Perennial wheat (Thinopyrum intermedium) is a perennial relative of wheat that has been bred in the USA for grain and forage production. With its deep-growing roots, the species is drought-tolerant, has good carbon/nutrient storage capacity, and provides strong protection against erosion—making it relevant for climate challenges. Products from varieties bred for grain production are often marketed under the trademark ‘Kernza’ (e.g., Kernza flour). Kernza flour contains higher levels of protein (67%) and fiber (109%) than regular wheat, making it a healthier alternative.
The main goal of the project is to determine the potential of the species for grain and forage production in the Nordic and Baltic regions. The project is organized into five work packages (WP). WP1 focuses on optimal nutrient supply to achieve maximum grain yields and whether intercropping with nitrogen-fixing legumes (red clover) has a positive effect on yield levels. WP2 investigates the wheat grass as a forage producer, while WP3 examines optimal growing conditions in the Nordic and Baltic regions, especially regarding winter hardiness of Kernza wheat. WP4 focuses on mapping the environmental and resource impacts of Kernza cultivation (“life cycle assessment”), and WP5 is dedicated to various dissemination activities to increase interest in growing and using Kernza wheat.
The Norwegian contribution to the project is mainly within WP1, where the potential of Kernza wheat for grain production is tested in two different climatic regions in Southern Norway: coastal areas at NIBIO Landvik in Grimstad and inland conditions at NIBIO Apelsvoll in Østre Toten.
The experimental fields with perennial wheat in WP1 were sown in 2023, either as pure stands (in each row) or intercropped with red clover in alternating rows. The pure stand plots were fertilized in spring of the first (2024) and second harvest years (2025) with either 0, 7, or 14 kg/daa of nitrogen. These plots were not growth-regulated later in the season. Additionally, one treatment was heavily fertilized in spring (14 kg N/daa) and later sprayed with 80 ml Moddus Start/daa at BBCH 31. The intercropped plots with perennial wheat and red clover in alternating rows were either unfertilized or spring-fertilized with 7 kg N/daa. As controls, plots with either regular spring wheat or red clover in pure stands (sown in each row) were included. The spring wheat was split-fertilized with 11 kg N/daa in spring and 4 kg N/daa at flag leaf stage (BBCH 45–49).
So far, the overwintering ability of the perennial wheat has been excellent (100%) at both Landvik and Apelsvoll. Regarding grain yield, both fields were harvested in 2024 (first harvest year) and 2025 (second harvest year), but since the 2025 grain is not yet cleaned, only yield results from 2024 are currently available.
In pure stand plots without growth regulation, grain yield in 2024 increased when spring nitrogen application rose from 0 to 7 kg N/daa at both sites. Further increase from 7 to 14 kg N/daa led to higher yield at Apelsvoll (41%) but not at Landvik, where denser stands and lodging pressure were stronger.
The highest grain yields in 2024—95 kg/daa at Landvik and 39 kg/daa at Apelsvoll—were obtained in plots fertilized with 14 kg N/daa and where lodging, especially at Landvik, was controlled by growth regulation with 80 ml Moddus Start/daa. As long as lodging was kept in check, strong nitrogen fertilization was particularly beneficial for increasing the density of reproductive tillers.
Yield results from the first harvest year indicate that significant breeding work remains to increase grain size and yield level of perennial wheat to match current winter and spring wheat varieties. For comparison, spring wheat yielded 530 and 368 kg/daa at Landvik and Apelsvoll, respectively.
In the intercropped plots, perennial wheat plants grew very slowly after germination and competed poorly against the “aggressive” red clover plants. This led to red clover almost completely dominating both fields already in the sowing year. At Landvik, competitiveness improved slightly with spring fertilization of 7 kg N/daa in the first grass year, but grain yield remained very low (25 kg/daa). At Apelsvoll, no spikes produced seed regardless of fertilization strategy. So far, the experience is that perennial wheat should be established in pure stands and not intercropped with red clover.
In both experimental fields, plots will be harvested again in 2026 (third harvest year).
Kernza (Intermediate wheatgrass) is a perennial grass relative of wheat and recently domesticated as a perennial grain and forage crop in North America. Demand for perennial grain food products, like Kernza beer and baked goods, is increasing. As a perennial deep-rooted crop, Kernza is very drought and cold tolerant. However, little is known about the adaptation and productivity of this novel crop in the Nordic and Baltic countries, as well as which agronomic management practices may optimise the grain and forage production. The main objective of this project is to strengthen research collaboration between Sweden, Norway, Finland, Estonia, Lithuania, and Denmark to explore the adaptation and potential of grain and forage production and quality of Kernza across the Nordic and Baltic region. The role of the Norwegian research activity is mainly to test Kernza grain production under different climatic growing conditions. The selected locations for the Norwegian field trials are the southern coastal location NIBO Landvik in Grimstad and the inland eastern location NIBIO Apelsvoll in Østre-Toten. At both locations, experiments will be carried out to optimize the nutrient supply and investigate the effect of inter-cropping Kernza with a nitrogen-fixing legume (red clover) as a companion crop, especially with regard to grain yield level and quality. In addition, a special focus will be on winter hardiness studies, as well as assessing the environmental impacts associated with growing Kernza-wheat (Life Cycle Assessment).
