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Basic knowledge of cannabis: genotype and phenotype

Basic knowledge of cannabis: genotype and phenotype

Many growers often misuse the words genotype and phenotype when talking about cannabis. Let’s remove all unnecessary confusion on this issue.


Genotype, environment, phenotype

Every living organism is the result of evolution, working on the same basic principle. The genotype, or genetic code, carries all the genetic information about growth, appearance and all the characteristics that can be observed later. It is crucial to understand that a genotype or genetic code is not something that is set in stone, but defines a certain range of possibilities. The environment in which an organism lives determines which bits of the genotype will be activated. The interaction between the genotype and the environment results in a phenotype, which is the physical expression of certain genes that have been triggered by the environment.

Common misconception

We have the idea that the environment is a determining factor influencing the genotype to express different phenotypes, but this does not answer the initial question of why each cannabis plant grown from seed seems to be slightly different, even when grown in a fixed environment (indoors).

How can a strain express different phenotypes if the environment does not change?

Well, it may be an inconvenient truth, but every single cannabis seed has its own unique genotype. Many growers assume that seeds from the same strain/strain of cannabis have identical genetic code and understandably expect homogeneous growth. Unfortunately, this is a common misconception. Many people use the term phenotype to describe the variation in plants that they get from the same strain/strain produced from seed. In fact, and what they don’t usually know, they talk about different genotypes. Phenotypic expression is not only determined by the environment, but logically also by the genotype itself.

When you buy seeds of a particular strain/strain, you will receive “family members” of that strain/strain that share a large percentage of their genetics with thousands of (inbred) siblings, but are not identical twins. The genotype is usually very close to identical, but there are still differences, comparable to twins if you like. This is the main reason why each cannabis plant grown from seed has minor differences in characteristics such as plant height, yield, taste, etc. – the genotype of the seeds is usually not the same.


Phenotype hunting!

Cannabis growers and breeders pay close attention to phenotype when deciding which strains to grow and cross. The practice of “phenotype hunting” allows a large amount of genetics to be quickly sifted through to identify traits that match their preferences and growing conditions.

The method involves sowing different strains/strains (or several seeds belonging to the same strain), breeding them, cloning them and searching for key traits.


Phenotype hunting allows you to test and try out a bunch of genetics at the same time. However, some growers choose to chase the phenotype by starting with seeds from the exact same parent plant. This process allows them to find the best phenotypes within a narrow range of variability in order to refine the best traits that a given strain/strain can offer.

Once the grower has found the desired phenotype of a particular strain/strain, he can retain these desirable traits by cloning the same individual over and over again. However, cannabis breeders can go one step further by breeding a phenotype of the same strain/strain and inseminating it by obtaining seed of that strain/strain and then crossing it with another strain that suits their needs. While adding more genetics back into the equation creates more variability, breeders can extract and stabilise the traits they like using techniques such as backcrossing.


Quick example: purple strains (strains)

Let’s look at an example related to cannabis to get a better idea. You buy seeds from a reputable breeder/seed bank and intend to grow a purple variety. Instead of growing all the plants in your indoor grow tent, you will decide to move half of the plants outdoors. Apart from the fact that no two plants seem to be the same as each other, you will notice that the plants in your outdoor garden are much richer in purple colours compared to those in your indoor growing tent. Although the genotype carries the information to produce the violet shades, it is the environment, and in this particular case the ambient temperatures, that allow two different physical expressions (phenotypes) from seemingly the same genetic code (genotype).

Which properties do Pheno Hunters want?

Some of the primary traits that phenotype hunters consider when sifting through genetics include:

  • Return to
  • Plant size
  • Peak size
  • Resin production
  • Cold/pest/stress/pathogen resistance
  • Colour
  • Taste and effect

We hope we have cleared up some of the confusion about a frequently asked question; genotype or phenotype.

In a future blog, we will write about the backcrossing method and cloning of undercrossers.