Comparative analysis of shell color variety and genetic structure among five high-quality freshwater pearl mussel populations.
Four Hyriopsis cumingii populations, a breeding population (BP), a cultured population (FP), two wild populations from Poyang Lake (PY) and Dongting Lake (DT), and an H. schlegelii population were collected (JX), and the first filial generations (F1) were bred synchronously. The shell nacre polymorphisms, population genetic diversity, and genetic structures of the F1 of each population were analyzed and compared using CIELAB colorimetric measurements and microsatellite markers. The color parameters of the shell nacre (L*, a*, dE*) in the BP were significantly different from those in the FP, PY, and JX populations (P < 0.05), whereas the shell nacre color did not differ significantly between the left and right sides of the shells within the same population (P > 0.05). The BP had relatively darker nacre at the posterior end of the shell, and the color parameters (L*, a*, b*, and dE*) differed significantly from those at the front end (P < 0.05). The five populations showed relatively high levels of genetic diversity (H = 0.733-0.829). The genetic distance between the H. cumingii populations and H. schlegelii was the greatest, whereas that within the H. cumingii populations and between the FP and the PY population was the smallest. All the individuals tested in this study were optimally grouped into four theoretical populations. In conclusion, the BP was significantly different from the base populations of PY and DT in terms of genetic background and phenotypic parameters of shell nacre color, with potential for further genetic improvement.