What Is the Difference Between Genotype and Phenotype?

What Is the Difference Between Genotype and Phenotype
May 15, 2020

Genotype versus phenotype.

A cannabis plant’s genotype refers to the specific genes it carries. A plant’s phenotype refers to the observable traits and characteristics, affected both by genotype and environment. Differences in a cannabis plant’s genotype can result in different phenotypes.

What do these differences mean to cannabis growers, especially those growing at home? What do homegrowers need to know about phenotypes and genotypes?

When growing cannabis, it’s probably reasonable to expect the seeds you buy will produce a crop of identical plants. As we shall explain, there are sound, scientific reasons why this isn’t always the case.

It’s not a wholly accurate comparison (being as humans have a far more complex genome than cannabis seeds) but you can think of a seed as a human child. The child, like its parents, should have the same general traits: two arms, two legs, mouth, nose, ears, hair etc… but they won’t look exactly the same.

The differences between children and their parents can seem HUGE. But, to an alien, they would seem as subtle and insignificant as the slight differences you might see within your crop. The plants grown from your eight White Widow seeds will look largely the same, but it’s important to understand that variation is possible, and natural. It is easy to assume there might have been a mix-up with the seeds, but it’s far more likely you’re witnessing the natural, genetic diversity of unique genotypes.


Autoflower Marijuana Plant

In summary…

Genotype can be thought of as the blueprint of the plants, the genetic makeup that determines traits and characteristics. Each seed will carry it’s own, unique genotype containing subtle variations of the specific cultivar genome. Genotype can only be determined by biological tests, not observations. The genotype is genetic information, not genetic expression.

A phenotype is what occurs when a genotype interacts with the environment, distinguishable by things like physical appearance and terpene/cannabinoid levels. A plant’s genetic information is encoded within the genotype. It’s interaction with the environment produces the phenotype. As all growers are aware: light, water, nutrients, temperature, humidity and so many other factors ALL contribute to the resultant phenotype.

Phenotype and Genotype FAQs

What is phenotype variation?

As we discussed, the cannabis phenotype is the genetic expression of a genotype within an environment. A good example of phenotypic variation is the flamingo. These are naturally white birds that turn pink because of the canthaxanthin (a pink dye) found in their food. If two identical twin flamingos were brought up with a different diet, one would grow pink while the other stayed white.

They would still be identical twins, but the diet-based phenotypic variation will make them look dramatically un-identical!

Do all cloned plants have the same genetic makeup?

There is one way to produce an identical cannabis plant from its ‘parent’ and that is cloning. To create clones, growers take clippings from a carefully selected cannabis plant before transplanting and growing it out. If grown in the exact same conditions as the parent you will have yourself the exact same plant. The genotype will be identical therefore all the traits will be identical.

Grow this clone in a different environment, however, and you will probably see some phenotypic variation. Just like the flamingos, the identical genotype will find different expressions.

How do cannabis strains express different phenotypes within a fixed environment?

As we touched upon earlier, every cannabis seed contains a unique genotype. And this is where it gets a little hazy for many growers. While it’s true that every living plant is a phenotype, the variations within a controlled grow are far more likely down to the special genotype of each plant. Genetic diversity is normal and natural. It’s at the very heart of evolution. Without it there would be no cannabis plants and certainly no humans around to cultivate and cure this wondrous herb.

Cannabis Cultivation