Response to four generations of selection for growth performance traits in mandarin fish (Siniperca chuatsi)

Selective breeding refers to the selection of individuals or populations with superior genetic traits from a population or family, for the purpose of directionally screening and enriching the dominant traits of the target species, to acquire breeds with directional dominant traits. The mandarin fish (Siniperca chuatsi) is an important high-quality freshwater fish widely cultured in China. The selective breeding of this species to obtain desirable growth performance traits has garnered considerable attention by researchers. We constructed a basic breeding population by selecting high growth as the target trait. Subsequently, we conducted family selection through four successive generations. We used the growth data (initial and harvest body weights) of the four generations of mandarin fish to estimate the realized heritability, selection response, and genetic gain, on the body weight of mandarin fish. We obtained the following values from generations F1-F4: realized heritability 0.17-0.47, selection response 0.40-1.12, and genetic gain 6.94-17.25%. The average genetic gain was 12.14%. Moreover, after four generations of breeding, the average growth rate of the selective breeding population had increased by 16.3% compared with that of the control group. This indicated that selective breeding had resulted in good genetic progress regarding the growth traits of mandarin fish and desirable selection effects. The coefficient of variation for the harvest body weight of generations F1-F4 decreased with increasing generation number (18.68-10.10%). This shows that the degree of variation in body weight among families decreased over generations, tending towards genetic stability after selective breeding. Our results provide a scientific basis and technical support for mandarin fish breeding and may serve as a reference for breeding other aquaculture species.