A recent study shows that high-CBD hemp plants get about 90 percent of their genes from THC-rich cannabis, meaning there is even less of a difference between the two types than previously believed.
The genomics research was carried out by the University of Minnesota and the hemp breeding company Sunrise Genetics, which was compiled and published by the online academic journal New Phytologist in the beginning of February.
In the study, researchers reviewed different varieties of cannabis and compared genomes between the types. The results showed that, while breeding high-THC plants with low-THC plants can breed high-CBD hemp plants, this can be risky, as the THC can still be present in future generations.
“The genes that allow for the production of CBD are also a bit ‘leaky,’” said CJ Schwartz of Sunrise Genetics. “This can result in about five percent of the product ending up as THC instead of 100 percent CBD.” In other words, it is possible for a cannabis plant that is meant to be high-CBD and have virtually no THC to cross the 0.3 percent limit.
“These high-CBD plants are genetically marijuana for the most part and they can’t be expected to meet the legal definition of industrial hemp in every situation,” said George Weiblen, one of the study’s co-authors. “This means that CBD products—such as flowers, extracts and edibles—that are labeled ‘hemp’ could be incorrectly labeled and falsely branded. Fiber hemp and products made from hemp seeds, however, are drug-free.Weiblam and his team made headlines last year when they came up with a genetic test that can predict whether a cannabis plant will produce mostly CBD or THC molecules. This test could come in handy for farmers working to ensure that the hemp they grow isn’t higher than the legal limit.