Understanding Cannabis Genetics: What Makes a Great Strain?
From landraces to modern hybrids — a plain-English guide to how cannabis genetics work and what to look for in a seed.
Landrace strains: where it all started
Landrace strains are the original, geographically isolated cannabis varieties that evolved over thousands of years in specific regions — Durban Poison from South Africa, Hindu Kush from Afghanistan, Thai from Southeast Asia. These strains are genetically stable and true-breeding, meaning seeds from a landrace will produce plants very similar to the parent. They're the building blocks of virtually every modern hybrid and are prized by breeders for their unique terpene profiles and resilience.
F1 hybrids
When two distinct, stable lines are crossed, the first generation offspring are called F1 hybrids. F1s often display 'hybrid vigour' (heterosis) — they tend to grow faster, yield more, and be more robust than either parent. However, F1 seeds are genetically diverse, meaning plants from the same pack can vary significantly in structure, aroma, and effect. This variation is actually desirable for phenotype hunters looking for exceptional individuals.
Backcrossing (Bx)
A backcross involves crossing an F1 hybrid back to one of its parent lines to reinforce specific traits. A Bx1 is the first backcross, Bx2 the second, and so on. Each backcross increases the genetic contribution of the parent line, stabilising the traits you want to preserve. You'll see this notation in our catalogue — Durban Poison Bx2, for example, has been backcrossed twice to the original Durban Poison, preserving its distinctive sativa character while improving stability.
Regular vs feminised vs autoflower
Regular seeds produce roughly 50% male and 50% female plants. They're preferred by breeders because males are needed for pollen. Feminised seeds are produced by stressing a female plant to produce pollen, then using that pollen to fertilise another female — the resulting seeds carry only female genetics. Autoflowering seeds contain genetics from Cannabis ruderalis, a subspecies that flowers based on age rather than light cycle. Autos are faster (seed to harvest in 70–90 days) and more compact, making them ideal for small spaces or outdoor grows with short summers.
What to look for in a seed
A healthy, viable seed is dark brown or grey with a hard shell and a waxy sheen. Tiger-stripe patterns are common and a good sign. Avoid pale, green, or white seeds — these are immature and unlikely to germinate well. Small cracks or damage to the shell can prevent germination. Seeds should feel firm when gently squeezed between thumb and forefinger — a seed that crushes easily is not viable. Store seeds in a cool, dark, dry place (ideally in an airtight container in the fridge) to preserve viability for years.
Phenotype hunting
Even within a single pack of seeds, individual plants (phenotypes) can vary in structure, aroma, potency, and yield. Phenotype hunting is the process of growing out multiple plants from the same cross and selecting the best individual for cloning or further breeding. It's time-consuming but essential for finding exceptional expressions. When we release a strain, we've already done extensive phenotype hunting — but growing out a pack yourself is the best way to find the pheno that suits your specific goals.