Estimates of Heritability for Growth and Shell Color Traits and Their Genetic Correlations in the Black Shell Strain of Pacific Oyster Crassostrea gigas

Abstract

The Pacific oyster Crassostrea gigas has been introduced widely and massively and became an economically important aquaculture species on a global scale. We estimated heritabilities of growth and shell color traits and their genetic correlations in black shell strain of C. gigas. Analyses were performed on 22 full-sib families in a nested mating design including 410 individuals at harvest (24 months of age). The parentage assignment was inferred based on four panels of multiplex PCR markers including 10 microsatellite loci and 94.9% of the offspring were unambiguously assigned to single parent pairs. The Spearman correlation test (r = - 0.992, P < 0.001) demonstrated the high consistency of the shell pigmentation (SP) and L* and their same efficacy in shell color measurements. The narrow-sense heritability estimated under the animal model analysis was 0.18 ± 0.12 for shell height, 0.25 ± 0.16 for shell length, 0.10 ± 0.09 for shell width, 0.42 ± 0.20 for total weight, 0.32 ± 0.18 for shell weight, and 0.68 ± 0.16 for L*, 0.69 ± 0.16 for shell pigmentation, respectively. The considerable additive genetic variation in growth and shell color traits will make it feasible to produce genetic improvements for these traits in selective breeding program. High genetic and phenotypic correlations were found among growth traits and among shell color traits. To optimize a selection strategy for both fast growth and pure dark shell strain of C. gigas, it is proposed to take both total weight and black shell as joint objective traits in selective breeding program. Our study offers an important reference in the process of selective breeding in black shell color stain of C. gigas and will facilitate to develop favorable breeding strategies of genetic improvements for this economically important strain.

Genomic Selection for Growth Traits in Pacific Oyster (Crassostrea gigas): Potential of Low-Density Marker Panels for Breeding Value Prediction

“…Other studies have reported heritability estimates for weight ranging from 0.1 to 0.5 in C. gigas ( Hedgecock et al, 1991 ; Sheridan, 1997 ; Langdon et al, 2003 ; Evans and Langdon, 2006 ). Our results are consistent with heritability estimates described for shell measurements, e.g., Li et al (2011) reported values of 0.149–0.402 for SH in C. gigas at 12 months of age, while Kong et al (2015) described estimates of 0.49 for SH and 0.36 for SL, and Xu et al (2017) reported heritability values of 0.18 for SH and 0.25 for SL. These results imply that growth can potentially be improved by selective breeding.…”

Genome-wide association and genomic prediction of growth traits in the European flat oyster (Ostrea edulis)

“…Consistent with similar studies carried out in related oyster species (Xu et al 2017;Vu et al 2020), heritability estimates based on SNP markers were higher for total weight than for growth-related morphometric traits (i.e. shell height, shell width and shell length).…”

“…shell height, shell width and shell length). The estimation of heritability for total weight (herein referred to as TW) was similar to those reported for nine-month-old Portuguese oysters (ℎ 2 = 0.45) and a two-year old Pacific oyster strain (ℎ 2 = 0.42) (Vu et al 2021b;Xu et al 2017). Total weight, as measured in this study, is a composite phenotype made up of the animal's shell and soft tissue weights, in addition to the weight of any pallial fluid -thus is not a direct reflection of meat yield.…”

Seeking the perfect oyster shell: a brief review of current knowledge

“…), near‐black (h 2 = 0.52 ± 0.20 to 0.69 ± 0.16; Xu et al . ), and even purple, which was identified in some studies (see Song et al . for details on genetic differentiation).…”