F1 (first cross)
This alpaca should be the offspring of a homozygous suri male over a huacaya female.
If a heterozygous suri is used, out of 4 offspring 3 will be suri in appearance and the other one will be born huacaya.
In addition, two out of every three suri produced will be like their parents, heterozygous, they will carry the huacaya gene which they will pass on to future generations. Only one in every four progeny produced from such a mating will be a homozygous suri which can be guaranteed to breed true suri type.

F2 (second cross) can still be called a F1
The result of mating a hetrozygous over a hetrozygous female.

BC1 (a first back cross)
The offspring of a homozygous suri male over a F1 female.

BC2 (a second back cross)
The offspring of a homozygous suri male over a BC1 female.

BC3 (a third back cross)
The offspring of a homozygous suri male over a BC2 female.

Suri
A full suri with no known huacaya within the last 3 generations.

Heterozygous Male
If a heterozygous male is used in a breeding program it is incorrect to describe the offspring as BC1, BC2 etc as the huacaya gene is being reintroduced not eliminated.

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