Sorghum is a tropical grass species originally domesticated as a grain crop in sub-Saharan Africa about 8,000 years ago.
Among the major cereal crops, grain sorghum is most closely related to the perennial species Sorghum halepense, or Johnsongrass. That presents an opportunity to develop perennial grain sorghum by hybridizing annual sorghum, Sorghum bicolor, with S. halepense.
In much of Africa and South Asia, sorghum is consumed in flat breads, porridges, couscous, beer, and other products. It can be used to make tortillas as well. In the United States, sorghum flour is increasingly being used in all kinds of processed foods, similarly to corn meal or flour.
History of the Sorghum Breeding Program
The Land Institute, working with Kansas State University, began making crosses between annual sorghum and S. halepense in the 1980s. The long-term goal was to develop populations of perennial sorghum that could produce repeated, sufficient grain harvests without resowing. This new crop would fit into food-producing ecosystems.
In 1994, Land Institute scientists Jon Piper and Peter Kulakow published a study of S. bicolor x S. halepense hybrid populations, concluding that perennial grain sorghum was a feasible goal.
However, the full-fledged breeding program aimed at developing perennial sorghum started almost a decade later, in 2003, with initial crosses between hardy perennial plants drawn from Piper and Kulakow’s populations and grain sorghum parental lines developed at universities in the United States.
Where We Are Headed
The Land Institute and its research partners are currently selecting for perennial growth habit and grain productivity in diverse environments in the United States and several African countries.
Breeding perennial sorghum in Kansas means selecting perennial plants that can endure very cold winters. Our populations are also being evaluated at Texas A&M University, the University of Georgia, and Bologna, Italy, where winters are milder, as well as in Mali, Uganda, the Republic of South Africa, China’s Yunnan Province, and the Indonesian island of Bali, to evaluate for ecological adaptation in tropical and semitropical climates.
Early results are promising, suggesting that it may be worthwhile to cross regionally adapted annual varieties from different parts of Africa with perennial sorghum. You can read more about these research collaborations here.
Slow, Steady Progress Toward Perennial Yield
Although it could take anywhere from 10 to 30 years to have a commercially viable perennial sorghum variety, we see progress every year in key traits like perenniality and grain production. These are both complex traits governed by large complexes of genes, so progress in combining those traits is gradual year by year.
In 2016 Land Institute researchers published a study based on field experiments done in 2011-13 showing that selection during the first seven years of the program (2003-09) had produced perennial lines with almost triple the grain yield of the perennial parents we had started with in 2002. That was a yield increase of about 27 percent per year.
Each year since 2009, we have selected perennial lines with successively higher yields and more crop-like plant traits. This is a good sign that our goal is feasible and that this work should continue.
Stan talks about progress on perennial sorghum at the 2018 Prairie Festival.
Related Scientific Publications
Learn about other perennial crops under development at The Land Institute.