Genetic effects and genotype × environment interactions for growth-related traits in common carp, Cyprinus carpio L.

A diallel cross was conducted with three variants of red common carp, Cyprinus carpio var. singuonensis, C. carpio var. wuyuanensis and C. carpio var. color, raised in two separate experimental stations. Additive effects, dominance effects, additive × environment (A × E) and dominance × environment (D × E) interactions of growth-related traits of 8-month-old fish were estimated by using a mixed genetic model. It was found that the traits of body weight (BW), standard length (SL) and pre-dorsal height (PDH) were mainly controlled by dominance effects, whereas they were very weakly controlled by the additive, genotype × environment (A × E and D × E) interaction effects. For the trait of pre-dorsal width (PDW), additive effects were the predominant effects, while dominance and genotype × environment interaction effects were less important. Also, significant D × E interaction effects in BW, and significant A × E interaction effects in PDH and PDW were detected. In all the studied traits, the prediction of genetic merit (breeding values) for the three variants indicated that C. carpio var. color was the best one for genetic improvement through direct selection in different environmental conditions, and the cross combination of C. carpio var. color and C. carpio var. singuonensis was the best for heterosis utilization by hybridization, while C. carpio var. wuyuanensis was the best for improving the body height in red common carp.