Best thing i’ve read about cannabis /. hemp in the US this year.
Allows for the possibility of gamechanging and full “industry” disruption
On a quiet roadside in Wisconsin, long-forgotten stalks sway in the breeze, disguised as weeds. They’re survivors—ghosts of an agricultural past few Americans remember, and fewer still ever talk about. But Shelby Ellison, a geneticist and assistant professor at the University of Wisconsin-Madison, sees them as something more: the key to jumpstarting a new era of cannabis research in the United States.
“These are the plants that escaped history,” Ellison says, “and now they’re quietly rewriting it.”
In a talk delivered at the 2025 National Association for Plant Breeding meeting in Kona, Hawaiʻi, Ellison captivated an audience of scientists with an unlikely story—one that links wartime fiber production, forgotten seed banks, and the urgent need to rebuild a domesticated cannabis gene pool from scratch. The plant at the heart of it all? Cannabis sativa, better known to some as hemp, to others as marijuana—but to Ellison, simply as a plant with promise.
Rewilding the Genome
To understand Ellison’s mission, you need to go back to World War II. During the “Hemp for Victory” campaign, American farmers were encouraged to grow hemp to replace imported jute and rope. When the war ended, those fields were abandoned. But hemp—being hardy, adaptable, and wind-pollinated—didn’t die out. It went feral.
“Decades later, you can still find these escapees—’ditchweed’—growing across the Midwest,” Ellison explains. “And those plants might hold some of the best untapped genetic diversity available in the U.S.”
The challenge? Finding them.
Armed with a smartphone, a network of collaborators, and a bounty system offering $200 per viable collection, Ellison and her team used the app iNaturalist to locate feral populations from Wisconsin to New York. Each site had to be at least five miles from another—cannabis pollen can drift for up to 10 miles—and collectors were trained to snip just 10 centimeters of flowering tops, enough for DNA, cannabinoid, and seed analysis.
In just a few years, Ellison’s team amassed over 1,800 samples—material that could power decades of breeding.
A Plant, a Puzzle, a Past
Cannabis is dioecious, meaning it has separate male and female plants. It’s also highly genetically diverse. That makes it fascinating—and maddening—for breeders. Throw in decades of prohibition, scattered legacy lines from Europe and Asia, and the legal bifurcation of hemp (less than 0.3% THC) and marijuana (anything more), and you have a scientific Wild West.
The key, Ellison says, is genetic clarity. Using genotyping and principal component analysis (PCA), her team discovered five distinct population clusters among the feral collections. One, in Indiana, showed particularly unique genetic signatures. Even more intriguing was a massive 15-megabase inversion—an ancient twist of DNA—shared by two overlapping populations.
“We think that inversion might trace back to Italian breeding material used in the USDA’s original fiber program,” Ellison says. “It’s like a genetic breadcrumb trail.”
High Stakes, Low THC
For hemp to be legal in the U.S., its THC content must stay below 0.3%. But most legacy cannabis breeding was done with the goal of maximizing THC, not minimizing it. That makes much of the existing germplasm noncompliant—and essentially unusable by today’s farmers.
Ellison’s team screened over 1,400 feral samples using a molecular assay to determine cannabinoid profiles. The results were astonishing: around 80% of samples were type III plants—high in CBD, low in THC, and compliant with federal law.
“That’s a huge win,” Ellison says. “It means we can breed with them right away. They’re local, they’re legal, and they’re surprisingly diverse.”
But about 20% of the plants still carried noncompliant THC-producing alleles—remnants of a time when breeding for psychoactivity wasn’t on anyone’s radar.
“It raises big questions about how we define legality in biology,” Ellison says. “A plant with 0.4% THC isn’t going to get you high—but it might get a farmer in trouble.”
Seeds for the Future
With genotypes in hand and cannabinoid profiles cataloged, Ellison and her team made the most Midwestern of moves: they packed a car full of cannabis and drove it cross-country to Geneva, New York.
“We couldn’t mail it—so we just drove it ourselves,” she laughs.
Now, those seeds live at the USDA germplasm repository under the care of curator Dr. Zachary Stansell, where they’re being grown out, cataloged, and evaluated for traits like disease resistance and flowering time. Early data suggests the feral populations are more virus-resistant than modern commercial hemp—an unexpected bonus.
Ellison is also working with the Lac Courte Oreilles Ojibwe University in northern Wisconsin on dual-purpose breeding (fiber and grain), already achieving a 40% increase in seed size. That’s more than just an agronomic win—it’s a step toward food sovereignty, cultural restoration, and economic resilience in Indigenous communities.
She Collected 1,800 Seeds from Wild Cannabis—What She Found Could Rewrite Research on it
