Researchers at the University of Minnesota have validated a genetic test capable of predicting whether a cannabis sativa plant will produce predominantly CBD or THC.
The team examined three distinct plant varieties, comparing genetic markers against the ratio of THC to CBD, and confirmed that genetics reliably predicted that ratio.
Cannabis plants are currently classified as hemp or marijuana based on THC levels alone, but the researchers contend that definition does not reflect the underlying biology. In its place, they propose using the THC-to-CBD ratio as the basis for distinguishing THC-type plants from CBD-type plants.
Research lead George Weiblen said: "We validated a simple genetic test that can predict whether a plant will produce mostly the CBD or THC molecule, using a variety of cannabis sativa plants."
Understanding the genetic basis for CBD-type and THC-type plants carries significant implications for the US Department of Agriculture and state industrial hemp programs. The ability to identify CBD-type seeds before planting could allow for certification processes that guarantee consistency and quality.
Industrial hemp growers currently monitor cannabis sativa plants throughout the season and submit samples for chemical analysis, but THC levels peak at maturity and can catch growers off guard. Crops that exceed federal THC thresholds must be destroyed, making industrial hemp considerably riskier to grow than other crops.
"We hope this new test can assist in new seed certification for the hemp industry," said Weiblen.
"For hemp to take off in Minnesota and elsewhere, there must be ways to assure growers they won't have to destroy their crops at the end of the season."
The research team, led by the Weiblen Lab, published their findings in the American Journal of Botany.