| Filial
generations and back crosses in the domestic pigeon
It is a waste of time and
effort if the reader can only guess from reports on experimental
breeding what has been going on. A reason often is a very
individual, not to say wrong use of terms by the authors. The first
cross breed is called F1 (1st filial generation). The
subsequent generation F2 arises from the individuals of
the F1. In many reports about a “F2”, a F2
was not generated at all. Instead, a first back cross was made to
the original breed. Anyone who has taken the advice literally will
be disappointed with the breeding-receipt in the own loft.
An example to demonstrate
the difference: A blue racing homer cock with a platinum-colored
Pomeranian Eye-Crested hen with eye crests (eye brows) raised only
black, plain-headed youngsters without eye crests (the F1).
Fig. 1: Mating of blue bar
Racing Homer cock and a platinum Pomeranian Eye Crested Highflyer
hen with two young of the first filial generation F1. Soruce:
Sell, Taubenzucht, Achim 2019
The F2, the young
from the pairing of the F1 with each other, was plain
headed, lacking also eye crests. According to Mendel, some
individuals with small crests (from the hen’s side) could have been
there. With the relatively small number raised, however, they were
not.
 
Fig. 2: Selected young from
the F1 (at the left) and a young cock of the F2
(at the right)
It is quite different with
the first back cross on Pomeranian Eye Crested Highfliers. Around
half of the young had a crest, although not particularly pronounced.
In average, however, better than the few you would have obtained in
a F2-generation as is known from former crosses. In
addition, some with small eye crests and some youngsters even in the
platinum cock color. In further backcrosses, the structure of the
feather structure will quickly increase with proper selection of the
best young for further breeding.
  
Fig. 3: Backcross of a F1
hen upon a platinum Pomeranian Eye Crested cock (photo at the left)
and in the middle and at the right a black and a platinum young cock
of the first backcross.
The principle of
back-crossing is well documented for the introduction of dominant
color traits such as indigo, but is also useful in other cases.
Shown is that with many examples in the relevant literature.
Fig. 4: Examples of the
transfer of indigo to other breeds. Sourcee: Sell, Pigeon Genetics,
Achim 2012
Crossings with other breeds
are often done to transfer characteristics such as color and feather
structures from one breed to another. But very often also about the
viability of your own race. Many rare breeds would have suffered
from inbreeding depression and would still have got extinct without
the occasional crossbreeding with other breeds!
 
Fig. 5: Source books –
www.taubensell.de
Literature:
Sell, Axel, Pigeon Genetics.
Applied Genetics in the Domestic Pigeon, Achim 2012.
Sell, Axel, Taubenzucht. Möglichkeiten und
Grenzen züchterischer Gestaltung, Achim 2019.
|
