Poly-hybrids derive from mixing completely different hybrids with each other. For example, Master Kush and Durban Poison produce offspring called F1(A); AK-47 and White Widow produce an offspring called F1(B). When F1(A) and F1(B) have a lovechild, it will be coined as a poly-hybrid.
Breeding cannabis is a complicated art that can be performed in plenty of ways. Here, we describe the common terms surrounding various cannabis genetics and how they came to be. We decided to keep it short and concise, as all the scientific minutiae can be very complex.
Backcrossing refers to taking a hybrid strain and breeding it back with the original parent. For example, a male Chocolope and a female Jack Herer develop an F1 hybrid. When this F1 hybrid is hybridised with the original female Jack Herer, the resulting strain will be coined as BX1. When this BX1 gets backcrossed again with the original female Jack Herer, it will be coined as BX2, and so on. The genetics of the original female strain can be retained by keeping the plant in the vegetative stage as a mother, keeping the cuttings as clones or using tissue culture propagation.
Landrace varieties originate from regions where cannabis plants have been growing for a very long time in the wild—centuries, or even millennia. This naturally creates stable, robust genetics that produce a homogeneous offspring. This means that the landrace strains from a particular area will develop very similar growth patterns, appearance, and chemical composition. Hindu Kush or China Yunnan are examples of pure landrace strains.
F1 stands for a “first generation hybrid”. When two strains with completely different genotypes breed, for example, a Master Kush with Durban Poison, their offspring will be an F1 hybrid. When this hybrid is bred together with another F1 hybrid from the same batch (a sister or a brother), it creates an F2 hybrid. When this process is repeated, it creates an F3, then F4, and so on. After F5, the plants can be considered as IBL.
IBL stands for “inbred line”, meaning that after several generations of hybridising a specific lineage, the strains become almost like a different family of strains. Skunks were hybridised and selected for their very pungent and potent nature, and after many generations, they developed into the Cheese family, which can be called an IBL.
With each successive selection, the grower selectively takes the plants that are the best representation of the properties he desires and uses them for crossings.
Pure-breeds are unadulterated traditional landraces that have only interbred with similar strains and so have almost identical genes.
So the main difference between F1, F2, and F3, etc. is simply the generation and level of stability that comes with them.
Let’s take a large plant (represented by two dominant genes, AA)
and cross it with a small but bushy plant (represented by the two
small recessive genes, aa). Since the resulting plants each receive
one gene from each parent, this will result in offspring with the following genetic makeup: Aa. All four offspring have the same makeup and will each be tall bushy plants.
To make a well-informed decision when deciding on what the ideal seeds for you, it is helpful to understand the differences between these different generations.
You create an F1 strain by crossing two pure strains with completely different phenotypes. To achieve this, the grower will, for example, take 100 of their best plants and select only the very best mother plants based on a specific trait from one strain.
Once you’ve achieved a level of stability in your F3 variety, it is time to take your game to the next level. By continuing the selection process and using only the most stable plants from the previous generation, we’ve now reached the F4 variety.