牙鲆(Paralichthys olivaceus)家系生长性状遗传效应分析

牙鲆(Paralichthys olivaceus)优良养殖新品种培育是防止其品种退化和提高经济效益的主要途径,数量性状遗传评估是牙鲆育种的主要方法之一.本研究利用已建立的牙鲆核心群体建立42个牙鲆家系,分别测量140、170、200、380日龄各家系生长相关性状(体重、全长和体宽),通过MINQUE、REML和BLUP方法对其进行数量遗传分析.结果显示,不同时期生长性状的变异系数为10.56％-38.62％,其中,体重的变异系数最大,全长和体宽的变异系数都较小,不同性状的变异系数均随着日龄的增加而减小.3个性状的加性方差分量比率为(0.13±0.01)-(0.29±0.06),随机方差分量比率为(0.71±0.06)-(0.87±0.01),狭义遗传力为(0.13±0.01)-(0.29±0.06),广义遗传力为(0.15±0.01)-(0.54±0.06),以上遗传参数均达极显著性水平(P＜0.01).综合比较3个性状在不同时期的遗传效应,结果发现,F0990、F1005、KS和F0719这4个群体亲本都为极显著正向效应,F0751、F0768、F0780、F09121、F0927和RS这6个群体亲本都为极显著负向效应(P＜0.01),其余的亲本均为一般效应.表型相关系数在0.82-0.96之间,遗传相关系数在0.72-0.97之间.利用BLUP方法对380日龄测量的数据进行育种值估算,结果发现,亲鱼体重育种值为14.63-100.05,其中,体重育种值最高的亲鱼个体为F1005-8、F09119-11、F09125-4、F0915-57、F09104-12、F1264、F0908-38、F0927-20、F1005-53、F0990-6、F09125-7、F0751-14和F1005-42.家系平均体重育种值为20.87-35.60,其中,平均体重育种值最高的家系为F1416、F1428、F1442、F1418、F1427、F1408、F1402、F1412和F1446.以体重育种值为依据选留的家系育种值与根据表型值选留的家系育种值比较可得:体重育种值选择比其表型值的选择效率高81.91％,育种值选育更好.本研究为牙鲆优良家系的建立及新品种的培育筛选出了性状优良的亲本和家系,同时为牙鲆育种计划的制定提供了重要理论依据.

Genetic Effect Analysis of Growth Traits in Paralichthys olivaceus Families

Breeding new varieties is a main approach to prevent the genetic degradation and improve traits for the purpose of economic benefits.Quantitative genetics evaluation is one of the main methods used in Japanese flounder (Paralichthys olivaceus) breeding.By using the core populations from the established breeding program,this research evaluated three growth related traits (body weight,total length,and body width) among 42 newly-generated families on 140 d,170 d,200 d (before mixing pool) and 380 d (after mixing pool).The quantitative genetic analysis was carried out using MINQUE,REML and BLUP.The results showed that the variation coefficient of growth traits ranged between 10.56％ and 38.62％ at different day age.Among three growth traits,the variation coefficient was the largest in body weight,and was relatively small in total length and body width.The variation coefficient of different traits decreased with the increase of day age.The additive variance component ratio for the three traits was between (0.13±0.01) and (0.29±0.06),whereas the random variance component ratio was between (0.71±0.06) and (0.87±0.01).By contrast,the narrow sense heritability ranged between (0.13±0.01) and (0.29±0.06) and the generalized heritability was from (0.15±0.01) to (0.54±0.06).All of the above genetic traits were highly significant (P＜0.01).Comparison of genetic effects on three growth traits during different developmental stages revealed that four parental groups (F0990,F 1005,KS,and F0719) showed significant positive effects,whereas six groups of parental groups (F0751,F0768,F0780,F09121,F0927,and RS) showed significant negative effect (P＜0.01).By contrast,the rest of 32 parental samples showed no significant effect.The correlation coefficient was between 0.82 and 0.96 in phenotype and between 0.72 and 0.97 in genotype.The phenotypic and genetic correlation coefficient of different day ages were maintained at a relatively stable level.Breeding value of the 380-day age was estimated using the BLUP method.The results showed that breeding value of the parental fish body weight was between 14.63 and 100.05.Among all the families,the highest breeding values for body weight were found in F1005-8,F09119-11,F09125-4,F0915-57,F09104-12,F1264,F0908-38,F0927-20,F1005-53,F0990-6,F09125-7,F0751-14 and F1005-42,average between 20.87 and 35.60.The families with the highest average weight breeding value were F1416,F1428,F1442,F1418,F1427,F1408,F1402,F1412 and F1446.Compared with the method of phenotypic selection,the breeding values obtained from growth-based selection were better for improving growth traits since the selection efficiency was up to 81.91％.In this study,parents and families with superior growth traits were selected to improve the genetic quality and new varieties of P.olivaceus.Meanwhile,it provides an important theoretical basis for the development of P.olivaceus breeding program.