Feasibility of interspecific hybridization between Iwagaki oyster, Crassostrea nippona and Portuguese oyster, Crassostrea angulata

Iwagaki oyster, Crassostrea nippnoa is famous for its unique flavor and delicacy, while the Portuguese oyster, C. angulata has become an important oyster species in aquaculture because of its high growth rate and high market demand. For the first time, 2 x 2 factorial hybridization between them was performed, forming four groups, including C. nippona female x C. nippona male (NN), C. nippona female x C. angulata male (NA), C. angulata female x C. nippona male (AN), C. angulata female x C. angulata male (AA). The results showed that fertilization only occurred in NA, not in AN. The cleaved rate, D larvae rate and larvae survival level of NA were remarkably lower than those of the two pure parent groups, but the survival rate of NA and NN was comparable during the grow out stage. NA has no growth heterosis in larval stage, but has obvious growth heterosis in growth stage. On 360th day, the mid-heterosis of NA was 10.76 for shell height, and 26.60 for wet weight, respectively. Like the progenies of pure parents, the gonads of NA hybrids develop normally and can produce gametes. The shell morphology of NA was similar to that of NN and has a strong maternal effect. These results demonstrate that the eggs of C. nippona can be fertilized with the sperm of C. angulata through one way fertilization, and can produce viable hybrids with growth heterosis at the grow-out stage. NA hybrids have good application potential in aquaculture.

Automated summary

The Iwagaki oyster and Portuguese oyster are two oyster species with different advantages. By hybridizing them, a breeding variety with growth heterosis can be obtained.