壳金长牡蛎自交和杂交家系生长与存活比较

选择具有生长优势的长牡蛎(Crassostrea gigas)G2(A)家系及具有明显生长和存活优势的G19(B)和G28(C)家系进行完全双列杂交,得到包括3个自交组(AA、BB、CC)和6个杂交组(AB、AC、BA、BC、CA、CB)共9个壳金长牡蛎实验组,分析各实验组在幼虫期及稚贝期不同日龄的各生长指标和存活性能,并评估了杂交组的杂种优势。结果表明,在整个培育阶段,大多数杂交组在不同生长时期均表现出较高的生长和存活性能,其中,浮游幼虫期5日龄,所有杂交组的壳高和壳长均显著大于自交组(P0.05);10日龄后,杂交组CB、BC和AC的壳高显著大于相应的自交组(P0.05),杂种优势明显;稚贝期85和130日龄,杂交组CB的壳高性能大于其他实验组。浮游幼虫期10日龄,CB组存活率显著大于AA、CA组(P0.05);稚贝期85日龄后,杂交组AC、CA和CB的存活率杂种优势逐渐增大;190日龄,杂交组AC、BC与自交组AA、CC之间存活率差异显著(P0.05)。研究结果为壳金长牡蛎新品种的培育及杂种优势的充分利用奠定了重要基础。

Comparison of growth and survival of the hybrid and inbred families in the golden shell color strain of Pacific oyster (Crassostrea gigas)

The Pacific oyster (Crassostrea gigas) is one of the most important cultured bivalve species in the world. Given that oysters with golden shell coloration are rarely seen in the market and are sold at much higher prices than others, developing the golden shell line ofC. gigasto have enhanced growth traits and survival rates is of great consequence. A series of 3′3 diallel crosses of three full-sib inbreeding families in the golden shell color strain ofC. gigas of G2(A) with better growth performance and G19(B) and G28(C) with better growth and sur-vival performance was conducted, including three inbreeding groups (AA, BB, CC) and six hybrid groups (AB, AC, BA, BC, CA, CB). Growth performance, survival rate and heterosis were evaluated and compared at larval and juvenile stages between different groups. The results showed that most of the hybrid groups presented better growth performance and survival rate than their inbreeding groups at different stages. At the larval stage of day 5, the larval shell height and shell length of all the hybrid groups were significantly greater than the inbreeding groups (P<0.05). At days 10, 15 and 20, the shell height and shell length of the CB and BC groups were out-standing: the differences between them and their corresponding inbreeding groups were significant (P<0.05), and the heterosis was obvious. At day 10, the larval survival rate of CB was significantly greater than AA and CA(P<0.05). The heterosis of larval shell height, shell length and survival rate among all hybrid groups were be-tween 1.88% and 14.24%, 0.28% and 14.67% and 10.72% and 23.22%, respectively. At the juvenile stage, each group also showed differences in growth and survival characteristics, and the three growth traits and survival rate of hybrid groups showed different heterosis. At days 85 and 130, the shell height of hybrid group CB was greater than the other experimental groups. The heterosis of the survival rate of AC, CA and CB groups showed a clear trend to increase with age. At day 190, the juvenile survival rate of AC and BC was significantly greater than AA and CC (P<0.05). The heterosis of the juvenile shell height, shell length, total weight and survival rate was be-tween 11.04% and 9.42%, 11.59% and 13.98%, 3.85% and 27.99% and 3.60% and 12.63%, respectively. All re-sults were consistent with those of the larval stage, showing bad constancy and balance. This result provides an important basis for genetic improvement and better utilization of heterosis of the golden shell color strain of C. gigas.