Age–age correlations and efficiency of early selection for growth traits and inner shell color parameters in a golden strain of Hyriopsis cumingii

Abstract

Hyriopsis cumingii is the most important freshwater mussel for pearl production in China, however, early selection for growth traits and inner shell color in this species is poorly characterized. To explore the optimal selection age, the growth traits (SW, SH, SL, and BW) and inner shell color parameters (L*, a*, b* and dE*) of 22 half-sib families were measured at the ages of 5, 12, and 17 months in a progeny test population established at the Weimin Aquaculture Company breeding base, Zhejiang Province, China. The phenotypic data for growth traits and inner shell color parameters were divided into breeding (50% growth traits × 50% shell color traits)and control groups and were analyzed. Age–age genetic and phenotypic correlations, and heritability were also examined. The results showed significant differences in growth traits between the two groups as age increased (P < 0.05). The b* values in the breeding group were considerably higher than those in the control group and the difference between the two groups was highly significant at all the tested ages (P < 0.01). The growth traits and inner shell color parameters had a moderate to high heritability (h2 ≥ 0.15) at all ages and b* values reached 0.44 at 5 months of age. The age–age genetic and phenotypic correlations of growth traits were always positive, ranging from 0.224 to 0.933 and 0.087 to 0.615, respectively. The age–age genetic and phenotypic correlations of the inner shell color parameters were also always positive, ranging from 0.224 to 0.954 and 0.097 to 0.816, respectively. The results of this study can be used to assist in the early selection practices for the selective breeding of H. cumingii's golden strain. For the early selection of growth traits and inner shell color, SH and b* are preferable, respectively, as target traits.