New Grower? Here’s What You Need To Know About F1, F2 & IBL

Need to brush up on some cannabis breeding vocab? Here’s all you need to know about first generation (F1), second generation (F2), and inbred lines (IBL).

Jan 2, 2017

Anyone searching for seeds may have noticed a few phrases listed next to the genetic information. F1, F2, and IBL are three initialisms that explain quite a lot about the background of the plant. To help improve your cannabis breeding vocabulary, here’s the scoop on first generation (F1), second generation (F2), and inbred line (IBL) crosses.

How are new strains created?

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As many cannabis fans have probably noticed, there are a lot of different strains out there. The vast majority are hybrids. Hybrids are strains created through the selective breeding process.

New strains are created by breeding two parent strains together over many different generations. Strains that have adapted to their native environment over time through natural selection are called landrace strains.

This hybridization process was first introduced in the late 1850s by a monk, Gregor Mendel. His first experiments were among pea plants. He bred two different varieties of peas together and continued to breed their offspring. He followed the offspring for two generations and recorded their traits.

Mendel discovered that the majority of plants will produce one common trait, such as a darker color. A minority of offspring will produce other traits, such as a lighter color. This simple observation is instrumental to modern genetics. Mendel had discovered that some physical traits are dominant and some are recessive.

A dominant trait is a trait that is most likely to express. A recessive trait is one that is usually hidden in the first generation (F1) of hybridization yet will show up in further crosses.

What are inbred lines (IBL)?

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Inbred lines are essential for coaxing out recessive traits and creating a homogeneous strain. Strains are bred together repeatedly through multiple generations, selecting for certain traits each time.

Continuously breeding these strains together creates offspring that are nearly identical. Seeds should produce plants that are all strikingly similar.

For example, popular myth has it that the indica strain G-13 was bred over 13 generations before being unexpectedly released to the public. Some breeders take years to develop the perfect strain, as was the case for Charlotte’s Web, the world’s most famous high-CBD cannabis strain.

The initialism “IBL” next to a strain name indicates that the strain has been bred with itself for two or more generations. Other common initialisms include “F1” and “F2”, which signify the generation.

First Generation (F1)

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A cross between two parent strains produces an F1 offspring. F1 stands for first filial generation. Filial is derived from the latin word for “son”. Dominant traits are typically more predominant in the F1 generation. To coax out recessive traits and “stabilize” a strain, these F1 generations need to be crossed with each other.

Second Generation (F2)

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When F1 hybrids self-pollinate, it creates an F2 hybrid. Recessive traits will be more apparent in the second generation. F2 hybrids have been born from plants that carry both dominant and recessive traits. The F1 generation inherited both of dominant and recessive characteristics from the original parents.

These inherited characteristics are also called phenotypes. Because each offspring can inherit dominant and recessive traits,  a single strain can produce various phenotypes.

The popular strain Blue Dream, for example, produces both indica-dominant and sativa-dominant phenotypes.

Generations and phenotypes are also the reason why there are so many popular varieties of OG Kush strains, including San Fernando Valley OG, Larry OG, and Bubba Kush.

Phenotypes from OG Kush were selected by various breeders over time, then consistently bred to create a homogeneous strain.

Jan 2, 2017