Abstract
This study was carried out in order to clarify whether a heterosis effect of locus, controlling the protein polymorphism of Japanese quail, is to be revealed by inbreeding or not. Test of single-gene heterosis in the inbred strain was examined on the acid phosphatase locus (Experiment I) and on the hemoglobin locus (Experiment II), independently. Brother-sister matings using the heterozygote of the acid phosphatase type or of the hemoglobin type were carried out to produce the inbred strains of Japanese quail. The authors ascertained the heterosis effect of each locus in each inbred generation by comparing the observed ratio with the expected one (1: 2: 1) from AB×AB martings. The results are summarized as follows. 1. Viabilities in the Experiment I and the Experiment II were ascertained to be about 80% in the initial generation (generation 0), decling with the advance of the inbreeding coefficient. The inbred strain in the Experiment I became extinct at the fourth generation. The strain in the Experiment II was maintained during the nine generations of inbreeding and it is now utilizing to produce the strain with more intensive inbreeding coefficient. 2. Progenies obtained from brother-sister mating using the heterozygote of the acid phosphatase type(AB×AB)were segregated into the phenotypes AA, AB and BB in the ratio of 1:2:1, in each generation, except the second generation. 3. Brother-sister mating using hetrozygote of the hemoglobin type, AB×AB, was carried throughout the 10 generations (0th-9th). The phenotypes of AA, AB and BB in each generation were segregated in the ratio of 1:2:1, approximately, although C-value (observed/expected number) of the BB phenotype was a little lower than those of the other phenotypes. 4. From the above results on segregation of phenotypes in both loci in each generation, it was recognized that the heterosis effect in these loci was not to be revealed by inbreeding.
