缢蛏快长选育系早期生长性状的遗传参数估计

Heritability estimates for growth traits at the earlier stage of the fast-growth selected line of Sinonovacula constricta

采用平衡巢氏设计方法,按照1雄配2雌的方式,构建缢蛏7个半同胞家系和14个全同胞家系,分别测定各个家系60日龄、90日龄及150日龄的壳长、壳高。雄内雌间半同胞个体间具有较大的变异程度,存在显著的母性效应,故以父系半同胞组内相关法计算的狭义遗传力为缢蛏快长选育系生长性状遗传力的无偏估计值。60日龄、90日龄和150日龄壳长的狭义遗传力分别为0.298、0.541、0.574;60日龄、90日龄和150日龄壳高的狭义遗传力分别为0.139、0.519、0.518。壳长和壳高在3个日龄的遗传力属于中等遗传力水平,显示出较高的选择育种潜力。缢蛏幼贝壳长、壳高两个指标间的遗传相关和表型相关均为正相关(P<0.05)。60日龄、90日龄和150日龄壳长-壳高性状间遗传相关系数分别为0.980、0.755、0.942,表型相关系数分别为0.910、0.882、0.912。表明缢蛏幼贝期以壳长或者壳高作为选育参数进行选择育种,可达到改良缢蛏快长选育系生长性状的效果。

7 half-sib families and 14 full-sib families of razor clam（ Sinonovacula constricta） were obtained by the balance nest design in which each male mated with two females. The shell length and shell height of each family were measured on 60 d,90 d and 150 d post-hatch. The heritability of the growth traits of the fastgrowth selected line of S. constricta was estimated using the full-sib family＇s theories. Analysis of variance showed that maternal effect existed because the maternal genetic variance component estimates were all greater than those of paternal ones of each growth trait（ P〈0. 01）,so the heritability of paternal half-sib families estimates in the narrow sense were precise unbiased estimator of the fast-growth selected line of S. constricta.The estimates of narrow-sense heritability were 0. 298,0. 541 and 0. 574 for shell length 0. 139,0. 519 and 0. 518 for shell height at spat stage,respectively. All of them belonged to moderate heritability,showing a high potential for selective breeding. The estimates of genetic correlation coefficients were 0. 980,0. 755 and 0. 942,respectively. The estimates of phenotypic correlation coefficients were 0. 910,0. 882 and 0. 912,respectively. The study indicates that shell length or height should respond favorably to direct and indirect selection for the fast-growth selected line of S. constricta at spat stage.