Around the world people are coming to grips with the health issues and economic fallout of COVID-19. Public awareness of viral contagions is reaching unprecedented levels, presenting an opportune moment to address disease problems within the cannabis industry. As we are seeing with the novel coronavirus pandemic, harmful viruses emerge and adapt, and this is not exclusive to humans. Cannabis growers are increasingly experiencing the negative economic outcomes of decreased vigor, lower flower yields and reduced production of primary target compounds including both cannabinoids and terpenoids. What we are calling “Cannabis disease syndrome (CDS)” exhibits a suite of consistent symptoms, but with no readily apparent single cause. These symptoms, which do not appear to be caused by nutrient deficiencies or other pathogens, are often collectively referred to as “dudding” or “dudders.” (The term originated when growers would think a plant with decreased vigor or stunted growth was “just a dud.”)

Steadily declining vigor in commercial Cannabis clones is not a new phenomenon. As vegetative reproduction by rooting cuttings became popular in the 1980s, growers would occasionally see a clone that became weaker and less productive each time cuttings were flowered. Apart from lowered yield, there were few other symptoms of infection. We tentatively called this a “photocopy effect” based on our analogy that copying a copy of a copy of a copy, results in a faded image that eventually becomes a mere ghost of the original.

We knew that because lost vigor was appearing in asexually multiplied serial cuttings the problem could not be explained by “genetic drift,” which is a shift in the frequency of genes within a small sexually reproducing population. Growers wondered what the causes might be, and even addressed the possibility that simply making serial cuttings might result in diminished vigor.

Soon we realized the symptoms were caused by transmission of an infectious disease that became more and more prevalent through successive rounds of multiplication. (More on this later.) We destroyed clones exhibiting symptoms, carefully sterilized benches, pots and tools, and began to use fresh blades when taking cuttings from each mother plant. There were no known causes, just obvious adverse effects. Yet we found practical solutions, and soon the problem nearly disappeared.

Some similarities exist between the CDS we are experiencing today and COVID-19. Much like the human coronavirus, CDS is difficult to detect at first, as there is a wide range of symptoms. Through our and other growers’ observations of affected plants during the past few years, we have learned that vegetative plants can transmit CDS, while flowering plants are more likely to suffer the consequences. Because symptoms are not readily visible and are easily confused with other diseases, they both lie hidden within populations, and can very quickly become economically impactful. Another similarity between CDS and COVID-19 is that asymptomatic plants can infect the otherwise healthy, with more serious outcomes for some than others. Molecular testing is required to identify potential infections, and there are few laboratories that can effectively identify the causal organisms. Other than practicing social distancing and establishing quarantines, there are as yet no solutions to stopping their spread.

Cannabis disease syndrome cannot be attributed to a single pathogen, although there is a primary candidate for its cause (more on this later). In symptomatic plants, several infectious organisms may be involved, making accurate diagnosis and effective control even more difficult. If CDS killed more of its hosts rather than simply making them sick, then it would have been noticed much earlier, and should not have already spread so widely. As we also have observed while studying affected plants, the cannabis disease syndrome spreads most quickly by taking cuttings from infected plants, using them as mother plants, and thereby multiplying the disease through future generations.

What causes CDS?

In the Spring of 2019, two laboratories independently identified hop latent viroid (HpLVd) within a number of California sinsemilla clones, and this pathogen is the prime suspect in our search for the causal pathogen of the CDS we experience today. Originally discovered in Cannabis’s closest relative Humulus lupulus, the source of hops cones used in brewing beer, it is unclear how it spread to Cannabis. Unlike viruses and other diseases with more readily apparent symptoms, HpLVd is symptomless in most hop cultivars, affecting only the most susceptible. And, co-infection is often first indicated by the symptoms of opportunistic fungal pathogens that infect hop plants weakened by HpLVd, or plants weakened by HpLVd may become more susceptible to fungal or bacterial diseases, similar to the situation we face in diagnosing its infection of Cannabis.

How can we know if our plants have CDS?

Infected plants vary from the healthy norm. CDS symptoms are subtle and difficult to perceive and are therefore most noticeable in clones with which a grower has intimate familiarity. The foremost outcome of a CDS infection is lowered productivity resulting from a loss of vigor. Plants grow more slowly, flowers are smaller, and resin gland development is slowed. Lower branches appear to grow away from the central stalk more than usual and sag, while the main stem grows erect. Other common symptoms include brittle stems that easily break when bent, distorted leaf growth, variegated and chlorotic leaves and overall stunted growth, resulting in drastically lowered expression of terpenes and cannabinoids.

Although the presence of HpLVd may initially be asymptomatic, as it progresses, additional symptoms begin to appear such as stunted growth, general yellowing of the foliage, discolored mosaic blotches or streaks, interveinal yellowing, deformed leaf margins of younger leaves and discoloration within the stems, all characteristic symptoms of possible opportunistic coinfection by fungal or bacterial pathogens.

Adding more confusion, HpLVd-infected plants may actually exhibit symptoms that can be perceived as favorable, such as darker green foliage and increased branching, which complicates detection and control while increasing its spread through the propagation of seemingly healthy cuttings. Molecular testing by experienced laboratories is the only way to verify the presence of HpLVd.

Viral infections spread internally from infected to clean parts of the same plant, making sampling difficult. Only part of a plant might be infected, maybe just one or a few limbs. Since HpLVd may hide in a minute portion of the vascular system, the only way to know for certain that a plant is healthy is to test tissues from several parts of the plant before destroying it. Sampling each clone for pathogens, and verifying that the cutting remains clean, can be a costly process.

How can we control CDS?

Long before scientists discovered that a human immunodeficiency virus (HIV) is the primary cause of acquired immune deficiency syndrome (or AIDS), health care organizations were already advising people of preventative measures: use condoms, do not reuse needles, sterilize razors, etc. They understood the severity of AIDS and how to curtail its spread long before they knew its cause. As with human viruses, awareness, mitigation and suppression are the key elements in the control of plant pathogens. Once awareness is raised throughout our community, testing must begin to learn the causes of the disease and the extent to which it has spread. Infections must be traced back to their sources, and diseased plants either quarantined or destroyed. If the spread of CDS is stopped, it may eventually die out, or at least reach levels that do not cause widespread economic losses. There are several steps that growers should take to prevent the spread of pathogenic diseases in general, and specifically CDS.

1. Control pests.

Viral vectors include common Cannabis pests such as aphids, whiteflies, thrips and mites that transmit and widely spread viruses and other pathogens by first feeding on an infected plant, and then feeding on an uninfected plant. Effective pest control should be a part of every grower’s strategy.

2. Keep it clean.

Each time you take a cutting, the plant’s vascular system is susceptible to infection. When establishing new mother plants, use fresh, sterile blades directly from the package or use sterilized scissors for every cut to assure you are not transmitting a disease. Viral and fungal infections can also spread via contaminated containers, benches and growing media. Household bleach diluted with five parts water is an inexpensive and effective sterilizer. Spray clean tools, soak scissors, drench containers and wipe down benches. Use sterile media for rooting cuttings and growing flowers. Wash and sterilize your hands or change gloves before moving on to the next mother plant. When possible, buy clean stock from a trusted nursery.

3. Quarantine.

Set up a sterile quarantine area for any new arrivals to your facility, and keep new additions isolated within until you become confident that they are not infected. (Again, the only way to be entirely sure a plant is healthy is testing.) Flower a few cuttings in isolation and watch for disease symptoms before multiplying your mother plants. Better yet, do not accept any foreign plants. As we have observed time and again, most grows become infected by taking in cuttings from others.

4. Limit visits.

An infected plant can touch an uninfected neighbor and spread diseases, and humans who come into contact with infected plants can also spread diseases. Prevent the spread of CDS by keeping people who may have been in contact with potentially infected plants, especially other growers, out of your quarantine and propagation areas.

5. Destroy affected plants.

The easiest, cheapest and most effective strategy is to destroy any mother plants you suspect are infected. Always label and number cuttings so you will know which mother they came from, then later each cutting can be traced back to its source. Should cuttings prove to be infected you should destroy the entire clone—the mother plants and all of their cuttings.

Can I get rid of CDS?

Once CDS is suspected and/or confirmed in a crop there are several possible solutions for its control.

1. Outgrow it.

Viral and fungal infections translocate through the vascular system of the plant and may be left behind in older tissues as plants develop, so it may be possible to simply outgrow the problem. Under vegetative daylength (more than 16 hours of light each day), transplant small mother cuttings into fresh sterile media, feed them well, and grow them rapidly under strong artificial lighting, or better yet, under full natural sunlight. Take small cuttings from the uppermost meristems or growing tips of the fastest growing plants and root them in sterile media or an air rooter with sterile water. The more cuttings a grower roots, the higher the chances of selecting a clean one.

Unfortunately, many of society’s most popular clones, some of which have become industry standards, have the highest chance of being infected. By now they have been through countless vegetative propagation cycles, and each cycle exposed them to possible infection. Whenever feasible, replace potentially infected cuttings with an earlier version of the same clone. Smaller growers who focus on fewer varieties may have started with and still maintain an uninfected clone. Quarantine any new arrival and be sure it performs better before replacing your old favorite.

There are other possible solutions that should be outsourced unless a grower has the resources to try them on their own. Micropropagation of meristems in vitro has been touted as a way to clean an infected clone. Many confuse micropropagation with in vitro culture of callus or undifferentiated cells, the plant version of stem cells. Meristems are the last place pathogens reach as they spread through a plant, and the smaller the cutting, the less chance it will be infected. Micropropagation protocols root tiny meristems in sterile conditions, much smaller cuttings than can be rooted in a typical commercial nursery. Once a clean clone is maintained in sterile culture it remains clean, and when multiplied under sterile conditions its offspring will also be clean.

Micropropagation alone does not remove pathogens. However, nurseries are developing protocols to reduce and possibly eliminate pathogen loads by passing meristems through a series of conditions that kill disease organisms without killing the plant. Although theoretically possible, no company has shown that this process actually works, and results in a disease-free plant that also retains its favorable characteristics. One can only know if cleanup has been effective by first testing to be sure a pathogen such as HpLVd is present before treatment, and then cannot be detected following treatment. A clone that has been “cleaned” should also exhibit the favorable traits it had before it became infected. Before spending money, one must decide whether their clone is worth attempting to recover, or whether it would be more efficient to restart with clean nursery stock or seeds.

2. Sow your seeds.

Unsanitary cuttings are the main root of Cannabis diseases, and rather than trying to clean an infected clone, growers can simply sow seeds. Seed and pollen transmissions of viruses and viroids have been shown for several crops but are unconfirmed in Cannabis. Traditional seed propagation interrupts a pathogen’s life cycle, allowing a fresh start each year. Seeds provide the best chance of procuring clean plants and establishing a new clone. Who knows? You might even discover the next OG Kush!

Conclusion

CDS rarely kills individual plants, which is one reason for its silent spread, but it may well be lethal to our industry. We have no measure of how fast it is spreading. We are only beginning to examine the problem, and as our awareness increases and growers begin to experiment, more effective solutions will certainly appear. As cannabis is increasingly commercialized, disease control will become the responsibility of licensed and certified nurseries that will preserve and distribute clean stock, like all clonally based commercial agriculture from potatoes to berries.

It is high time for our industry to be proactive. CDS as well as other diseases have become part of our industry and are likely here to stay. As with viruses within our human population, we will learn how to live with them and manage them efficiently.

Robert C. Clarke is a freelance writer, photographer, ethnobotanist, plant breeder, textile collector and co-founder of BioAgronomics Group Consultants, specializing in smoothing the transition to a wholly legal and normalized cannabis market. info@bioagronomics.com

Mojave Richmond is the developer of many award-winning varieties such as S.A.G.E., which served as a springboard for creating many notable cultivars. Richmond is a founding member of the international consulting company BioAgronomics Group. info@bioagronomics.com

Ali Bektas is an Istanbul native who received his Ph.D. from University of California, Berkeley where he worked on field-based DNA detection methods for indigenous farmers in Mexico to monitor local corn landraces against transgenic contamination. He was staff scientist at Phylos Bioscience from 2017 to 2019.

Hop-forward beers with complex aromas are sweeping the market. Pioneered by innovative North American craft brewers, many of the major breweries have been quick to add India Pale Ales (IPAs)—beers traditionally recognized for their hoppy bitterness—to their expanding product lines. Modern-day IPAs and other craft beers are increasingly hopped with aromatic cultivars that impart their characteristic bitterness to beer and also express fruity, floral and herbal terpene aromas and flavors resembling those of cannabis flowers. The relationship between buds and suds are often enjoyed in social settings, and the enhanced effects of consuming hoppy beers are often discussed on beer blogs. Is exploring the heightened effects of consuming hoppy beer and terpy cannabis together the natural next step?

Smoking and drinking in moderation go hand-in-hand, as any bar owner will attest. Many people relax after work with a smoke and a beer. So, what could be so special about using cannabis and drinking terpy beer compared to regular beer? Isn’t it just about the THC and ethanol?

Hop and Hemp

Humulus and Cannabis are each other’s closest botanical relatives. Female Humulus lupulus, or common hop plants, are commercially grown to produce the flowers called “hops,” which are most often dried and used in brewing beer. Hops are grown seedless to encourage the production of bitter alpha-acids and the aromatic terpenes important in brewing, much as cannabis flowers are grown seedless to encourage the production of cannabinoids and terpenes. Seeds only add to the weight, which increases the cost of the hops, while diminishing the target compound contents. And oily seeds are no more desirable in beer than they are in sinsemilla flowers.

OK, so Cannabis and hops are related. Why would consuming one enhance the effects of the other? The simple answer is that they both contain similar suites of aromatic terpenes. Only Cannabis plants produce cannabinoids (e.g., THC and CBD), while both Cannabis and hops produce a wide range of the same aromatic terpene compounds. The characteristic compounds found in hops that account for the bitter taste of beer are alpha-acids, especially humulone, which is absent from Cannabis. Humulone should not be confused with the terpene humulene, which is commonly found in both Humulus and Cannabis flowers. These closely related plant groups evolved from a common ancestor, and it is instructive to compare the aromatic contents of Cannabis essential oil to that of its near relative, and to understand which terpenes and other aromatic compounds are also shared by Humulus. (See the “A Closer Look: Terpenes in Cannabis and Hops” box below.)

Myrcene is the predominate terpene found in both Cannabis and Humulus and can make up more than three-quarters of the terpene content in some samples. Caryophyllene and the farnesenes are also found in high concentrations in both hemp and hops. Pinene is prevalent in Cannabis, while humulene is prevalent in Humulus and is one of the terpenes preferred by brewers. Limonene is a major Cannabis terpene, occasionally exceeding myrcene levels, and along with terpinolene, ocimene, carene and the phellandrenes, can have a major presence in Cannabis but usually only a minor presence in Humulus. On the other hand, bisabolenes, selinene, bergamotene, aromadendrene and spathulenol are more common in Humulus and only appear in smaller amounts in Cannabis. Brewer’s hops are usually myrcene and humulene dominant with the remaining terpenes found in much smaller amounts, and Humulus does not produce such a complex array of terpenes as Cannabis.

Without hops, beer is mostly fermented barley mash, water and ethyl alcohol. Ethanol is essentially a one-dimensional drug with limited variation of effect. The aromatic constituents of hops add a vivid spectrum to the basic shades-of-gray palette provided by alcohol alone. Sinsemilla contains predominately THC, a single psychoactive compound, as well, but supported by a wide range of aromatic terpene compounds that modify the effects of THC alone. Although Cannabis and Humulus plants share several common terpenes, others occur in both more rarely, and some are produced by only one genus or the other. Possibly cannabis adds to hoppy beer a broader spectrum of terpenes and thereby enhances a more well-rounded and complete experience. Terpenes may also create an olfactory bridge between the effects of consuming cannabis and the effects of drinking beer. The aromas common to both sinsemilla and hop flowers enhance the blending of these pleasurable experiences. In addition, subtle psychoactive effects induced by individual terpenes and aromatic blends may enhance the combined experience.

Historical Hops

Hops have long been associated with adding special properties to beers. “The Hop Farmer: A Complete Account of Hop Culture,” written in 1838 by agricultural writer E. J. Lance, informs us of the psychoactive potential of hoppy ales: “It is the opinion of brewers that the intoxicating qualities of ale are to be partly ascribed to the oil of the hop. … As a narcotic its powers are known in beer, and have been often used to produce sleep from the smell only … .”

Among beer lovers, the effects of hops are increasingly discussed. A brief survey of beer blogs discovered several effects attributed to hop-forward craft beers—especially those brewed with the particularly aromatic American hop varieties—including more vivid dreams, euphoric happiness and sedation.

Lance also writes that Georgian- and early-Victorian-era hops were smoked for their flavorful terpene content as well as their medicinal effects: “In a productive year any means of using up the hops will be of service to the growers, it is therefore recommended to be smoked instead of tobacco, or it may be mixed therewith; it is grateful to the taste and smell, and moreover will cure rheumatic pains by using in this way.”

These observations add credibility to the hypothesis that drinking hoppy beers can produce subtle effects above and beyond those from alcohol, and that an abundance of aromatic hops can enhance the experience of drinking beer.

Craft brewers have become increasingly transparent in their presentation of the hop and cannabis relationship. Some make subtle wink-wink, nudge-nudge allusions while more bold brewers leave no doubt where they stand. Hop Valley Brewing Company’s Bubble Stash IPA label encapsulates the cannabis persuasions of their intended customer base: “Our brewers reached into their secret stash of mosaic cryo hop resin to create a tropical dankness in this new age IPA. Take a hit of these bright sweet fruit notes in the easy drinkin’ bubbler. You won’t want to pass this one!”

Aromatic sinsemilla flowers and hoppy beers are a marketing match made in heaven. There are so many ways to present the relationships between both plants to the modern marketplace. We will surely see many innovative business models succeed. Our future is on our doorstep!

What’s All the Fuss About?

Regulated cannabis environments generally prohibit publicly smoking otherwise legal cannabis. Consumers can buy cannabis from a licensed retailer but must take their purchase off-premises to even open the package. Most hotels, bars and restaurants do not allow smoking, or any cannabis consumption for that matter. Smoking while driving is illegal, and street consumption is certainly uncool and can result in fines. So what are honest cannabis consumers to do?

Demand for mixed consumption venues is high. In several jurisdictions, strict adult-use laws segregating consumption of food and drink from smoking of any kind are yielding to mixed consumption venues where cannabis can be purchased on site and smoked in designated areas. We believe food, alcohol and cannabis consumption will begin to occupy the same commercial spaces. Given the reservations of policy makers toward smoking, it likely will be quite some time before permits are issued for mixed consumption venues—but we already see mixed consumption at conferences and concerts where food and alcohol are served and smoking is tolerated within defined areas. Co-consumption is what consumers want, and they usually get their way. As we always say, just follow the money! As profitable co-consumption business models begin to unfold, they will rapidly gain in popularity. It will soon become increasingly important to more extensively explore and understand the synergistic relationships between Cannabis and Humulus plants and their products.

We are just now learning how the numerous aromatic compounds synthesized by Cannabis plants help shape the effects associated with various cultivars. It would be naive to assume that the terpenes in cannabis products do not interact synergistically with foods and beverages, as well. Our as yet limited understanding of the “ensemble effect” among cannabinoids, terpenes and myriad other compounds contained in Cannabis plants is already opening the door to understanding the complex chemical interplay sculpting the effects achieved by using cannabis products. Although in comparison to cannabis consumption, terpenes may play a lesser role in shaping the inebriating effects of beer drinking, it would be equally naive to assume that they exert no effect at all.

Our preferences for various cannabis and hop aromas are rooted in our associations with other plants and our previous experiences. The sustained popularity of modern, highly aromatic “loud” cannabis and the proliferation of hoppy IPAs are strong testaments to the complex role plants and their various chemical constituents play in consumers’ lives. Understanding how certain aromatic compounds potentiate, modulate and regulate the actions and effects of other active ingredients and the influences of these effects on forming individual aroma preferences presents a mountain yet to climb.

Robert C. Clarke is a freelance writer, photographer, ethnobotanist, plant breeder, textile collector and co-founder of BioAgronomics Group, specializing in smoothing the transition to a wholly legal and normalized cannabis market. info@bioagronomics.com

Mojave Richmond is the developer of many award-winning varieties such as S.A.G.E., which served as a springboard for creating many notable cultivars. Richmond is a founding member of the international consulting company BioAgronomics Group.

Cultivar Details:

Plant physiology: Snake Eyes has relatively short internodal spacing, medium to broad purple leaves and finishes 3.5 to 4 feet tall if vegged for 3 weeks.

Average yield: Snake Eyes is a low yielder at around 0.07 lbs./sq. ft. of canopy.

Flowering time: Nine to 10 weeks

Ideal light-intensity setting: 600 to 700 micromoles (umols)

Ideal cultivation environment temperature: It likes moderate temperatures in the low- to mid-70s (Fahrenheit).

Ideal cultivation environment relative humidity: It likes moderate humidity in the 55% to 65% RH range.

Water needs: It’s a slow drinker. On-demand watering using a tensiometer would be the best way to feed her. Or you can track the daily feed volume and keep the runoff at 10% to 20% of saturation.

Nutrient needs: Snake Eyes feeds heavier in the stretch phase but normalizes its diet during the finishing stretch.

Cannabinoid profile: 21% to 24% THC, 1% CBG

Terpene profile: Top four (in order): B-caryophyllene, limonene, linalool, and B-myrcene

Susceptibility to diseases/conditions: Snake Eyes has some minor light sensitivity. Keeping light levels around the recommended 600 to 700 umols range should help cultivators avoid light burn.

David Holmes is founder/CEO of Clade⁹

The first time I really considered the problem of genetic diversity in commercial cannabis was in a policy discussion about some important goals for the cannabis community and industry. Among the proposed goals was something like “promote and enhance the genetic diversity of cannabis and avoid monoculture.”

A monoculture is a crop of a single type that is grown in a large area. In its most extreme form, a monoculture crop is not only of a single type (such as corn or potatoes) but is also substantially the same at the genetic level (such as all of the crop being russet potatoes or a certain variety of corn).

Before we get into the proposed goal of genetic diversity in cannabis, let’s examine monocultures. First, what is good about monoculturing?

The farmer has a very uniform crop that has been bred to be highly productive and predictable in how it’s farmed. Many things about agriculture are unpredictable—two big things being weather and market prices at harvest time—so it’s understandable that farmers want some predictability going into a growing season.

The limitation of a monoculture is that it’s a total commitment to one strategy. If a new virus or other pathogen reaches a monoculture crop that is susceptible to it, the entire crop is uniformly susceptible and can be wiped out. We are all living through the emergence of a new virus, so we know the outbreak of a new pathogen is something that really can happen. If our human population were a genetic monoculture highly susceptible to the new coronavirus, everyone would need to be in an intensive care unit. Fortunately, for every person who needs advanced treatment, there are many more who show no symptoms when infected; and others are somewhere between these extremes. This dynamic can also exist with crops—a genetic monoculture that is susceptible will be affected uniformly by a new pathogen, while a genetically diverse farm will have a more robust and varied response.

Historic examples of this problem include the Irish Potato Famine in the 19th Century, the “Panama disease” wipeout of the Gros Michel banana variety in the 1950s, and the southern corn leaf blight of 1970. In these cases, monocultured crops had no resistance to new pathogens, which spread widely and caused massive crop failures.

Another downfall of repeated monoculturing is its effect on the land and nearby habitat. Each crop has its own interaction with the soil and the organisms around it. In a sense, each crop takes something from the soil and some crops put something back into it. If, year after year, all the “taking” is of the same kind, then whatever is continuously taken can be depleted. This is a common problem of nitrogen-depleting crops that traditionally were rotated, in a given space, with nitrogen-replacing crops the following season. Nitrogen is essential for things like photosynthesis, protein production, and other vital aspects of plant health and productivity. In the absence of effective crop rotation, the soil can become critically low in nitrogen and unsuitable for farming.

In addition, the monoculture can affect nearby populations of insects, wildlife, soil microbes, etc. Some will thrive from positive interactions with the monoculture—to the point of a population explosion or other form of overgrowth—while others will dwindle because they do not interact well with that particular crop. The net effect is that a prolonged monoculture almost inevitably distorts the environment around it. For example, an analysis of more than 450 data sets and more than 50 insect species demonstrated that “variance in plant nutritive traits substantially reduces [insect] performance” and “increased [diversity] within agricultural crops could contribute to the sustainable control of insect pests in agroecosystems,” according to William C. Wetzel, lead author of the paper “Variability in plant nutrients reduces insect herbivore performance” published in the journal Nature in 2016.

How do farmers address these challenges so they can enjoy the benefits of a monoculture without the negative effects? Generally, they restore whatever the monoculture depletes with fertilizers or other supplements. They avoid the total wipeout from a pathogen or pest with pesticides or other chemicals created to prevent various kinds of pathologies.

The Founder Effect and Erroneous Assumptions

Back to the policy meeting. As we were discussing the need for biodiversity in cannabis, I pointed out the numerous varieties that are commercially available. I made the point that I have never seen a restaurant offering flights of different varieties of corn; however, when I go into a dispensary, I certainly see a wide selection of cannabis choices. While that is true, it is not the whole story.

Even though there are many different cannabis varieties, most of those that are commercially available have been developed from a relatively limited number of ancestors. When a large number of individuals all descend from a small number of ancestors, this is referred to as the “Founder Effect.”

Here is an easy way to visualize the Founder Effect: Think of the castaways stranded on Gilligan’s Island. Suppose the island had been very large with abundant resources, the castaways never left, and no one else ever came to the island. Instead, the original seven inhabitants had children, their children had children, and so on.

Many generations later, there could be millions of people on the island. But all those people would have the same ancestors. No matter how many branches in any family tree, the entire population of millions of people still would have no more genetic diversity than the original seven people, unless an occasional mutation occurred and was passed on to subsequent generations.

This example demonstrates the error in my thinking—assuming that, because there is a large number of individuals (or cannabis varieties), this means that there is proportionally great diversity within that large number. When a Founder Effect exists, that assumption is not accurate; and the Founder Effect is definitely present in most commercial cannabis.

This makes sense because prohibition limited what was available for people to breed with, and the desire for a certain effect was what people were breeding for. This is why most varieties of cannabis are dominated by THC and myrcene. Varieties with low THC or those with other terpenes present certainly exist; but such varieties are nowhere near as common, and they are more difficult to develop from the readily available gene pool. It may also explain why certain kinds of pathogens seem to pose problems for many or most varieties of cannabis—resistance genes that may exist in a wider gene pool are rare or absent due to the Founder Effect.

What we have in currently available cannabis varieties is a wonderful—but narrow—slice of a very large pie, genetically and chemically speaking. The genus Cannabis has the genetic potential to do so many things that we are not fully enjoying yet. For example, everyone knows about THC and CBD, and we may have heard some things about “minor” cannabinoids like CBG, THCV or others.

But it is still relatively difficult to find a cannabis variety in which something other than THC or CBD is the dominant cannabinoid, even though the genus has the capacity to make dozens or even perhaps hundreds of others. And it is still a relatively unusual variety that is low in myrcene and high in some other terpenes with different effects. When measured by cannabinoids or terpenes, currently available cannabis is far less diverse than it could be, which makes it more susceptible to diseases and pests.

Sources of Genetic Diversity

The future of the cannabis industry and of plant medicine lies in the rich diversity that exists in the many sources of genetics outside the Founder Effect. This is available in the seed collections gathered by some of the giants of our community, not all of whom are famous or yet recognized for their work. It is also available in landraces that exist all over the world. Renowned cannabis researcher and CBT contributor Robert Clarke described landraces as “varieties maintained by local farmers in concert with the natural selective pressures of the local environment. [They were] usually selected for a particular end use, whether it was for marijuana or for hemp seeds or hemp fiber,” in the 2016 article “Cannabis Conversations” published on ProjectCBD.org.

These seed collections, and the landraces or landrace hybrids that many of them contain, are sources of greater genetic diversity that represent a major value to the cannabis community, the cannabis industry, and the world as a whole.

In many cases, based on my conversations, they are eager to share the rich diversity within their collections. What they want and deserve is acknowledgment, some fair form of compensation for their life’s work and contributions, and a say in how their collections are used. By sharing their collections, they can promote diversity in cannabis and contribute to the development of new plant medicines.

Standing on Others’ Shoulders

Just as today’s plant breeders stand on the shoulders of the giants who came before, the seed collectors and other pioneers of our community stand on other shoulders—the communities of farmers and consumers of cannabis plants around the world; the many places and peoples from which came the various landraces. When we define an indigenous cannabis variety as a landrace, that can seem to imply something that naturally evolved and to which no person has a claim of ownership. This was also how many people thought of plant medicines found in rainforests or gleaned from the ancestral knowledge of indigenous peoples. The discipline of ethnobotany explores the traditional knowledge and customs of a people concerning plants and their medical, religious, or other uses. Ethnobotanists have studied and documented these practices, and that work has led to important advances in medicine.

As ethnobotany and other disciplines brought traditional knowledge and medicines into streams of global commerce, some of these medicines created value and intellectual property for pharmaceutical companies. Correspondingly, a new public awareness developed as to the ethics of this kind of value-creation. This was most fully codified in the Nagoya Protocol, which is part of the larger Convention on Biological Diversity. It is an important framework to ensure that—where value is created from local sources and/or traditional knowledge—a fair amount of that value ends up back at the source.

Thanks to the great genetic diversity available from landraces and private seed collections, the coming decades will bring major advances in plant medicines, according to Dr. Ethan Russo, who has been involved researching and developing medicines from cannabis and the effects of the endocannabinoid system in many capacities for decades. This genetic diversity will also bring into the available gene pool better resistance to pathogens and better overall agronomic properties. The global reach and significance of these advances will depend upon taking full advantage of the vast genetic potential and traditional knowledge that are available. This will overcome the genetic bottleneck of the Founder Effect, to the benefit of patients, users, and growers everywhere. And, if handled ethically, there will be significant collateral benefits to independent plant breeders and local communities worldwide.

Dr. Dale Hunt is the founder of Plant & Planet Law Firm, where he practices IP law in cannabis, agriculture, medicine, other life sciences. He also has a doctorate in molecular biology and a bachelor’s degree in botany.