Principles of Genetics and Breeding

8.1.3.1 Irradiation of spermatozoa

Both gamma and uv radiation have been used frequently to inactivate sperm.

• Gamma radiation (often using a Co⁶⁰ source) has greater penetration and helpful in the treatment of large quantities of sperm at a time. However, residual chromosome fragments are frequently found in gynogenetic offspring after fertilization with gamma–irradiated sperm. Such fragments may reduce survival or cause abnormalities as reported by Purdom (1969).
• Therefore in the gynogenetic offspring, UV radiation is a preferred method for sperm chromosome inactivation and has been used successfully in a number of gynogenetic studies.
• The viability of radiation-induced diploid gynogenetic fish is seemed to be very low.
• Golovinskaia (1968) reported poor survival in carp, other cyprinids and loaches and similar problems were apparent in plaice, rainbow trout and in H. fossilis.
• On the other hand, high viability was reported by Stanley (1976) in grass carp.