C. BARRING.

The presence of bands of black running at intervals across the otherwise white feather is a condition found in many types of poultry as well as various wild birds. It has become a fixed character in the Barred Plymouth Rock, which derived it in turn from the barred Dominique, whose barring was probably derived from the Cuckoo birds of England. Barring is also said to result from some crosses between white and black birds.

In my breedings barred birds have arisen several times:

(1) White Cochin × Tosa.—This case was referred to in my earlier report.[11] In the first generation of hybrids all males were barred. In the second hybrid generation I got 15 chicks that were white or nearly so, 25 with the Game color, and 16 barred. Remembering that only the males are barred and that the young heterozygous females are classed with Games, it appears that the barring is a heterozygous condition, occurring actually or potentially in about 50 per cent of the second hybrid generation and that, the whites and some of the Games are extracted types. This conclusion is confirmed by further breeding. In pen 663 I bred 2 extracted white hens of Cochin-Tosa origin to a white cock and got 12 chicks, of which all were white, except that 3 showed a trace of reddish color. From the extracted Games bred together I got 36 chicks, all Games. In the case of this cross, consequently, barring is clearly heterozygous and confined to the male sex.[12]

(2) White Leghorn Bantam × Dark Brahma.—This cross was referred to in my report of 1906. From the table given there it appears that I got 5 barred fowl in F1 out of a total of 51. In pen 701 I attempted to see if I could fix this barring. I used the best barred cock of the F2 generation and the best barred hens of F1 or F2. The result was as shown in table 66.

Table 66.—Distribution of color in F2 or F2 hybrids of the barred strain.
[Abbreviations: W.L. = White Leghorn; Dk.Br. = Dark Brahma.]

[A] Including 1 blue.[B] Including 2 blue.
Mother.Father.Offspring.
No.Gen.Races.Color.No.Gen.Races.Color.White.Black.Dark Brah.Barred.
721F1W.L. × Dk.Br.Dark barred.1898F2W.L. × Dk.Br.Barred....575
894F2Do.Well barred.1898F2Do.Do....93[A]10
965F2Do.Medium barred.1898F2Do.Do.21648
1335F2Do.Dark barred.1898F2Do.Do.11412
1772F2Do.Poorly barred.1898F2Do.Do....47[B]5
1915F2Do.Fairly barred.1898F2Do.Do....1045
2576F2Do.Do.1898F2Do.Do....9113
Totals (145)3673738
Percentages2.146.225.526.2

This result suggests the interpretation that one of the parents, probably the male, contains both heterozygous black and barring, while the other parent lacks the supermelanic coat and has homozygous barring. Then of the offspring half will be barred and half will be black and, consequently (since only the non-black show their barring), one-fourth will appear barred, one-fourth will appear of the Dark Brahma type, and half will be pure black or have the pattern obscured by the supermelanic coat.

(3) White Leghorn Bantam × Black Cochin.—In still another experiment (pen 511) I crossed a White Leghorn bantam and a Black Cochin as described in my report of 1906. Of 24 hybrids that developed, 10 were white or nearly so, 7 were black, and 7 were barred black and white. The White Leghorn was heterozygous in white (half of the offspring being not white) and heterozygous to barring. In pen 650 the barred birds were mated together with results as given in table 67.

On the assumption that the zygotic formula of both hens and cocks is BbN2Ww (compatible with a barred plumage) we get four-sixteenths of the offspring white, three-sixteenths mottled or barred and nine-sixteenths black or Game, thus approximating the observed result; i.e., 21, 16, 47 as compared with 23, 21, 40. The result supports the hypothesis of a barring factor, B.