大菱鲆(Scophthalmus maximus)耐高温和生长性状的遗传参数评估

Evaluation of genetic parameters for heat tolerance and growth traits in turbot (Scophthalmus maximus)

中文关键词: 大菱鲆(Scophthalmus maximus)  耐高温性状  遗传力  遗传相关

英文关键词: Turbot (Scophthalmus maximus)  Heat tolerance trait  Heritability  Genetic correlation

中文摘要:

      近年夏季高温期长使得培育耐高温良种成为大菱鲆养殖业的迫切需求。为评估大菱鲆耐高温性状遗传参数,本研究对来自30个家系的900尾大菱鲆进行高温胁迫实验,使用4种模型(LAM、CLAM、CTAMl和CTAMp)拟合了2种耐高温性状(耐热性上限性状,UTT;二元死亡存活性状,BTS),并用约束最大似然法(REML)估算方差组分。经分析,大菱鲆耐高温性状遗传力为0.110~0.208,属中低等遗传力性状。其中,利用线性模型(LAM和CLAM)估算的遗传力分别为0.110±0.074和0.155±0.082,利用阈值模型(CTAMl和CTAMp)估算的遗传力分别为0.214±0.072和0.208±0.074。表明可以通过遗传选育提高大菱鲆耐高温能力。两种耐高温表型性状与体重的遗传相关分别为-0.07±0.40和-0.13±0.33,表型相关分别为-0.04±0.05和-0.08±0.11,两种相关均为极低相关。不同模型估算的育种值(EBVs)进行相关性分析的结果显示,不同模型拟合同种耐温表型时,EBVs之间的相关系数 > 0.97,属于高强度正相关,表明使用同种表型定义时,线性或阈值模型对EBVs排名影响较小。不同模型估算EBVs与不同表型进行相关性分析的结果显示,阈值模型(CTAMl和CTAMp)估算的EBV与表型BTS之间的相关系数高于线性模型(LAM和CLAM),说明表型BTS比表型UTT更适合作为耐温性状。此外,在线性模型中使用UTT和BTS估算的EBVs之间的相关系数 < 0.50,说明采用2种表型定义下估算的大菱鲆耐高温性状的EBVs排名不一致,表明大菱鲆耐高温性状使用表型BTS和截面阈值动物模型(CLAMl或CTAMp)估算大菱鲆耐高温遗传参数更有优势。本研究结果补充了大菱鲆耐温性遗传参数研究,为制订冷水鱼类耐高温性状育种规划提供了理论依据。

英文摘要:

      Turbot (Scophthalmus maximus), belongs to the Scophthalmidae family and Scophthalmus genus. It is one of the most economically valuable aquaculture flatfish species in the world. The species is widely distributed in the Mediterranean, Black Sea and Baltic Sea. my country has made great progress in the introduction of turbot over the past 30 years, but there are still some urgent problems to be solved in order to further promote the industrial development of turbot aquaculture. Turbot is a cold-water fish with strict requirements on environmental temperature, so it is particularly susceptible to temperature stress. In the turbot aquaculture area in North China, the natural seawater temperature will exceed 26℃ throughout the summer (May to September), which is not suitable for turbot aquaculture during this period. Therefore, in order to solve this thorny problem, genetically improving the heat tolerance of turbot is of great significance to promote the sustainable and stable development of the turbot industry. In this study, we estimated the genetic parameters of heat resistance and growth traits of turbot. Thirty full-sib families were constructed by male-female pairing, with an equal weight of about 25 g, and heat resistance experiments were carried out. Thirty turbot were selected from each of the 30 families, totaling 900 individuals, for large-scale heat stress experiments. In order to evaluate the genetic parameters of high temperature tolerance traits in turbot, a high temperature stress experiment was conducted on 900 turbots from 30 families. Four models (LAM, CLAM, CTAMl and CTAMP) were used to fit two high temperature tolerance traits (upper limit trait of heat tolerance, UTT; binary death survival trait, BTS), and the variance components were estimated by the restricted maximum likelihood method (REML). The heritability of high temperature tolerance traits in turbot was 0.110-0.208, which was a medium-low heritability trait. Among them, the heritability estimated by linear models (LAM and CLAM) was 0.110±0.074 and 0.155±0.082, respectively, and the heritability estimated by threshold models (CTAMl and CTAMP) was 0.214±0.072 and 0.208±0.074, respectively. This shows that the high temperature tolerance of turbot can be improved through genetic selection. The genetic correlations of the two heat-resistant phenotypic traits with body weight were -0.07±0.40 and -0.13±0.33, respectively, and the phenotypic correlations were -0.04±0.05 and -0.08±0.11, respectively, both of which were extremely low correlations. The results of correlation analysis of breeding values ??(EBVs) estimated by different models showed that when different models fitted the same heat-resistant phenotype, the correlation coefficient between EBVs was > 0.97, which was a high-intensity positive correlation, indicating that when the same phenotypic definition was used, the linear or threshold model had little effect on the ranking of EBVs. The results of correlation analysis of EBVs estimated by different models and different phenotypes showed that the correlation coefficient between EBVs estimated by threshold models (CTAMl and CTAMP) and phenotypic BTS was higher than that of linear models (LAM and CLAM), indicating that phenotypic BTS was more suitable as a heat-resistant trait than phenotypic UTT. In addition, the correlation coefficient between the EBVs estimated by UTT and BTS in the linear model was < 0.50, indicating that the ranking of EBVs estimated by the two phenotypic definitions for the heat tolerance of turbot was inconsistent, indicating that it is more advantageous to use phenotypic BTS and cross-sectional threshold animal model (CLAMl or CTAMP) to estimate the genetic parameters of heat tolerance of turbot. The results of this study supplement the research on genetic parameters of heat tolerance of turbot and provide a theoretical basis for the formulation of breeding planning for heat tolerance traits of cold-water fish.