Interspecific hybridization between Patinopecten yessoensis (♀) and P. caurinus (♂) with heterosis in growth and temperature tolerance

Hybridization is a powerful tool for improving productivity and profitability in aquaculture. To determine the performance characteristics of Patinopecten scallop hybrids, complete diallel hybridizations were carried out between Yesso scallops (P. yessoensis) and Weathervane scallops (P. caurinus) (Py♀ × Pc♂; Pc♀ × Py♂), together with intraspecific scallops P. yessoensis (Py♀ × Py♂) and P. caurinus (Pc♀ × Pc♂). The Pc♀ × Py♂ cohort only survived until 21 days after fertilization, while the Py♀ × Pc♂ cohort outperformed both purebred parental cohorts in larval, juvenile and adult growth periods with higher growth and survival rates. In particular, the growth rate of the Py♀ × Pc♂ cohort was significantly higher than that of the parental scallops at the adult grow-out stage. Compared with those in the Yesso scallops, the production traits in the Py♀ × Pc♂ cohort were increased by 16.43% in shell height and 26.87% in whole body weight, with heterosis of 21.6 and 34.9, respectively. Moreover, the survival rate of Py♀ × Pc♂ cohort adult hybrids (46.2 ± 3.2%) was notably higher than that of Yesso scallops (28.5 ± 4.5%) and Weathervane scallops (18.4 ± 5.2%) after thermal duress in summer and cold endurance in winter, showing significantly higher heterosis (97.0). Nuclear sequence (internal transcribed spacer) and mitochondrial DNA sequence (16S rDNA) analyses confirmed that the derived hybrid adults (Py♀ × Pc♂) were true hybrids between the two Patinopecten scallops. Our data presented evidence that artificially interspecific hybridization between P. yessoensis and P. caurinus was experimentally possible and achieved considerable heterosis of the Py♀ × Pc♂ cohort in growth performance and temperature tolerance. The hybrid adults (Py♀ × Pc♂) may provide valuable germplasm resources for increasing scallop production and support the development of strategies for long-term healthy sustainable aquaculture.