Over the weeks, we’ve delved into every aspect of cannabis cultivation, from soil health to environmental controls and even the distinctions between cannabis and hemp. This week, we dive deeper into a subject that underpins every successful grow: genetics. Cannabis genetics is the blueprint that determines a plant’s traits, from its growth pattern and cannabinoid profile to its resistance to pests and environmental stressors.
By understanding and harnessing cannabis genetics, growers can unlock the full potential of their plants, tailoring cultivation to meet specific goals—whether it’s high THC content, abundant CBD, or robust yields. This blog explores the science of cannabis genetics, how to select the right strains for your setup, and how breeders develop stable, high-performing cultivars.
The Science of Cannabis Genetics
Cannabis genetics is rooted in the interaction of genotypes (a plant’s genetic code) and phenotypes (observable traits expressed under specific environmental conditions). Every cannabis plant’s phenotype is a combination of inherited genetics and environmental factors such as light, temperature, and nutrient availability.
For example, two plants with the same genetic makeup may express differently when grown in distinct environments—one may grow taller with a citrusy aroma, while the other remains short with earthy undertones. This variability is why choosing the right genetics is critical for growers seeking consistency.
When it comes to Cannabinoid Expression
Cannabinoids such as THC (tetrahydrocannabinol) and CBD (cannabidiol) are among the most studied compounds in cannabis. Their production is controlled by enzymes encoded by specific genes:
THCA Synthase (THCAS): This enzyme converts cannabigerolic acid (CBGA) into tetrahydrocannabinolic acid (THCA), the precursor to THC. Variations in the THCAS gene dictate the potency of THC-dominant strains.
CBDA Synthase (CBDAS): Similarly, this enzyme converts CBGA into cannabidiolic acid (CBDA), the precursor to CBD. Plants with dominant CBDAS activity produce CBD-rich chemotypes, often favoured for medicinal use.
CBC Synthase (CBCAS): This gene is less understood but contributes to the production of cannabichromene (CBC), a minor cannabinoid with potential therapeutic benefits.
Genetic markers for these synthase enzymes allow breeders to predict and select cannabinoid profiles during the early stages of plant development. This is particularly valuable for creating strains tailored for recreational, medicinal, or industrial purposes. More recent studies in 2022 showed us how much more we know after being allowed to study the plant. DNA studies have given light to disease prevention in the same way they have enhanced grower selection and breeding practices.
Selecting the Right Genetics for Your Grow
Choosing the right genetics involves more than picking a popular strain name. Growers must consider environmental constraints, cultivation goals, and personal preferences.
Desired Outcomes:
For recreational use, THC-dominant strains are popular. But let’s not exclude those who love the overall entourage effect etc. The market has shifted slightly and we are seeing the peak of THC-dominant strains in my opinion. Not only is it difficult to achieve this in breeding programs, but growers know that cannabis is more than just THC, and so the phase is thankfully over.
For medicinal purposes, CBD-rich strains are ideal. They still contain THC but the ratio normally is between 4:1 or 7:1 CBD to THC. Balanced strains with a 1:1 ratio of THC to CBD offer therapeutic benefits without overwhelming psychoactivity. These have also been sought after in the recreational market but due to overwhelming restrictions around cannabis in general it’s been a challenge to unlock full-spectrum CBD.
Resistance and Hardiness:
Growers in humid climates may prioritize strains resistant to mould, while those in arid regions focus on drought-tolerant genetics. Most cannabis breeders are international and in South Africa thankfully, we do have some awesome talent providing genetics that is resistant to Karoo heat and KZN moisture. We have the opportunity to produce such unique cannabis in our country because of our diverse climate. Given enough time, we will surely not have to use international genetics but have ours’ sought after.
The Role of Breeding and Stabilization
Breeding is the art and science of creating new cannabis strains with desirable traits. By selectively cross-pollinating plants, breeders aim to produce hybrids that combine the best characteristics of their parent strains. We have written about this before so please check out our Pollen chucking blog.
Creating Hybrids: Breeders combine sativa and indica traits to create hybrids that balance vigour, yield, and cannabinoid profiles. This practice has become so common that it is almost impossible to find pure sativa and pure indica on the market. Most strains are hybrids. I am not sure if this is a good thing or a bad thing. What I do know is that we still have ure sativa and indica strains and we should preserve them as well as breed more pure strains for the market.
Stabilizing Genetics: Through generations of selective breeding, traits such as height, flowering time, and cannabinoid content become consistent, resulting in a stable cultivar.
Recent advancements in genetic markers have revolutionized breeding. Using molecular tools, breeders can now predict a plant’s traits without waiting for it to mature, accelerating the development of superior strains.
Leveraging Genetics for Better Cultivation Outcomes
Consistency in Results: Stable genetics ensure uniform growth, cannabinoid levels, and terpene profiles, critical for commercial operations and medicinal users.
Improved Resilience: Strains bred for pest resistance and environmental tolerance reduce the need for chemical interventions, supporting sustainable cultivation.
Maximized Yields: By selecting genetics suited to your grow space, you can optimize plant size, flowering times, and bud density.
Future of Cannabis Genetics
Advancements in genetic sequencing and molecular markers are paving the way for precision cannabis cultivation. As research continues, growers will have access to strains engineered for specific effects, faster growth, and enhanced adaptability. These developments hold immense potential for both recreational and industrial cannabis, further blurring the lines between hemp and cannabis.
Cannabis cultivation begins with genetics. The DNA of a plant dictates its potential, shaping every aspect from growth patterns to cannabinoid content. By understanding and leveraging genetics, growers can align their practices with their goals, ensuring healthier plants, higher yields, and a more enjoyable cultivation experience.
Whether you’re a home grower or a commercial cultivator, investing in the right genetics isn’t just about choosing a strain—it’s about unlocking the full potential of cannabis as a plant and a partner in cultivation.
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