Origin of current intermediate wheatgrass germplasm being developed for Kernza grain production

Authors: WAGONER, PEGGY - Retired Non ARS Employee; CRAIN, JARED - Kansas State University; Larson, Steven; DEHANN, LEE - The Land Institute

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2024
Publication Date: 3/30/2024
Citation: Wagoner, P., Crain, J., Larson, S.R., Dehann, L. 2024. Origin of current intermediate wheatgrass germplasm being developed for Kernza grain production. Genetic Resources and Crop Evolution. https://doi.org/10.1007/s10722-024-01952-1.
DOI: https://doi.org/10.1007/s10722-024-01952-1

Interpretive Summary: Intermediate wheatgrass has been developed as a dual-purpose perennial forage and grain crop to provide ecosystem services, environmental benefits, and human food. In the 1980’s, a joint breeding effort between the Rodale Institute and the USDA Big Flats Plant Material Center used intermediate wheatgrass collections from the USDA National Plant Germplasm System to breed intermediate wheatgrass as a perennial grain crop. Initial selections were provided to The Land Institute, which continues developing intermediate wheatgrass as a perennial grain crop under the Kernza trademark. However, the identity of the original collections has not been publicly documented until now. Partially complete records from the Rodale Institute were used to reconstruct the early breeding program to identify the most likely 20 collections used to initiate their intermediate wheatgrass grain breeding program. Moreover, DNA sequence data from current breeding programs were compared to remnant seed and leaf tissues from the initial selections from the Rodale Institute. Results of the DNA analysis provided supporting evidence for the historical records. Most of the putative source materials were collected between the Black Sea and Caspian Sea in or near the Stavropol region of Russia. As intermediate wheatgrass domestication now involves an international research effort and at least six different breeding programs, this work documents the origin and transfer of germplasm from the USDA National Plant Germplasm System to present day Kernza cultivars.

Technical Abstract: Intermediate wheatgrass (IWG, Thinopyrum intermedium [Host] Barkworth & D. R. Dewey) has been developed as a perennial grain crop to provide ecosystem services, environmental benefits, and human food. Grain and products derived from IWG varieties improved for food production have been marketed under the trade marked name Kernza. In the 1980’s, a joint breeding effort between the Rodale Institute (RI) and the Big Flats Plant Material Center used IWG plant introductions (PI) from the National Plant Germplasm System (NPGS) and recurrent phenotypic selection to improve populations of IWG with the goal of developing a perennial grain. Initial selections were provided to The Land Institute which were subsequently improved for grain production. As the NPGS gene bank has hundreds of IWG accessions from diverse regions of Eurasia, the identity of the founder material of improved, food-grade IWG has not been publicly documented. Recently recovered original documents have been used to reconstruct the early breeding program to identify the most likely 20 PIs that form the founders of modern food-grade IWG. Molecular data using genotyping-by-sequencing in current elite breeding material, remnant seed from the initial RI selections, and preserved sample material have provided supporting evidence for the historical records. Many of the founders for food-grade IWG were collected between the Black Sea and Caspian Sea in the Stavropol region of Russia. As IWG domestication now involves an international research effort and multiple breeding programs this work connects the flow of germplasm and utility of NPGS PIs to present day IWG grain cultivars.