太平洋牡蛎与葡萄牙牡蛎两亚种间杂交及其早期阶段生长与存活的杂种优势

利用山东青岛养殖的太平洋牡蛎(N)与汕头本地养殖的葡萄牙牡蛎(S)两个近缘种为亲本,采用正交设计建立了杂种组NS(N♂×S♀)和SN(S♂×N♀)与纯种组NN(N♂×N♀)和SS(S♂×S♀)4个不同的遗传组合,通过比较不同阶段(幼虫期、稚贝期、养成阶段)的生长和存活数据,研究了牡蛎近缘种间的杂种优势,目的为改良牡蛎的生产性状。结果表明,这两个近缘种之间杂交能够产生显著的杂种优势,杂交后代的生长与存活两个表型性状都得到改良。杂交组比近交组生长得快,杂种优势在幼虫期为37.44%,稚贝期为42.47%。杂交组也比近交组存活率高,8日龄幼虫存活率的杂种优势为76.80%、14日龄幼虫存活率的杂种优势可达107.70%,60、90和105日龄稚贝存活率的杂种优势分别为17.30%、15.62%和9.08%。研究表明,通过太平洋牡蛎和葡萄牙牡蛎两个近缘种间的杂交有望解决牡蛎养殖产业存在的育苗难、存活率低、生长慢、个体小等问题。

Hybridization between the two close related species Crassostrea gigas and C.angulata and heterosis for growth and survival at early stage of life history

The Pacific oyster Crossostrea gigas and the Portuguese oyster C.angulata are two close related species and are also two most important cultured oysters in China,which have been separately cultured in North and South China.In order to improve production by exploring heterosis,two hybrid groups of NS(N♂×S♀)and SN(S♂×N♀)and two purebred groups of NN(N♂×N♀)and SS(S♂×S♀)were established using a diallel cross design with the parents of the Pacific oyster from Qingdao of Shandong(N)and the Portuguese oyster from Shantou of Guangdong(S).The present results showed that hybridization between the two close related species was successful.Two production traits of growth rate and survival rate for hybrids were both improved,and significant heterosis for them was obtained.The hybrids grew faster than the purebreds,and heterosis for growth rate is 37.44% at larvae stage and 42.47% at spat stage,respectively.The hybrids also survived more than the purebreds,and heterosis for survival rate is 76.80% and 107.70% for larvae on day 8 and 14,and 17.30%,15.62% and 9.08%,for juveniles on day 60,90,and 105,respectively.Our study showed that some problems influencing oyster production such as difficult breeding seeds,lower survival rate,slower growth,and smaller size could be solved by cross breeding between the close related species.