Selection of a new scallop strain, the Bohai Red, from the hybrid between the bay scallop and the Peruvian scallop

Abstract

In our previous studies, inter-specific hybrid F1 with significant heterosis in growth was produced by hybridizing the bay scallop, Argopecten irradians irradians with the Peruvian scallop, A. purpuratus. However, due to the hermaphroditic nature of the two Argopecten scallops, it is difficult to produce the hybrid seed at large scales. To efficiently utilize the genetic resources of the two scallops, this study aimed to breed a new scallop strain from the hybrids. The key step in the selection was the breeding of the F1 generation from the hybrid cohort, most of which were both male- and female-sterile. A small cohort of F1 with normal male- and female-fertility was produced through mass spawning of a large cohort of hybrids. The F2–F6 cohorts were reproduced with size- and color-selected brood stocks from the F1–F5 cohort, respectively. The results showed that, compared with the control bay scallop cohorts, the average shell height, average whole body weight and average adductor muscle weight were increased by 15.6%, 37.9% and 40.7% in F1, by 14.7%, 33.9% and 43.6% in F2, by 14.1%, 33.1% and 38.4% in F3, by 11.7%, 38.8% and 49.3% in F4, by 12.2%, 37.9% and 53.8% in F5, by 18.5%, 42.6% and 75% in F6, respectively. After six generations of selection, the median lethal temperature range was expanded from 3.0–29.0°C in F1 to 0°C–29.1°C in F6, suggesting that the selected strain can be reared in most waters of China, especially in Bohai Sea and Yellow Sea. Thus, through continuous selection on size and color, we have obtained a superior strain from the hybrids between the bay scallop and the Peruvian scallop, which is named ‘Bohai Red’.