Associated effects of the roux plumage color mutation on growth, carcass traits, egg production, and reproduction of Japanese quail

After two generations of introgression of the sex-linked recessive roux col or mutation into a commercial broiler Japanese quail line with wild-type pl umage, growth, carcass, egg laying, and reproduction of birds were evaluate d and compared for all types of birds produced (considering sex, line, and plumage). Usual sex differences were obtained for BW, with larger values in females and 5% sexual dimorphism. Weights were larger also in the pure com mercial line, which had a higher hatching rate (HR) than the introgressed b irds at 17 to 19 wk of age. Rowe plumage was significantly associated with 3% lower BW and 30% less abdominal fat (AF) pad. Egg production was not inf luenced by the roux mutation, but egg weight (EW) was 2% lower. Characteris tics associated with the roux gene are similar to those reported for the al bino mutation, except for AF, which was not tested in albino quail. The sim ilarity of the pleiotropic effects might result from some modification that the two mutations induce in an early step of a metabolic pathway involved both in coloration and in growth. From a practical breeding standpoint, the roux gene appears to be a interesting candidate gene for auto-sexing in qu ail production.