Individual Hyriopsis cumingii were collected from Poyang Lake, Dongting Lake, and Taihu Lake, China, from which 17 paternal half-sib families, including 51 full-sib families, were produced using a nested design. After the cage culture of each family with ten replicates for 57 days, 30 individuals were randomly selected from each cage, totaling 15,300. Four growth traits were measured for genetic analysis in each mussel: shell length, shell height, shell thickness, and body weight. The heritability of each trait was 0.49 ± 0.37, 0.27 ± 0.29, 0.59 ± 0.39, and 0.47 ± 0.38, respectively. Phenotypic and genetic correlation between these four traits fell within the range of 0.89-0.95 and 0.97-1.00, respectively. Early growth traits of H. cumingii show sufficient genetic diversity for genetic improvement. Both phenotypic and genetic correlation between the four traits are high, and thus, the modification on one target trait may modify the remaining three traits accordingly. [ABSTRACT FROM AUTHOR]