The Kooky Kiwi
Crowing
According to my readings there should be several "theoretical" ways to go about it. In very simple terms a Citrone (or similarly coloured bird) is effectively a dilution of the gold/red base. I've considered that any of the following genes could be used to achieve a dilution effect and from there it's just a matter of preference based on how much dilution and the "tone" of the dilution that you require. You could have three birds, each diluted by a different gene method, and they would plausibly have subtle differences in colour. Lemon vs Buff vs Cream vs Citrone? And then of course it's whether or not any of these genes are present in your project population to work with!
Di - Dilute (Dominant - Dilutes Red & Gold)
Cb Champagne Blond (Dominant - Dilutes Gold)
Ig - Inhibiter of Gold (Recessive - Dilutes Gold to Lemon)
I also have another theory, which I have contemplated with reference to my previous experience breeding mutation cockatiels. In cockatiels you have sex linked colours, for example Lutino and Cinnamon. With careful breeding and patience (lots of patience) you do sometimes achieve a "crossover" and combination of those sex linked genes. A common practice is to start one parent of each to get a male who is "split" to the desired colours - I.e Lut / Cin. For the most part his hen babies will be either Lutino or Cinnamon (following sex linked rules) but there are also occasions where the colours cross over and you get a combination hen - Lutino & Cinnamon in one bird.
Following this logic - is it then possible for a crossover of this type to occur in a sebright? If you start with the rooster who is split silver/gold (S+ / S-) - could you get a crossover and achieve a hen that is S+/S-? We already see the colour effect of this combination in roosters (the lemony hackles) so if it were possible to combine the S+ and S- in a hen you would plausibly expect to see a similar colour effect - ergo Citrone?
If such a crossover were achievable - this would account for the rarity of the colour here in NZ because the chances of such a crossover could indeed be very small to achieve. It could also explain how it was possible to achieve a Citrone bird in the manner described by the breeder who produced my original citrone.
I just have a nagging thought in my head, that if Citrone was achieved by way of one of the dilution genes discussed above, then we should be seeing more diluted birds in our population here.
