A transdisciplinary perennial grain research conglomerate containing scientists from across the US and in France collaborated on a comprehensive study of Kernza® perennial grain agronomics, utilization, markets, ecosystem services, and more, underscoring the need to simultaneously advance breeding efforts and market expansion to achieve greater success with this emerging perennial grain crop. 

Abstract

Intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D.R. Dewey) is a perennial grass that has been explored for use as a perennial grain since the 1980s. With growing recognition of the potential for perennial grains to improve soil quality, sequester carbon, and reduce nitrate leaching, research with the species has expanded rapidly since 2010. However, introducing a new crop requires coordination across a wide array of research fronts and commercial development activities. The grain, sold under the registered trade name Kernza, has been used to develop commercial products, but high prices for the grain and intermittent supply have limited use. Market growth depends on increased yields through breeding and agronomic improvements, combined with development of cost-effective regional processing. Therefore, we reviewed the current knowledge base surrounding intermediate wheatgrass as a grain crop to summarize available information and suggest future directions. Evidence for the environmental benefits of Kernza on water quality and soil health is growing. While perennial grasses generally increase stored soil carbon, long-term cropping system experiments are required to accurately predict landscape-scale impacts of this new crop on soil carbon stocks, in interaction with crop rotation and pedoclimatic parameters. Studies have revealed the importance of soil nitrate availability in determining grain yield, and fertilizer recommendations are available for some regions. However, the role of other nutrients and the potential for legume intercropping to supply nitrogen remains uncertain. Improved techniques are urgently needed to sustain seed yields in aging stands across diverse environments. Expanding markets will be essential for success.