PRELIMINARY STUDY ON GYNOGENESIS OF SINIPERCA CHUATSI INDUCED BY HYDROSTATIC PRESSURE

Gynogenesis is an important way of parthenogenesis in fish. Compared with the selection breeding technology through the traditional sib inbreeding, because the genetic material of gynogenetic offspring is completely from the female parent, so it can be used as an effective means to quickly establish high homozygous strains, and has potential application value in fish chromosome operation, genetic improvement and sex control. Siniperca chuatsi is the main cultivated species of mandarin fish in China. In recent years, with the continuous improvement of cultivation yield, the germplasm resources related to growth and stress-resistance are degraded year by year, and the cultivation loss is serious. It is an effective way to establish pure lines through gynogenesis and apply them to the breeding of parthenogenetic lines and hybrid lines. This study first explored optimal inactivation time of the sperms of S. chuatsi and optimal fertilization times. It was found that the optimal inactivation time was 18min under the UV irradiation intensity. The most suitable fertilization time was 5 minutes before hydrostatic induction, and the optimal parameters for inducing gynogenesis of S. chuatsi were 2 minutes at 63 MPa. After HRM typing, the female rate of gynogenetic population was 100%. Based on the above parameters, the method put the culture dishes with sperms of S. chuatsi on the shaker and shake them slowly. The sperms in the culture dishes were irradiated by two 15 W ultraviolet lamps for 18min with the vertical distance of 17 cm between the culture dishes and the ultraviolet lamps. The inactivated sperms were fertilized with the female eggs for 5min, then treated with 63 MPa hydrostatic pressure for 2min, and finally hatched routinely with the hatching rate of 7.56% which was 3% higher than the existing method of cold shock induced gynogenesis of S. chuatsi. This study can be used for rapid population expansion of gynogenetic and all female lines of S. chuatsi, and for the creation of germplasm resources related to stress-resistance of S. chuatsi.