GENETICS OF THE BIRCHEN AND BLUE PLUMAGE PATTERNS IN LEONESA CHICKENS

Data are presented on the genetic basis for plumage color of the Birch en and Blue varieties of the Leonesa, a breed of Spanish chicken whose feathers are traditionally used by fishermen for the construction of artificial flies. Results of crosses between Birchen Leonesa males and Castellana (E/E Ml/Ml females suggested that the former carries the b irchen allele (E(R)) at the E locus. This allele is modified by the me lanotic gene (Ml), resulting in a self black plumage pattern. This fac t was further verified by the cross between Melanotic Prat (e(Wh)/e(Wh ) Co/Co Ml/Ml) males and Birchen Leonesa females. The degree of expres sion of E(R) is not modified by the columbian mutation (Co), although it is suggested that this gene produces nonblack lacing of the upper b reast feathers of some birchen birds. The data verify the existence of separate alleles for birchen (E(R)) and extended black (E) and clarif y the interaction between the birchen allele and the columbian restric tion and melanotic loci. Crosses between Blue Leonesa males and Brown (e(b)/e(b)) tester females showed that this variety was E(R)/E(R) and heterozygous for the blue (Bl) mutation. The absence of the melanotic gene in the Blue Leonesa resulted in light blue adult plumage and chic k down. It is suggested that the E and Ml loci are on different sides of the peacomb (P) gene because they segregate independently. Chick do wn data suggest that the birchen allele eumelanized the normally white ventral down of E chicks. The silver-faced black chick down of the si lver melanotic columbian phenotypes indicated that the e(Wh)/e(Wh) Ml/ Ml Co/Co genotype is a suitable background for color sexing involving the silver and gold alleles.