Weed From Seed: Understanding F1 Hybrids

Breeding is a fascinating subject to examine as it is the backbone of commercial agriculture and is crucial to the success of the farmers’ crops. Without stable and vigorous genetics, a farmer could have massive issues with their crop, leading to a huge loss of revenue. Due to the cannabis industry living in the shadows for so long, breeding was largely relegated to closets and amateur “pollen chuckers,” people crossing random plants in the hope of getting something new and desirable. This is where the term phenohunting comes from. By crossing heterozygous parent stock, the genetics of the progeny, or phenotypes, would be filled with variance. As a result, the progeny would have variants that expressed recessive genes, as well as plants with genetic mutations. This might be desirable when looking for something unique or new, however, these plants could also inherit undesirable traits like hermaphroditism or become more susceptible to illness or pathogens.

With cannabis breeding and cultivation being illegal for so long, the other issue that breeders ran into was the threat of having their plants or seeds seized in a raid. Many breeders in Amsterdam and other places around the world have faced this problem, which has led to cases of lost rare genetics. The threat of having your grow discovered also meant it was challenging to run an extended breeding program because you never knew how long you had in one spot. 

This is one reason why a true F1 hybrid remains a rarity amongst seed companies. It was always possible to find some strains that were naturally homozygous (possessing two identical forms of a particular gene, one inherited from each parent), and when grown out from seed, the population would have some degree of uniformity. Still, it was rare to find uniformity above 92%.

These days, the term F1 hybrid has become a new marketing catchphrase for cannabis seed companies. Often, seed companies advertise that they now have genuine F1s—and some of them might have actually taken the time to accomplish that—but the process of stabilizing parents to the point of true breeding stock can take years. It also helps to have a lab that can run portions of the plant’s genetics through a DNA sequencing system, as that’s really the only way to know the amount of homozygosity in your plants with certainty.

The very first recorded example of an F1 hybrid was observed by an Augustinian monk named Gregor Mendel in the 19th century. The “F” stands for filial, which means “first child,” and in this earliest example of selective breeding, Mendel used two different strains of green pea plants and cross pollinated them to create a new F1 hybrid pea strain. The new strain he created was heterozygous and, therefore, expressed different genes from its parents. This occurred because the parent seeds were pure (“inbred”) breeding stock or homozygous, meaning they had a set of genetically uniform traits that would be passed to the child cross.

In the case of cannabis, this could be one parent with a dominant gassy terpene profile and another with a dominant purple color. By knowing which traits in the parents were dominant, a breeder could predict what the offspring cross would look like and breed with purpose. In the example above, the new cross would take the dominant parts of the parent and would produce an offspring that was gassy and purple. This combination of genes would make the new cross heterozygous, giving it heterosis or hybrid vigor. Moreover, by starting with stable inbred parent stock (strains crossed back to themselves otherwise known as inbred, backcrossed or selfed), the new cross would have a high degree of uniformity. Even though the new cross would be the genetic combination of the parents, the population would have inherited the same traits across the whole generation.

The key to growing from seed is having a uniform, stable, and vigorous plant. This is why a true F1 hybrid seed would be a game changer for cannabis growers, allowing them to start from a seed, which results in a better yield and a stronger plant than their normal clone starts. Cannabis is one of the few industries that exclusively use clones in commercial cultivation. Almost every other agriculture sector uses seeds as their starting source because of the vigor and strength of an F1 hybrid.

Humboldt Seed Company is one of the few companies that has been working on F1 hybrids in conjunction with a lab that offers them the ability to run their plants through a gene sequencer. This shows them the degree of zygosity their parent plants have, allowing them to accurately predict the outcome of their selective crosses. The key to their breeding program is working with stable inbred parent stock. This means they might self the parent plants to a sixth or seventh generation, ensuring that the parents are as homozygous as possible. This way, you have a predictable parent and can create predictable offspring that show a combination of the parent’s most dominant traits. For example, when you buy a pack of Humboldt Seed Company’s OG seeds, you will get a uniform set of plants that all smell gassy and have a similar growth structure—the same with their Blueberry Muffin strain, which always produces plants that smell like blueberries.

As the industry matures, more seed companies will likely look to stabilize their inventory of mother and father plants to produce more F1s. This will also come as a major benefit to cultivators as they will finally be able to join their agricultural colleagues by using seeds to start their crops. This will see more robust plants and greater yields for the gardeners, giving them the chance to also lower their costs as the same square footage of their grows will now potentially produce 20-30% more flower. Ideally, the cost savings would be passed down to the consumer, giving them a higher-quality flower with a slightly lower price. The emergence of true F1 hybrids in cannabis is a positive new step for an industry held back by years of existing in the shadows of illegality.

This article was originally published in the February 2024 issue of High Times Magazine.