蛤仔回交家系建立及早期生长发育比较

Establishment of backcross families of Manila clam Ruditapes philippinarum and comparison of their early growth and development

2009年9月,作者以蛤仔(Ruditapes philippinarum)杂交家系HD(♀H×♂D)及其亲本家系H、D为材料,采取单对交配策略建立了B1F1(♀HD×♂H)、B2F1(♀D×♂HD)、B3F1(♀HD×♂D)和B4F1(♀H×♂HD)4个回交家系,并对各家系蛤仔早期生长发育进行比较。结果表明:家系间蛤仔的卵径、受精率、孵化率和初孵D形幼虫壳长差异不显著(P>0.05);浮游幼虫期,B1F1和B3F1家系幼虫生长速度显著快于B2F1和B4F1(P<0.05),9日龄时B2F1和B4F1幼虫存活率显著低于B1F1和B3F1(P<0.05);变态期,B2F1和B4F1家系幼虫表现出明显的变态时间延长、变态规格小型化和变态率低等近交衰退现象;稚贝期,B1F1和B3F1家系稚贝生长优势开始显现,而B2F1和B4F1家系稚贝生长和存活劣势依旧明显。综上可见以杂交F1(♀)为母本的B1F1和B3F1家系早期生长和存活性状显著优于以杂交F1(♂)为父本的B2F1和B4F1家系,因此在蛤仔回交育种中以杂交F1(♀)为母本更有利于选择。

Four backcross families （B1F1 （♀HD×♂H）, B2F1 （♀D×♂HD）, B3F1 （♀HD×♂D） and B4F1 （♀H×♂HD） of Manila clam Ruditapes philippinarum） were established in September, 2009. Phenotypic traits of these families were analyzed. No significant difference were detected in egg-diameter, fertilization rates, hatching rates, and D larval size among the families （/9〉0.05）. We found that the growth rates of BIF1 and B3F1, which were selected F1 （♀） as female parents were significantly higher than those of BEF1 and B4F1 selected F1 （♂） as male parents （P〈0.05）, at all the early growth stages, but the difference between B1F1, BaF1 and control line were not significant before 60 days （P〉0.05）. Comparing the survival rates of these families, B1F1 and BaF1, were also significantly higher than those of BEF1 and B4F1, while there was no significant difference between B1F1, BaF1 and control line throughout the early growth stages （P〉0.05）. Therefore, selecting FI （♀） as the female parent, and then conducting a backcross breeding appears to be an effective method for genetic improvement of Manila clam Ruditapes philippinayum.