海湾扇贝南部亚种闭壳肌质量的双性状选择效应

采用双性状选择方法在经群体继代大壳高选育的海湾扇贝(Argopecten irradians concentricus Say)南部亚种F₃养殖群体中进行闭壳肌定向选育, 以评价闭壳肌的选择效果和现实遗传力, 为海湾扇贝南部亚种育种提供理论依据。结果表明, 在以壳高为第一选择性状、体质量为第二选择性状、壳高选择压力为10%、体质量选择压力为1%情况下, 正、负向选择组、对照组在产卵量、受精率、孵化率、幼虫期壳长增长率、中培期存活率、成体各形态参数等方面的差异不显著(P>0.05); 在稚贝育成率、养成期存活率、成体各质量性状等方面均存在显著差异(P<0.05), 各指标值均呈现正向选择组>对照组>负向选择组; 正、负向选择组中, 体质量与闭壳肌质量均出现较高的现实遗传力, 且正向选择组高于负向选择组; 双性状选择时, 体质量与闭壳肌质量的当代遗传获得明显高于单性状选择结果。壳高和体质量对闭壳肌质量均具有密切的遗传相关, 任何一个性状的选择均可对闭壳肌质量产生显著影响, 双性状同时选择可对闭壳肌质量产生叠加效应, 使闭壳肌质量性状的遗传进展达到最大。

Effect of selection for two traits on the adductor weight of the bay scallop, Argopeten irradians concentricus (Say)

We evaluated the effect of selection for one or two traits on the adductor weight of the bay scallop, Argopecten irradians concentricus(Say).We used a cultured F₃ population that had been produced by continuous progeny selection. We tested the effect of selection for shell height (selection pressure =10%) and/or body weight (selection pressure =1%). There was no significant difference(P>0.05) in spawning, fertilization rates, hatching rates, the growth rate of larvae, the survival to the mid-cultivation period, and the morphology of adults between the positive selection group, negative selection group, and control group. However, there was a significant effect (P<0.05) on the survival rate of juveniles. The survival during the grow-out period, the body weight of adults, and the values for each of the traits in the positive selection group were highest in the positive selection group and lowest in the negative selection group. We observed high realized heritability in both the positive and negative selection group, though the value was higher for the positive selection group than the negative. The inheritance of body weight and adductor weight was higher when both traits were selected than a single trait. Our results suggest there is a genetic correlation among shell height, body weight, and adductor weight, such that selection for the two former traits will affect the adductor weight. Concurrent selection for the two traits appears to have an additive effect, which will likely increase the rate of selection for adductor weight and thereby increase the yield. Our results provide a theoretical basis for improved selective breeding of the scallop.