墨西哥湾扇贝与华贵栉孔扇贝的远缘杂交

Reciprocal crosses between Argopecten irradians concentricus and Chlamys nobilis

为进一步研究扇贝属间远缘杂交的可行性,以墨西哥湾扇贝(Argopecten irradians concentricus)与华贵栉孔扇贝(Chlamys nobilis)作为亲本,建立了两种扇贝的正交组MH、反交组HM、墨西哥湾扇贝自交组MM和华贵栉孔扇贝自交组HH。对各实验组的胚胎发育速度、受精率、孵化率、D形幼虫发生率和幼虫生长速度进行比较,分析了不同温度、盐度和精子浓度对各实验组配子亲和力及合子育性的影响,并尝试运用BP神经网络模型预测杂交组浮游幼虫的生长趋势。结果表明,两种扇贝的正反杂交均可获得早期杂交子代(F_1)。从胚胎发育情况看,正反杂交组幼虫发育到D形幼虫的时间均少于两个自交对照组;其受精率、孵化率、D形幼虫发生率也低于两个自交对照组;即使在不同温度、盐度和不同精子浓度下正反交组的受精率和孵化率也均低于两个自交组。从浮游幼虫生长情况看,正反交组D形幼虫的壳长和壳高均高于两个自交组,具有显著的差异性(P<0.01),表现出较明显的杂种优势。运用BP神经网络模型对正反交组的浮游幼虫进行预测,其预测值与实测值的误差率均小于4%。

In this study, two scallops, Argopecten irradians concentricus and Chlamys nobilis, were used to inves- tigate the possibility of intergeneric distant hybridization in scallops. Using A. irradians concentricus as the fe- male parent and C. nobilis as male parent, we established four experimental groups--an orthogonal group MH, a reciprocal group HM, an A. irradians concentricus inbred group MM, and a C. nobilis inbred group HH--to in- vestigate the fertilization, early development, and growth and survival of reciprocal crosses between the two scal- lops. The results show that reciprocal crosses ofA. irradians concentricus and C. nobilis can derive hybrids. For reciprocal cross groups MH and HM, the time required for the embryos to develop into D-shaped larva was less than that required for embryos in the inbred groups MM and HH （MH 18 h, HM 19 h, MM 21 h, and HH 22 h）. The average fertilization rate and average hatching rate of the MH and HM groups were lower than those of the MM and HH groups. Under different temperature, salinity, and sperm concentration, the fertilization rate and hatching rate of reciprocal cross groups MH and HM were lower than those of the MM and HH groups. A com- parison of the growth of planktonic larvae among four experimental groups from day 2 to day 11 revealed that the shell length and height of the MH and HM groups were significantly higher than those of the MM and HH groups, with both showing obvious heterosis （P〈0.01）. Experiments designed to predict the larvae of the orthogonal and rec-iprocal groups on the basis of the inbred group in shell length and height revealed that the growth tendency of hybrid scallop can be predicted using the BP neural network model method, and the error rate of the predicted values was less than 4%.