Swine enthusiasts- can someone explain what F-1, F-2, and F-3 mean?

Question

I know it has something to do with the percentage in crossbreeding. I think F-1 is half and half. Correct me if I'm wrong. Thanks for your time!

Answer 1

The F stands for "filial," which comes from the Latin for "son", and the number represents the generation.  F-1 is the "first filial generation," and refers to individuals produced from the breeding of unlike individuals; that could mean individuals who are known to be heterozygous for a given trait, or individuals of different breeds or types of swine.  F-2 is the "second filial generation," and refers to individuals who are the product of mating F-1 individuals.  Similarly, F-3 are the offspring of F-2 individuals.  This terminoogy is used throughout all of genetics and breeding, not just swine, and was first applied to the work of Gregor Mendel, the father of genetics.

Answer 2

I could explain this easier with a plant like corn, but it means the same for swine.  When  you mate two different types of swine, let's say the spotted Poland China x the dark red Duroc the resulting pigs will be the F1 generation.  The will be all alike 1/2 Poland China 1/2 Duroc.  This is usually called a hybrid cross.  If the F1 generation is allowed to inter-mate the pigs produced will be the F2 generation. This is a segregating generation. The pigs won't look alike.  You will have some pigs looking more like the Poland China breed and some looking more like the Duroc and everything in between.  If the F2 generation are allowed to inter-mate the resulting generation would be the F3 generation.  The F3 is another segregating generation, giving you more variety than the F2.  You would get a few pigs looking almost like the original parents and a wider variety in between.  Unless you are a breeder trying to develop a new breed of pig you would not let your animals go into the F2 and F3 generations.  If you are not raising purebred pigs, most farmers will cross breed and raise the F1 or hybrid pigs, which will perform better because of hybrid vigor.  These pigs will be sold for meat and not be used as breeding stock.  Each year a new generation of the F1 pigs will be produced.  I hope this didn't confuse you too much, I'm a corn breeder, but the principle is the same.

Answer 3

In genetics the F-1 is the first cross between two breeds or varieties resulting in a cross that is 50% of one breed and 50% of the second breed.  

The F-2 is The offspring of F- 1 individuals mated to similar F- 1 individuals.  This still results in an animal that is 50% of one breed and 50% of the second breed.  It also is used if the original 50-50 animal is bred to a third breed resulting in a 25% breed a, 25% breed b, and  50% breed c.

The F-3 is the offspring of two f-2 individuals and generally refers to the second generation of 50-50 individuals.  I beleive it is occasionally used to refer to crossing of 50-50 parentage animals from 4 different breeds.  

The terminology generally refers to all crossbreeding programs and is not restricted to swine or even animals since it can refer to crossbreeding of plants too.  Generally the crossbreds are more vigorous and productive than the parents which is referred to as hybred vigor.  This generally ends with the F-1 cross.  Furthur crossing as in the F-2 has more reversions to the types of the original breeds. I beleive the terminology can also be used in terms of strains within a breed of animals, but I am not sure that is accurate.