Hemp Genetics: An Overview of a Rapidly-Evolving Field

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Image Source: Wikimedia Commons
July 22, 2020

Those who have farmed hemp in the U.S. in recent years are undoubtedly familiar with the uncertainty that accompanies buying seeds or clones to start a new crop. This post will summarize why genetics are important, how market participants and state agricultural officials are advancing knowledge, and some practical considerations for those looking to obtain seeds or clones to farm hemp. 

Why are Hemp Genetics Important?

As with other agricultural crops, the development of hemp varieties with stable and dependable genetics is of primary importance to the industry’s success. A plant’s genetics affect everything: from a crop’s germination rate to its harvest time, yield, hardiness, and, importantly for hemp, whether its THC levels will remain at or below the legal limit of 0.3%. 

While the above sentiments are widely recognized, determining whether the varieties on offer from hemp seed and clone sellers are as advertised can be difficult in a new industry. Farmers growing traditional crops – such as corn, soybeans, or wheat – know that they can rely on the specifications of a batch of seed being accurate in regard to its variety, germination rate, whether it contains noxious weeds, and other considerations. In traditional agriculture, such specifications are included on the label of a batch of seed. Seed labeling is subject to regulation and oversight by state and federal officials.

Unfortunately, this is not always the case with hemp, although the situation is changing. For example, Colorado has certified several hemp seed varieties to certain specifications in recent years. Still, this aspect of the industry is nascent. The U.S. Department of Agriculture’s (USDA) Interim Final Rule – the regulations currently governing hemp production in America – acknowledges that USDA did not include a hemp seed certification program in the measure “because the same seeds grown in different geographical locations and growing conditions can react differently.” It also admitted that “the technology necessary to determine seed planting results in different locations is not advanced enough at this time to make a [national] seed-certification scheme feasible.”

What Do We Know About Hemp Genetics?

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A study, “Mapping the cannabis genome to improve crops and health,” published in March and led by researchers at the University of Saskatchewan, says scientific understanding of the genetics of cannabis, the plant family of which hemp is a part, is still in its infancy. 

The study’s researchers reported that less than 50% of the cannabis genome has been mapped accurately. “Considering the importance of genomics in the development of any crop,” the study’s authors stated, “this analysis underlines the need for a coordinated effort to quantify the genetic and biochemical diversity of this species.” According to Tim Sharbel, a plant scientist at the University of Saskatchewan’s College of Agriculture and Bioresources, the lack of genetic information about cannabis “means that we lack the foundation on which to build a molecular breeding program for cannabis comparable to what exists for other crops.”

Market Demands Drive Breeding Innovations

In the absence of scientific knowledge of hemp genetics, those in the industry have forged ahead to develop commercially viable cultivars. According to Matthew Haddad, CEO and founder of Trilogene Seeds, a Colorado-based firm that specializes in the breeding and growing of hemp seed, breeders are constantly working to develop the more favored cannabinoids in hemp, as well as to adapt to new market demands. Terpene content, for example, has become an important factor in smokable hemp products, which were not in vogue widely until last year. 

“Traditionally a lot of hemp varieties kind of taste like hay,” Haddad said. “They don’t have the strongest terpene aromas like other forms of [high-THC] cannabis. So now we’re breeding for those characteristics, to make it a pleasurable smoking experience.”

In order to keep a finger on the pulse of the industry and be responsive to farmers’ needs, Trilogene is compiling their own database on hemp genetics by interfacing with those growing the company’s seeds and clones. Haddad said his company is working with roughly 500 hemp farmers around the world, who test out new seed varieties and provide feedback on their results. “We provide seed to them for free, and then we work with them throughout the year,” he noted. “They get first right of refusal the following year, along with aggressive discounts for working with us.”

Are Important Aspects of Hemp Genetics Being Overlooked?  

While the endeavors of companies such as Trilogene have resulted in notable developments in hemp genetics, some assert that a focus on cannabinoids has resulted in other important aspects of the crop being overlooked. Don Robison, Seed Administrator at the Office of the Indiana State Chemist (OISC), who is in charge of the state’s hemp program and enforcing seed laws for all crops, told Hemp Benchmarks that he believes the focus on CBD and THC levels in hemp has come at the expense of considerations such as overall plant vigor and germination rates. 

Robison began testing hemp seed germination rates in 2016 and found the results to be “all over the place,” fluctuating from as low as 20% to as high as 85%. His early research focused mainly on fiber varieties of hemp that he was able to source through Purdue University’s research lab. 

Since the passage of the 2018 Farm Bill, Robison has tested germination rates of about 150 different lots of seed of all different varieties – from CBD or CBG cultivars to those for fiber or grain – and reckons that OISC is “one of the top five” seed labs in the country in terms of the amount of hemp seed testing performed. He said that the more recent results still vary widely, and the average germination rate across all varieties tested was only 52%. Robison stated that in traditional agriculture, such a low germination rate would result in lawsuits from farmers. 

What Can Growers Do to Protect Themselves? 

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To help cut down on some of the uncertainty that comes with growing hemp, Robison advises those purchasing seed to consult its official label. (OISC has published a document, “How to Read a Seed Label.”) If the label claims a germination rate of above 80%, Robison recommends asking the seller for the report from the seed lab that did the testing, calling the lab, and confirming that the information on the label is accurate. 

If the lab can verify the label’s contents match with the lot number and date of testing, it should provide the buyer with some peace of mind. While some bad actors have falsified seed labels, Robison said that most will not go so far as to do that. 

Some hemp farmers that have had bad experiences growing from seed are looking to clones, but that can come with its own risks. Haddad, of Trilogene, noted that clones can carry the possibility of being infected with harmful pathogens such as powdery mildew, as they are often passed around amongst different growers and facilities. However, those looking to grow for CBD or other cannabinoids may prefer clones due to the fact that they do not typically have to worry about male plants, which can be an issue if seed is not actually feminized as claimed.

Robison also pointed out that, in Indiana, clone sellers do not have to obtain a permit from OISC, as seed sellers do, and his agency does not regulate the production and sale of clones in the state. He told Hemp Benchmarks that some Indiana farmers have had bad experiences growing from clones as well, but could not say whether such instances were more or less prevalent than with those growing from seed.   

Looking Forward to Stable Hemp Genetics

Like so many aspects of this new industry, more research is needed, a gap that market participants, academics, and agricultural officials are working to close. Robison told Hemp Benchmarks that OISC is currently collaborating with other seed labs across the country, testing germination rates of hemp seed available to farmers. He also noted that officials in every state, as well as Native American Tribes and U.S. territories, are networking to share what they are learning. 

When it comes to how many generations of breeding are needed to create hemp varieties with stable genetics, though, “we honestly don’t know,” said Trilogene Seeds’ Haddad, “because there are so many different environments, so many different cultivation methodologies.”

Hemp Industries Association Midwest Hemp Council National Hemp Association