The growth, survival and ploidy of diploid, triploid and tetraploid of the Pacific oyster (Crassostrea gigas) in larval and juvenile stages

Slow growth and genomic instability are the main problems facing tetraploid oyster breeding. In response to the above problem, we developed tetraploid by using Crassostrea gigas ‘Haida No.3’, a new variety with rapid growth and black shell color, and analyzed the growth, survival and ploidy of diploid ♀ × diploid ♂ (DD), diploid ♀ × tetraploid ♂ (DT: triploid) and tetraploid ♀ × tetraploid ♂(TT) in different periods. The results showed that there was no significant difference between the fertilization rate of DD, DT and TT, but the hatching rate of TT was significantly lower than that of DD (P < 0.05). The shell height of TT was significantly lower than DD, and the shell height of DT was significantly higher than that of DD at 13 days (P < 0.05). The survival rate of TT was lower than that of DD and DT in larval stage (P < 0.05), while there was no significant difference in the mean survival rate of DD, DT and TT in juvenile stage. The tetraploid rate in TT was 100% during the larval and juvenile stages. The shell color of all progeny in TT and DT was black and consistent with C. gigas ‘Haida No.3’. These results indicated that black shell color of C. gigas ‘Haida No.3’ could be stably passed on to triploid and tetraploid offspring, suggesting that establishing genomically stable tetraploid populations was feasible by screening tetraploid parents.