Genetic parameter estimation of nine quantitative traits by a marker‐based method in Large Yellow Croaker,Larimichthys crocea (Richardson)

Large yellow croaker accounts for the largest biomass production of any maricultured fish in China. However, very little is known about the genetic parameters of its commercially important traits. As an initial step towards developing a selective breeding programme, genetic parameters of nine quantitative traits were estimated using a marker‐based method. Dorsal fin samples were collected to extract genomic DNA, and GBS method was employed to construct the libraries for sequencing. Genetic parameters were estimated by REML method through a genomic relationship matrix (G matrix) constructed by abundant genomewide SNPs. The nine traits were body weight (BWT), body length (BL), body height (BH), length/height ratio (LTH), body width (BWH), eviscerated weight (EW), gonad weight (GW), eviscerated weight/body weight ratio (REB) and swim bladder index (SBI). Estimates of heritability were 0.63 ± 0.11, 0.60 ± 0.11, 0.53 ± 0.11, 0.34 ± 0.11, 0.55 ± 0.11, 0.66 ± 0.11, 0.37 ± 0.10, 0.25 ± 0.08 and 0.71 ± 0.10 for the nine traits respectively. The relatively high heritability values may be derived from calculating the genetic relationship by high‐density SNPs. To illustrate that, we had studied on the variation of the heritability estimates with different number of SNPs evenly sampled from 29748 SNPs. The results showed that the estimates of heritability generally decreased when the number of SNPs reduced. There were relatively high phenotypic and genetic correlations between the pairs of BWT, BL, BH, BWH and EW, which indicated that genetic improvement for these traits could be accomplished merely by selecting one trait. The results obtained in this study may provide a reference for the later selective breeding programme.