Genetic parameter estimation of growth traits in black carp (Mylopharyngodon piceus) by using a marker-based pedigree

Mylopharyngodon piceus is an important commercial freshwater aquaculture species in China, yet no improved variety has been successfully bred to date, resulting in an urgent demand for selective breeding. This study aimed to estimate genetic parameters of growth traits in M. piceus to provide a basis for formulating breeding strategies. An F₁ experimental population was established through artificial propagation using the Hanjiang population of M. piceus as broodstock. At 18 months of age, 566 offspring individuals were randomly sampled, and pedigree reconstruction was performed utilizing existing SSR parentage identification markers for this species. Combining the marker-based pedigree with phenotypic data of body length and body weight, genetic parameters were estimated using an animal model and the restricted maximum likelihood (REML) method. Among the 566 offspring, 551 were successfully assigned to 242 full-sib families, yielding an assignment success rate of 97.35%. The heritability estimates for body length and body weight were 0.48 and 0.43, respectively, both classified as high heritability. The phenotypic correlation coefficient between body length and body weight was 0.81, and the genetic correlation coefficient reached 0.92, indicating a high degree of correlation between these two growth traits. These results demonstrate that the available SSR markers can accurately determine parentage in M. piceus, and that 18-month-old M. piceus exhibit considerable selection potential for body weight and body length, thereby supporting future selective breeding programs for genetic improvement.