Selection of a carotenoid-rich scallop strain, QN Orange, from the inter -specific hybrids between the bay scallop and the Peruvian scallop

In our previous study, we reported the selection of 'Bohai Red', a new scallop strain with improved performance in growth from the hybrids between the bay scallop and the Peruvian scallop. In this study, we selected another new strain, the 'QN Orange' scallop, with orange adductor muscles, from the same hybrid cohort as the origin of 'Bohai Red'. In brief, during the selection of the 'Bohai Red' strain, a small F1 cohort was produced through mass spawning of a large cohort of the bay scallop-Peruvian scallop hybrids and reproduced consecutively to obtain the F2-F3 cohorts with size-selected brood stocks. About 500 scallops with orange adductor muscles and shells were selected from the F3 selection cohort to form the base selection cohort (G0). The G1-G6 cohorts were reproduced with size-selected brood stocks with orange adductor muscles and orange shells from the G0-G5 cohorts, respectively. The results showed that the percentage of scallops with orange adductor muscles was 88.9% in G1, 92.3% in G2, 92.0% in G3, 94.9% in G4, 96.6% in G5 and 97.4% in G6, respectively. No significant difference in growth was found between the new selection cohort and the control 'Bohai Red' selection cohort, however, compared with the control bay scallop cohort, the average shell height, whole weight and adductor muscle weight of the new selection strain were 4.5%, 30.4% and 16.3% higher in G1, 4.1%, 40.6% and 65.2% higher in G2, 20.3%, 50.3% and 88.9% higher in G3, and 17.7%, 73.9% and 80.8% higher in G4, respectively. Thus, through continuous selection, we have obtained a new scallop strain with orange adductor muscle/orange shell and improved growth from the bay scallop-Peruvian scallop hybrids, which was named 'QN Orange' scallop.