Abstract
The authors has been succeeded to induce the translocation of yellow blood (Y) gene on the 2 nd chromosome to the W-chromosome in the silkworm, by the irradiation of pupae with γ-rays at 6000 R for 20 min. This strain shows sex-limited inheritance on the blood color, namely the color is white in the male and yellow in the female. By the coexistence of cocoon color gene C, the cocoon color also shows sex-limited inheritance ; white in the male and yellowin the female. Therefore, the sexes can be easily discriminated by cocoon color and this translocation is very usefull for the crossing to produce F1-or poly-hybrids in commercial silkworm breeds.
