Kernza: The 50-Year Bet on Perennial Grain
The first example from the Perennial Polycultures mini-series.
What Kernza is
Kernza is the trademark name for grain harvested from improved varieties of intermediate wheatgrass, Thinopyrum intermedium. It is a perennial grass related to wheat — close enough that modern plant breeders could envision turning it into something farmers could harvest.
The plant originates from Europe and Asia, more specifically the Caucasus region and has been in North America since 1907, when the USDA first imported it as a forage crop. It grows well on marginal land, tolerates drought, and builds deep root systems — up to ten feet (3 metres) — that hold soil and sequester carbon. What it did not do, in its wild form, was produce seeds large enough or abundant enough for humans to eat economically.
The breeding program to change that began in the 1980s at the Rodale Institute, moved to the Land Institute in 2003, and has been ongoing ever since. The goal was never modest: to create a grain crop that could be harvested for multiple years without replanting, delivering the soil and ecological benefits of perennial prairie while producing food.
Today, Kernza can be harvested for both grain and forage. The grain has a nutty, slightly sweet flavor — one scientist describes it as hints of cinnamon and nutmeg. It produces flour, pasta, beer, and breakfast cereal. The forage can be grazed or hayed. The roots stay in the ground year-round, holding soil and feeding microbial communities in ways that annual wheat cannot.
How far the breeding has come
The breeding progress is real, but slow by the standards of modern agriculture.
In the first two decades, advances came in fits and starts. Limited funding meant limited breeding populations. Then, in the 2010s, federal grants and genomic selection began accelerating the work. Scientists for Kernza domestication at the Land Institute, have compressed the breeding cycle from five years to one year. As of 2025, The Land Institute reports completing "two breeding cycles in one year, effectively doubling the rate of Kernza development."
The results show in multiple traits. Seed size has increased substantially — though it remains at about 25% the size of conventional wheat kernels. Shatter resistance has improved, meaning fewer seeds fall to the ground before harvest. Free-threshing ability has advanced, making seeds easier to remove from hulls during processing. Plant breeders are selecting for stronger stems that resist lodging, better grain quality, and higher yields.
Six Kernza varieties are now commercially available. The first, MN-Clearwater, was released by the University of Minnesota in 2019. New varieties released in 2022 show up to 20% higher yields than MN-Clearwater, with improved traits across the board.
Four breeding programs now work on Kernza: the foundational program at The Land Institute, programs at the University of Minnesota and University of Manitoba, and USDA-ARS at Utah State University. The breeding targets for the next ten years are specific: increase grain size to 50% of annual wheat (from the current 25%), improve yields, and extend productive lifespan in the field.
Current yields and scale
Kernza yields are improving, but they remain far below annual grain crops.
Current Kernza yields range from 400 to 900 pounds per acre (450 to 1,010 kg/ha) in the first year, with research trials achieving up to 1,000 pounds per acre (1,120 kg/ha) under ideal conditions. For comparison, conventional wheat in Kansas averages about 3,000 pounds per acre (3,360 kg/ha). Kernza produces roughly 20-30% the yield of annual wheat — a gap that breeding efforts are working to close, but slowly.
In 2025, approximately 4,000 acres (1,620 hectares) of Kernza were grown across 15 U.S. states and 10 countries — up substantially from an estimated 500 acres (200 hectares) in 2019, but still microscopic compared to the hundreds of millions of acres under annual cereals globally. Minnesota and Kansas have the most acres, with Montana emerging as a significant new hub.
The economic picture is mixed. Kernza typically sells for premium prices — recent figures suggest $3-5 per pound (€6-10 per kg) for cleaned grain — which can offset lower yields for niche markets. However, volatile pricing and limited market infrastructure mean most Kernza goes into specialty foods rather than commodity markets.
The crop is dual-use: farmers can harvest both grain and forage from the same field. Forage yields can reach 5 tons per acre (11.2 tonnes/ha) on top of grain production. For operations that can utilize both outputs, this changes the economics considerably.
Beyond North America: the international experiment
While Kernza development began in the United States, the perennial grain is now being tested across multiple continents, each with different motivations and constraints.
The most systematic international work is happening in Northern Europe. The Nordic-Baltic "Viking" project is testing Kernza across Sweden, Norway, Finland, Estonia, and Lithuania — countries where winter hardiness and cold tolerance are critical. Preliminary results from Lithuania show grain yields reaching up to 2 tonnes per hectare (1,780 pounds per acre), among the highest recorded yields for the crop globally.
Sweden has been the European pioneer, with trials running for about ten years. The focus there is different from the American approach: less emphasis on replacing commodity grains, more emphasis on dual-use systems where Kernza provides both forage for livestock and grain for specialty markets. Swedish researchers have found that when forage and grain are combined, the total economic output can justify cultivation.
Canada represents the closest parallel to U.S. conditions. University of Manitoba researchers have been testing Kernza intercropped with legumes like alfalfa and red clover, aiming to reduce nitrogen fertilizer needs while maintaining yields. Canadian trials achieved 519 kg per hectare (463 pounds per acre) in the first year and 446 kg per hectare (398 pounds per acre) in the second year. This intercropping represents one of the few examples where Kernza moves beyond perennial monoculture toward actual polyculture — most Kernza production remains a single-species perennial system.
European interest in Kernza reflects a different agricultural context than the United States. EU farming faces stricter environmental regulations, higher land costs, and stronger policy support for ecosystem services. In this context, Kernza's environmental benefits may be valued more highly through payments for carbon sequestration, water protection, or biodiversity conservation — revenue streams that do not yet exist at scale in U.S. markets.
The international trials also test a fundamental question about perennial grains: are the challenges Kernza faces in the American Midwest universal, or are they specific to certain climates and farming systems? Early data suggests the answer is mixed — winter hardiness appears strong across Nordic climates, but yield challenges and the third-year decline remain consistent across locations.
The bottlenecks
Four major constraints limit Kernza's expansion, and none of them are simple to solve.
The yield gap. Kernza produces 20-30% of what annual wheat produces per acre. The Land Institute projects that breeding could close this gap within "about another 17 years," but skeptics point to a lack of evidence that perennial grains can ever match annual crop yields. The biological tradeoff may be fundamental: resources devoted to maintaining perennial root systems may always come at the expense of seed production.
Yield decline over time. Kernza fields are most productive in their first year. Yields can decline by as much as 50-70% by the third year due to plant competition, tillering, and self-seeding that increases plant density. Researchers are testing management practices — fall tillage, spring herbicide application, mechanical thinning — to extend productive lifespan, but the fundamental problem remains: the crop becomes its own weed.
Harvesting challenges. Kernza ripens from the top of the seed head down, creating a narrow harvest window. Seeds at the top may shatter and fall before seeds at the bottom are ready. The small seed size and tendency to shatter make combining difficult — there are no "Kernza settings" on standard farm equipment. Most producers swath the crop and let it dry before combining, adding labor and weather risk.
Market infrastructure. Kernza lacks the processing, grading, and distribution systems that support annual grains. Farmers often have nowhere to sell it locally. Cleaning equipment, storage protocols, and food-grade processing remain underdeveloped. The grain's small size and unique properties require specialized handling that most elevators and mills do not have.
The case for persistence
Despite these constraints, the case for continuing Kernza development rests on three arguments.
Environmental benefits that annual grains cannot match. Research in Minnesota shows Kernza absorbs 200 times more soil nitrate than annual cropping systems, preventing groundwater contamination. Its 10-foot (3-metre) root system builds soil carbon at rates annual crops cannot approach. These ecosystem services have value, even if markets do not yet capture it.
Breeding momentum that is accelerating, not slowing. Genomic selection and modern breeding tools are speeding progress beyond what traditional methods achieved. Early breeding cycles improved yields by 77% in two generations — a pace that, if sustained, could close yield gaps faster than historical domestication timelines suggest. The four breeding programs now working on Kernza represent more scientific attention than the crop has ever received.
Market traction that creates incentives for further development. General Mills' expansion of Kernza use signals corporate interest in perennial grains. Small-scale value chains are emerging in Minnesota, Kansas, and Montana. Premium pricing for specialty markets provides early revenue streams that fund continued breeding. While markets remain niche, they are growing.
What the experiment tests
Kernza is fundamentally a test of whether modern plant breeding can compress thousands of years of crop domestication into decades. The wild grasses that became wheat, maize, and rice were domesticated over millennia by civilizations that could afford to take generations perfecting their food systems. Kernza's breeders are trying to accomplish similar domestication in the span of a scientific career.
The broader question Kernza poses is whether perennial crops — even as monocultures — can deliver on their ecological promise while remaining economically viable. If a single perennial grain crop struggling to reach 30% of annual wheat yields after four decades of breeding, what does that suggest about the scalability of more complex perennial polyculture systems?
Or, alternatively: if Kernza represents the early stages of a new agricultural paradigm — if the yield gaps can be closed and the market infrastructure built — what does that open up for the perennial polycultures that would follow?
The answer will not come from the lab drawers at the Land Institute. It will come from the fields where Kernza is grown, season after season, under the economic and ecological pressures that determine what agriculture actually becomes.
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