Inheritance of Temperature-sensitivity Characteristic of Silkworm (Bombyx mori) Embryo and its Application in Sex Control

摘要

Silkworm eggs of some races, such as the sex-limited race of the body color of newly- hatched larva, 965 Limit, and the sex-linked chocolate races, Banl and K05, showed the temperature-sensitivity under high temperature and low humidity incubating condition. It was demonstrated that the temperature-sensitivity was controlled by a major gene on Z sex chromosome and showed recessive sex-linked inheritance. The gene was activated when eggs were incubated under high temperature and low humidity, and its expression is at the later stage of the embryonic development. It shows a practical method of commercial rearing of only male or female silkworm by artificially controlling the incubating temperature and humidity due to the difference of temperature-sensitivity between the male and the female. The hatching ratio of female to male was 94.60:5.40 for 965 Limit under high temperature and low humidity. When F_1 eggs of normal silkworm varieties (♀) crossing to temperature-sensitive varieties (♂), incubated under high temperature and low humidity, the average hatching ratio of female to male was 4.42:95.58. It basically can be put into effect for single-male or single-female rearing.