Science of Industrial Hemp: On the Leading Edge of a Growing Industry

Photo courtesy of Purdue University. Industrial hemp is a cultivar of the Cannabis sativa plant and falls under stricter regulations than most crops. However, those working with industrial hemp see the crop as an opportunity to be on the leading edge of research in a growing industry. CSSA and ASA recently sponsored a conference on The Science of Industrial Hemp in Denver, CO in July, bringing together almost 200 researchers, producers, and policymakers interested in industrial hemp from more than 34 states and five countries. Based on the needs related to industrial hemp production discussed and clarified at the conference, organizers are in the process of writing a paper which will soon be published and presented on Capitol Hill. Several of the conference speakers shared information about the work they presented and their experience at the conference with CSA News magazine. The genetic distinctions between hemp and marijuana, both cultivars of C. sativa, are not well understood. The trait of concern for the DEA is that marijuana plants have high concentrations of THCA (tetrahydrocannabinolic acid), which is converted into psychoactive THC, whereas hemp has high concentrations of CBDA (cannabidiolic acid), which is converted into non-psychoactive CBD. Industrial hemp is defined as plants that are less than 0.3% THC by weight, so determining which genes control THCA and CBDA would be useful for screening, breeding, and developing hemp cultivars for the industry. New research from Dr. George Weiblen at the University of Minnesota suggests that the difference between cultivars may be determined by what is essentially a single gene with a major impact. In a paper published in New Phytologist, Weiblen and colleagues examined the genetic differences between hemp and marijuana. Much of the earlier genetic work has focused on the loci relating to THCA. But for this study, Weiblen and colleagues looked at both THCA synthase and CBDA synthase. “What our work suggests is that, in fact, it's this other, related gene that explains the difference in drug content between hemp cultivars and marijuana cultivars. That was a huge surprise—totally unexpected,” Weiblen says. Their findings show plants that are homozygous for functional CBDA synthase meet the definition of industrial hemp and lack the ability to produce more THC than the 0.3% threshold. The paper also reports that plants with at least one copy of the non-functional CBDA synthase allele will produce THC in quantities over 0.3%. This genetic distinction could lead to the development of a new way to screen seeds and plants. But first, Weiblen cautions, “Others need to verify our predictions.” Attending The Science of Industrial Hemp Conference, Weiblen was able to interact with individuals associated with, “basic research, industry perspective, policy perspective, and activists.” And he says, “It's really very interesting to see where those different perspectives intersect—where they have common ground but also very strong differences.” Certified seed sources are important for many crops, including grains, grasses, and soybeans. Certification processes were established in 1919 to ensure genetics and varietal integrity of the seeds farmers were planting. “Certified seed is a verification of the seed source, the growing process in the field, and finally, the analysis of the final product—the seed that's going to be marketed,” says Rick Novak, Extension Seed Specialist and Director of Seed Programs at Colorado State University. “The whole goal that we have is to provide a quality product.” Novak has been working on seed production for more than 30 years and says hemp is the perfect example of why certified seed is needed. “[Producers] don't want to be growing plants that have a chance or tendency to have levels of THC that are above the standards that are set forth by the federal and the state [governments].” But growing certified industrial hemp seed has its challenges. “The hemp plant is a very aggressive out-crosser,” Novak says. “So the pollen is very light and there is a lot of it. It moves quite readily from plant to plant.” With this high potential for out-crossing, isolation distances for certified seed range from ∼650 ft to more than 3,000 ft depending upon the crops grown nearby (distances for Registered and Foundation seeds are up to 16,000 ft). These distances are greater than many other certified seeds. For example, alfalfa has a minimum isolation distance of 165 ft, and in Colorado, certified grass seed isolation distances range from 15 to 165 ft. Hemp seeds. Photo courtesy of University of Kentucky College of Agriculture Although hemp research in the U.S. has been limited since the 1930s, Novak and his colleagues benefit from research from other countries that produce industrial hemp. “The information, or the processes that we use, we're adapting what's been used in Canada [and Europe] for maintaining genetic purity.” Novak also points out that working with this new crop brings people from different facets of the industry together. “We're all working together. Certification agencies along with growers to be good stewards.” Attending the conference, Novak was able to interact with people who are knowledgeable about different aspects of industrial hemp, including fellow researchers and growers. Although many hemp researchers feel that there is not enough research on hemp, by being together for a conference Novak realized “collectively there's a very large wealth of information.” And, as a member of the organizational committee, he says, “It's pretty exciting because what we're trying to do is bring science together so research can be somewhat unified and not duplicated.” Planting hemp. Photo courtesy of University of Kentucky College of Agriculture Purdue researchers Janna Beckerman and Ron Turco in a hemp test plot. Purdue Agricultural Communication photo/Tom Campbell. A greenhouse trial confirming hemp pathogenicity with a Pythium. Photo courtesy of Janna Beckerman. As the industry develops, and more hemp is grown across the U.S., hemp will face the same challenges as other crops. Dr. Janna Beckerman, a professor at Purdue University, says “This [is] actually a problem with hemp because if you read all of the literature, everybody says that it's this wonderful, disease-resistant plant that has no pest problems. [But] every living thing has disease and insect problems.” Beckerman's hemp research started about two years ago. “We've had problems both years—there's a learning curve involved for planting it out in the field.” But they have been successful in finding pathogens, having two very wet years in Indiana. “We had no problem finding diseases,” she says. There was also the problem of sourcing seed to establish this research project. “There were no seeds available to purchase in the United States,” Beckerman says, so she had to source seeds from Canada. Using seeds from Canada has shown the need for developing locally adapted varieties of hemp. “[These varieties] might work fine in northern regions of the U.S. but [are] not well-adapted here in Indiana.” And Beckerman would anticipate poor performance further south as well. Ultimately, Beckerman hopes to understand what pathogens and pests hemp plants are susceptible to, under what conditions these problems are likely to develop, and the best practices for controlling them. Part of this process would involve pesticide registration, which takes time for any new crop, “It's not anything that's unique to hemp.” However, the strict hemp regulations are likely limiting the research and development of new products. As with any conference experience, attendees like Beckerman were able to discuss the ups and downs of their research. “The problems that we had are very similar to the problems that they were experiencing in Colorado State and other universities involved in trying to do hemp research.” She also appreciated the opportunity to talk directly with growers and for everyone in attendance to realize that there are a lot of scientific and logistical hurdles in their future. “You don't just get the seed to plant it and develop a supply chain. I think making people aware that the supply chain didn't exist was really important.”

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