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Basic Breeding Terminology And Concepts

Basic Breeding Terminology And Concepts

By: Paul Josephs


Have you ever been shopping for a great strain and been perplexed by the terms and abbreviations? What does it mean when the breeder offers “An F2 Afghan Safari guaranteed to surprise you!” or says, “We’ve rejuvenated our IBL Gold Miner with this BX1 using our Columbian Gold mother.” It can be daunting to make sense of these seemingly cryptic descriptions, as if there is some secret breeder’s society you never were invited to join. Well, here is your personal invitation to the club.



A hybrid is the result of crossing two different varieties together. Take the hybrid Blue Cheese for example. This is a hybrid, or strain, created by crossing a Blueberry plant with a Big Buddha Cheese plant.


The F word

The F in F1, F2, F3, and so on is for Filial. This is an old word pertaining to son or daughter and in genetics refers to the offspring in terms of generations. An F1 generation is the First Filial Generation, the first generation of offspring from a hybrid cross. Using the Blue Cheese example, the first generation of seeds from the initial pairing of Blueberry with Big Buddha Cheese are F1 seeds. If the breeder takes two plants grown from these F1 seeds and crosses them, the resulting seeds and plants are F2 generation. An F3 generation is, well, I think you get the picture.



No it is not a new deli sandwich choice; IBL is short for Inbred Line. This is what you are getting with the F3 and beyond generations. IBLs should indicate that the strain or hybrid is becoming or is already stable for a number of traits. This stability is often referred to as true breeding, that you can expect certain traits to be consistently exhibited in the offspring.



Inbreeding can concentrate undesirable traits as well as desired ones,which is where a BX comes into play .BX is short for Back-Cross. A back-cross is taking an offspring plant and crossing it with one of the original parent plants. Say our F4 Blue Cheese is lacking some Blueberry traits. We can take an F4 plant and back-cross it with the original Blueberry mother plant if we have maintained a clone of the original Blueberry mother plant. This would create a BX1 generation. If this BX1 generation does not possess the traits we were looking for we can take a BX1 plant and back-cross it again to the Blueberry mother to once again reinforce the Blueberry traits. This is a BX2 generation. BX2 crossing is also referred to as squaring.


F1 and hybrid vigor

When a cross is first made and the parent strains are quite different – an extreme example would be a pure sativa crossed with a pure indica – the genes are going to be very mixed and different in the resulting F1 generation. In order to avoid launching into an in depth discussion involving more fancy terms, let’s just say that this F1 generation is going to produce fairly uniform offspring that tend to grow and yield vigorously. Hence the term hybrid vigor.


F2 and recombination

The mixed genes of the F1 generation will combine again to create a genetically diverse F2 generation. The general uniformity seen in the F1 generation goes out the window. In the example of the sativa crossed with the indica you can expect some resulting plants to look like a sativa, some to look like an indica and some to be intermediate. Thus the use of the word ‘surprise’ in the “An F2 Afghan Safari guaranteed to surprise you!” example given in the introduction.


Welcome to the club

Hopefully now you have a better understanding of the terms you often see in the search for great seeds to grow. Go impress your friends with your new vocabulary – “Yeah, bro, their IBL was getting tired out, so they juiced it up big time with that BX2 generation!” When they cannot understand what you mean, extend our personal invitation to join the breeders’ club.