True F-crosses (Mendelian terminology)
T he genetic terminology of filial generations (F) has been a bit misused on the web concerning breeding-back, and I am guilty of it as well. While I used an “F” for any crossbred generation, no matter which genotypic combination, it should only be used when F1, F2, F3… individuals are mated to each other respectively if you want to use that terminology in a genetically correct sense. True F-cross products are interesting for breeding strategies because they are the most efficient way to fixate alleles in a more or less controlled way (while rampant cross combinations end up in genetic chaos) and to watch the Mendelian rules of inheritance (yes, most of the traits of a living organism are polygenetic, let us assume that for each of the single loci the Mendelian rules do apply). An F1 cross has one full set of chromosomes from one parental breed and one from the other. It has maximum heterozygosity that is possible between the two breeds, and is only homozygous for traits that are shar...