A consecutive self-proliferate silver carp (Hypophthalmichthys molitrix) variety created through artificial meiotic gynogenesis

In this research, meiotic gynogenesis (meio-gynogenesis) was used in our silver carp (Hypophthalmichthys molitrix) breeding program. Three natural sex-reversed male individuals were found in a second generation meio-gynogenetic strain, and these were used to construct self-proliferate strain. Through morphological trait selection and growth rate comparison, an excellent variety was established, which was named the “Changfeng silver carp” (CF variety). In this study, we compare the genetic, morphological traits and growth rate between the CF variety and the common silver carp species. The average genetic identity of the CF variety is 0.98, and the ratios of full length/body height and body length/body height are 5.87% and 7.21%, respectively, which are significantly higher than those of the common silver carp. These data indicate that the caudal fin of the CF variety is shorter than that of the common silver carp. Principal component analysis (PCA) showed that the morphology between CF variety and the common species is diverged at principal component 1 (PC1), and stepwise discriminate analysis showed that the CF variety and common species can be discriminated by the combined usage of full length, body height and head length, the respective total discrimination accuracies of which are 90.9% (original) and 90.7% (cross-validation). Growth rate comparison tests in two consecutive years proved that there is no significant difference (P > 0.05) at age of one year, while the growth rate of the CF variety is 12.27-17.88% faster than that of the common species at the age of two years. These results demonstrate that the combined usage of meio-gynogenesis and morphological traits selection is a feasible and effective method to create an excellent and creditable variety, especially for fish with a relatively long sexual maturity cycle.