Diploid gynogenesis induced by hydrostatic pressure in loach, Misgurnus anguillicaudatus

Abstract

Diploid gynogenesis in loach was induced by hydrostatic pressure ranging from 500 psi to 12,000 psi generated by a French Pressure Cell. Loach eggs fertilized by UV-irradiated sperm and exposed to hydrostatic pressure of 4,000 psi for 5 min resulted in the highest hatching rates and percentages of diploid gynogenetic fry. All haploid fry were deformed and died within four days of hatching. The morphologically normal fry were confirmed to be diploid. In the study on the effect of exposure of duration 1-9 min, results indicated that 2-5 min contributed to the comparatively good combination of high hatching rate and high percentage of diploid gynogenetic fry. Attempts to compare the use of hydrostatic pressure and the application of cold shock, which was reported to be reliable for the induction of diploid gynogenesis in loach, were made. The hatching rates and percentages of normal diploid gynogenetic fry were found to be inferior in the hydrostatic pressure method.