been largely based on her work and drive that we’ve really made a lot of progress in the last few years in developing and now pushing commercialization of this new trait in sorghum.”

The researchers teamed with Ag Alumni Seed Company and S & W Seed Company to develop and commercialize the seed and bring it to market. Tuinstra says they’re working closely together to further develop the trait and develop hybrid products that farmers can buy and grow in their pastures, possibly within the next two years.

Tuinstra is the Wickersham Chair of Excellence in Agricultural Research and Professor of Plant Breeding and Genetics at Purdue.