牙鲆选育 F3代家系的建立及遗传效应分析

摘要

牙鲆是太平洋西岸海水养殖、捕捞和自然增殖的主要鱼类，但是人工养殖病害多、生长慢，针对这一问题，从2003年开始开展了牙鲆选择育种。本文利用筛选和培育的 F1、F2代牙鲆家系核心群体，构建了 F3代家系52个，在生长到196 d 时，对家系1560尾鱼苗全长、体宽、体质量、全长日增量和体质量日增量5个生长性状进行测量和计算，获得7800个数据。采用“加性－显性”线性模型、最小范数二阶无偏估计法（MINQUE）对以上生长性状的边际平均值、加性方差分量、显性方差分量、随机方差分量、狭义遗传力、广义遗传力、亲本加性效应、杂交随机效应等遗传参数进行了评估。结果显示：1202、1206、1226和1211家系以上生长性状的边际平均值同时显著高于其他家系。以上5个生长性状的加性方差分量比率为（0．099±0．01）～（0．24±0．02），显性方差分量比率为（0．30±0．02）～（0．31±0．02），随机方差分量比率为（0．48±0．02）～（0．61±0．01），5个性状狭义遗传力为0．099～0．24，广义遗传力为0．38～0．54，以上遗传参数均达极显著性水平（p ＜0．01）。综合比较18个亲本5个性状的加性效应预测值，发现 F0917、F0908、F0905、F0915、F09125和 KS（韩国牙鲆）亲本在 5个性状上都具有极显著的正向效应（p＜0．01），其他亲本5个性状都不同程度的表现为显著（p ＜0．05）或极显著（p＜0．01）的负向加性效应。对42个杂交组合显性随机效应进行预测，D（2×6）、D（2×18）、D （3×4）、D（7×12）、D（7×14）和 D（8×13）6个杂交组合在 5个性状上都表现为极显著（p ＜0．05）正效应，利用这些杂交组合建立家系将促进牙鲆以上5个性状的生长。本文研究结果，为牙鲆优良家系的建立及新品种的培育初步筛选出了性状优良的亲本、杂交组合和家系，同时为牙鲆进一步选择育种提供了理论和技术依据。%Paralichthys olivaceus is the major species for marine aquaculture and fisheries on the western Pacific coast.Due to the high disease incidence and slow growth rate observed in artificial-breeding programs,the selective breeding of Japanese flounder has been pursued since the beginning of this century.Here,we established 52 F3 families based on the screened F1 and F2 core families that we bred previously.Approximately 196 days after hatching,we measured five growth traits of 1 560 fry from the 52 families,for a total of 7 800 data points.An “A-D”model and MINQUE were used to estimate the marginal mean,additive-variance component,dominance-vari-ance component,random-variance component,narrow-sense heritability,broad-sense heritability,parental additive effect and random hybridization effect of each trait.The additive-variance component ratios of the five traits were between (0.099±0.01)and (0.24±0.02);the dominance-variance component ratios were between (0.30±0.02) and (0.31±0.02);the random-variance component ratios were between (0.48±0.02)and (0.61 ±0.01);the narrow-sense heritabilities were between 0.099 and 0.24;and the broad-sense heritabilities were between 0.38 and 0.54.Each of these genetic parameters showed highly significant differences (p <0.01).The random dominance effects of 42 crosses were predicted,and D(2×6),D(2×18),D(3 ×4),D(7 ×12),D(7 ×14)and D(8×13)all showed highly significant positive effects (p<0.01)on the five traits.The results of this study provide a prelimi-nary set of optimal parental lines,crosses and families to establish improved Japanese flounder strains.These re-sults also provide a theoretical and technical foundation for further selective breeding.