All you need to know about cannabis phenotypes and genotypes

All you need to know about cannabis phenotypes and genotypes
Miguel Antonio Ordoñez

Cannabis genotypes and phenotypes, two buzz words used often by breeders, growers and smokers. Find out what they mean at CannaConnection!

Have you ever wondered what gives your favorite cannabis strain its unique characteristics, such as its complex aromas and flavors, or the unique high it produces? Or, have you ever found two seedlings from the same batch of seeds develop into two completely different plants once they’re matured?

It all comes down to genetics. In this article, we take a look at cannabis genotypes and phenotypes, two buzz words that regularly make it into articles on grow tips but are hardly ever explained in details. Especially 'phenotype' is an word used often, while a lot of people do not exactly know what it stands for.


All organisms have phenotypes and genotypes.

Phenotypes can best be described as the observable traits of an organism. A genotype, on the other hand, is the genetic makeup responsible for creating those traits in the organism.

In humans, some obvious phenotypes include the colour of our hair, eyes, or skin. Our genotype, however, is the set of genes in our DNA that make us display those specific traits.

Plant phenotypes/genotypes work exactly the same way.

The phenotypes of a cannabis plant, for example, can include the plant’s structure and appearance and smell, while the genotype refers to the genes in that plant’s specific DNA that make it have those traits.

Gregor Johann Mendel is often considered the founder of the modern study of genetics, and is often referenced when discussing the difference between phenotypes and genotypes.[1]

Mendel worked with 7 characteristics of pea plants: plant height, pod shape and color, seed shape and color, and flower position and color.

When he crossbred his plants, Mendel found that first generation crosses between green and yellow pea plants were always yellow, while the second generation of plants sprouted green at a ratio of 1:3.

To explain this phenomenon, Mendel coined the terms “recessive” and “dominant” in to refer to certain traits (such as the green/yellows traits of the peas). He published the results of his studies in 1866, stating that invisible “factors” (now referred to as genes) were responsible for creating these traits.

Mendel's work, unfortunately, didn’t receive recognition until the 20th century, when Erich von Tschermak, Hugo de Vries, Carl Correns, and William Jasper Spillman first verified his findings.[2]

Cannabis plants take on the traits from their mothers and fathers, much like humans do. And, just like two humans can have twins that are completely different (both physically and emotionally), so can cannabis plants.


Here’s an example of genotypes and phenotypes at play in cannabis plants.

In a letter to High Times’, a reader named Mayhem explains the following scenario.

“[My plants] are all second generation from a plant I grew last year which produced about 50 seeds total. Of the 50 seeds I planted 25, and now I have 15 mature plants, 10 of which are indica-looking and 5 more like sativas,” writes Mayhem.[3]

“One plant produced all the seeds I have growing at this point but I most definitely have two entirely different plants in size, smell, and growth rate. The size difference is also questionable as my indica-looking strains are all about 5-6 feet tall and bushy and all the sativa-looking plants are over 8-10 feet tall. Main question is how did I get two entirely looking, smelling and growing plants from seeds I have grown myself.”

What Mayhem is experiencing is genetic diversity at it’s best. He used seeds from one batch and ended up growing 2 different phenotypes (in short: pheno's)


Expert breeders manipulate the genotypes/phenotypes of a variety of plants in order to create unique strains with beneficial traits.

For example, growers often cross indicas and sativas to create strains that create large, fat buds in relatively short grow times (typical of indica varieties) and produce strong, uplifting, and creative cerebral highs (typical of sativa strains).

Alternatively, breeders might be looking to take advantage of the structure/physical build of a specific strain to create a variety that’s suited to specific a specific grow environment. For example, many seed banks offer strains which produce distinct sativa highs yet grow like an indica (relatively short yet bulky) to accommodate for indoor growers.

Finally, breeders also look to crossbreed strains for their chemical make up. For example, medical seed banks will usually cross high CBD strains with THC-rich strains to create varieties with more powerful medicinal properties.

By understanding the traits of your plants and, more importantly, that genes that give your plants their distinct characteristics, you’re able to experiment with the genetics of your different plants and crossbreed them to create new, varieties with unique characteristics.


  1. ^ Wikipedia, Gregor Mendel, retrieved October-31-2018
  2. ^ Cropwatch, Gregor Mendel and His Peas the Origin of Modern Genetics, retrieved October-31-2018
  3. ^ High Times, Grow Q and A What Are Phenotypes, retrieved October-31-2018

Miguel Antonio Ordoñez
Miguel Antonio Ordoñez

Miguel Ordoñez is a long-time writer by trade. Utilizing his AB Mass Media and Communications degree, he has 13 years of experience and counting. He’s covered a wide array of topics, with passion lying in combat sports, mental health, and of course, cannabis.