It was once thought the perpetuation of the non-red betta was as simple as breeding a yellow to a yellow and standing back to enjoy the results. Indeed, some spawns of yellows do result in a high percentage (even 100%) of yellow fish, but the yellow phenotype has also been known to crop up in some unexpected places.
By all accounts, an extended red fish, having a dominant gene, should produce more reds and extended reds. However, in our experimentation with breeding extended red, we have had some spawns throw cambodian fish and yellow fish. Taking two of those yellow fish, we then did an F2 and got about 25% yellow. The remainder of the spawn was cambodian red. Using a different pair from the same F1 spawn (a red and a yellow) we got about 50% cambodian red, 40% red, and 10% yellow. Using two of the reds from that spawn, we got 100% cambodian red fish in the F3.
Yellow HM male (V. Parnell)
Now one of those fish was then taken and outcrossed to an extended red from another breeder's line. The extended red was a 6th generation red x red line fish; before that the breeder had crossed red onto black/orange to deepen the color. The result of this spawn was 40% cambodian red, 40% red, 10% extended red, and 10% yellow.
It was noted that the shade of cambodian on the cambodian red fish from these lines was more yellow than cream- or flesh-colored typical of traditional cambodians.
Yellow CT male (V. Parnell)
The yellows that came out as a result of the extended red crossings were less than the ideal shade of yellow. Some were very pale, others displayed the black-scale effect and didn't look 'clean'. These yellows are often called 'Pineapples', and are a result of a normally extended red fish showing the non-red phenotype. In an effort to eliminate the black scale from the pineapple betta, it has sometimes been crossed to red cambodian; these crosses, however, tend to produce a very washed-out, pale yellow. So it can be a challenging color to work, indeed!
According to Dr. Gene Lucas, yellow colored bettas do not result from the action of a single gene. There is no such thing as a yellow gene that produces a yellow phenotype in Bettas. Yellow Betta are phenotypes. The yellow color itself was designated as 'non-red' by Lucas. This 'non-red' recessive gene caused bettas to be yellow where they would normally be red. The reason why Dr. Gene Lucas did not call the gene yellow was:
1. The term non-red had been used previously to describe similar abnormalities in other organisms.
2. To avoid having people making the assumption that there was a single gene that would generate the yellow phenotype.
According to the IBC standards, yellow is categorized as a light-bodied, solid color type. To obtain a solid yellow, several changes must exist. The black and iridocyte colors must be minimized (eliminated if possible), the yellow must replace the red and the red/yellow must be extended to cover the entire fish. This requires four different alterations of three different pigment components. Two of these seem regulated by single locus recessive genes, the non-red already mentioned and the recessive cambodian gene which nearly eliminates dark pigment. The other two (the extension of red to cover the entire fish) and the reduction of iridocyte color to minimize green (or blue, if the green has been altered by still another gene) do not operate as though controlled by single genes.It is known that:
1. Yellow x Yellow may give Cambodian Red.
2. Cambodian Red x Cambodian Red may give Yellow too.
Intense yellow and pale yellow females (L. Xiong)
Cambodians and yellows are recessive but may carry each other's genotypes. Some claimed that Cambodians to yellows is a good cross to keep the yellow color as intense as possible. If you only spawn yellow to yellow it will eventually wash out and become a very pale, boring yellow.
Representative spawnings of yellow (NR), courtesy of Jim Sonnier:
- Victoria Parnell via Bettas4All. "Taking the Mystery out of Yellow" www.BettySplendens.com, . Accessed - December 23 2012 <http://www.bettas4all.nl/viewtopic.php?f=7&t=7754>