A hop crop showing the mature female cones just prior to harvest. Glands at the base of each individual cone scale produce compounds that contribute bitterness to beer, which balances sweetness created by the fermentation of barley malt.
Last November, I spoke at a national marijuana conference in Las Vegas, Nev., sponsored by Marijuana Business Daily magazine. The conference came on the heels of the fall elections, when Alaska, Oregon and Washington D.C. joined Colorado and Washington in legalizing cannabis for recreational use. Florida narrowly defeated its ballot measure to legalize medical marijuana. Twenty-one states have legalized already, and more are discussing the legalization question with each election cycle.
The focus of this article is not whether we should or should not legalize marijuana. Rather, it is to explain what many of us in the research and commercial sectors of horticulture are intrigued by, which is this plant’s botanical background, horticultural significance and controlled environment production potential.
Think OFA, BPI In The 70s
A number of us remember the early 80s when OFA and Bedding Plants International (BPI) emerged as national associations with their respective conferences and membership rosters growing faster than convention centers could expand. It was a period that can arguably be described as our glory days.
The welcome address at the marijuana conference included the fact that attendance has grown from 300 to 800 to 3,000 in its short, three-year history. Anyone remember being a part of this kind of growth? How about the excitement we felt, the energy in the trade show and the amazing education that was available?
I sensed all of this and then some during the three-day event. Kudos to the organizers — it was professionally run. The trade show was identical to what I’m used to experiencing, even with a number of familiar vendors from Cultivate. As a speaker and program organizer, my eye always focuses on behind-the-scenes activity. I was impressed by the quality of speakers and professionalism with which session facilitators and room monitors conducted their business. There were more speakers in jackets and ties than I’ve seen at our conferences in many years. And talk about the money represented by attending investors — too much and too many to count. When you hear that there is a ton of money waiting on the sidelines to invest in marijuana, believe it.
Think Poinsettias, With A Profit
Cannabis is a short-day plant, practically indistinguishable from a poinsettia. Growers of both crops are familiar with the long-day requirement during the early weeks of a crop cycle to allow the plant to grow vegetatively. Once a sufficient foundation has been laid, short days are provided to initiate and then develop reproductive growth.
A difference between these two crops is that poinsettia is harvested (sold) with fully developed flowers, whereas marijuana is harvested prior to flowering. It’s the mature bud and not yet open inflorescence that provides the crop value.
Hops, A Cannabis Cousin
A second difference between poinsettia and cannabis is a basic botanical one. The majority of plant species with horticultural value, particularly those grown for their fruit and other reproductive organs, are monoecious, meaning they produce both male and female flowers on the same plant.
Marijuana and a closely related crop species, hops, belong to a second group known as dioecious plants, where male and female flowers are not produced on the same plant. Instead, species in this group have separate male and female plants all together. A familiar nursery shrub, holly, also belongs to this group. Homeowners desiring red berries are instructed to include at least one male plant among the females to provide pollen to fertilize flowers and allow fruiting to take place.
Both marijuana and hops are grown for their high levels of uncommon oils and other organic compounds produced in their female flower buds. These compounds contribute flavors and aromas that have been valued by humans dating back to our earliest records of civilization. The culture of both crops is focused on growing only female plants in order to maximize yield. Flower fertilization and subsequent seed production are not desired on plants grown for harvest. Male plants are significant only in breeding, when flower fertilization is desired to produce seed for the next generation of new cultivars.
Genes Versus Environment
My presentation to the cannabis-centric audience focused on the similarities between its emergence and other prominent horticultural crops. Poinsettia and apple were used as examples to describe how these crops were taken from relative obscurity to category leader status as a result of breeding and research.
This premise dates back to a plant anatomy course I took in graduate school, taught by a wise old botany professor. His semester-long message was that a plant is a product of its genes and environment. Whenever my classmates and I would confidently state that a plant would respond in a certain way because of its genetic skeleton, he would hang us out to dry by citing how an environmental factor could override the genes. Reciprocally, whenever we would state that specific greenhouse conditions would guarantee a certain crop response, he would saw off the branch we stood on by citing how the crop’s genes could override the environmental factor. The smart students caught on quickly. Not sure where I fell, but I swear by his rule four decades later.
Modern poinsettia history pivots in the early 1970s. Prior to this period, cultivars did not branch, grew tall and dropped leaves freely. Single stem plants were the norm and an ingenious technique known as stem folding attempted to address height control. Yes, the hollow stem was actually pinched in two places, folded on itself and tied to reduce plant height.
The Annette Hegg breeding breakthrough changed everything. Cultivars branched freely after a hand pinch, grew wider and shorter as a result and retained leaves longer after leaving the greenhouse.
Once this genetic advancement was made, all areas of production were researched to figure out how the environment could be manipulated to maximize the new genetic potential. Nutrition, temperature, light, chemical growth regulators, pest management and postharvest care and handling received significant attention from researchers. The result was a trajectory for poinsettia that propelled it to its status of our country’s number one flowering potted plant for decades.
Apple production has also benefited from the genes and environment rule. Today’s apple tree is anything but a large, umbrella-shaped tree that requires ladder-assisted harvest. Breeders have shaped today’s tree into a smaller, manageable plant that grows more like a grapevine than a fifteen-foot-tall tree with a 20-foot spread.
Research turned apple culture on its ear by changing the environment that the new genetics supported. Tree density increased to fit many smaller trees on an acre with significant increases in production. And while breeders delivered dwarf plants, these trees still need to be trained along their trellises.
Transformational Breeding
As marijuana production evolves from an illegal underground hobby to a legal and visible industry, most of the common production practices will be researched and evaluated from a scientific perspective. Indoor lighting, irrigation and nutrition, pest management and the breeding of new cultivars are a few of the areas that will receive more attention.
Cannabis is poised for transformational breeding advancement, just like poinsettia and apple. To date, most of the breeding has focused on postharvest characteristics, or the specific mood desired with consumption. I predict that breeders will soon focus on production characteristics including branching, height, flowering and yield, which will catapult the crop to national status.