An estimation of genetic parameters of growth traits in juvenile turbot (Scophthalmus maximus L.) using parental molecular relatedness

The estimation of genetic parameters has played an important role in animal selective breeding for growth traits.Recently studies show that molecular markers can be incorporated into genetic evaluations. In order to improve the performance of an incomplete pedigree（i.e, only parents are known） in the genetic evaluations, 12 microsatellite markers have been applied in the estimation of the genetic parameters for body weight in a farmed population（n=1 890） of juvenile turbot（Scophthalmus maximus L.）. A new relatedness called parental molecular relatedness（PMR） is estimated based on results of genotyping of 48 parents（31 males, 17 females） with microsatellites markers. The feasibility of PMR in estimation of genetic parameters is verified by comparison with pedigree related（PR） which is obtained from a complete pedigree. The results demonstrate that a high correlation（0.872） between them is found. Heritabilities are estimated using the PMR（0.52±0.13） and PR（0.55±0.22） with the same animal model. A cross-validation shows that the predictive abilities of models using the PMR and the PR are identical（0.81）. From that, a conclusion can be made that PMR and PR predicted genetic values equally well in a population of juvenile turbot. Therefore PMR can be applied as an alternative of the PR when only parents are known. However, for a better performance, more markers and more families should be included in a further study.

Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus trees.Height,DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model analysis.Significant site and family effects on the three traits were observed.The distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable conditions.Growth differences by family was significant,emphasizing the importance of identifying families with either superior or inferior performance.The parental ranking was assigned in the sites,inferring the breeding value of each plus tree.The estimates of individual heritability(h_(i)^(2))of height,DBH and volume growth were 0.169-0.645,0.108-0.331 and 0.129-0.343 respectively,with higher h_(i)^(2) of the height than DBH on each site.Coefficient of variance of genetic effect was higher with DBH in some cases,indicating the scope for selection is larger for this trait despite the lower heritability compared to height.For the variation between families in terms of the performance stability across sites,consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine.A few families with either superior or inferior performance retained their parental ranking for at least a decade.Other families with increased growth on a particular site were identified,indicating their high breeding value and low stability.Differences in the genetic performance of the families by site requires delineation of the breeding region of the species.

Genetic parameters for somatic cell score and production traits in the fi rst three lactations of Chinese Holstein cows

The objectives of this study were to estimate genetic parameters of lactation average somatic cell scores （LSCS） and examine genetic associations between LSCS and production traits in the first three lactations of Chinese Holstein cows using single-parity multi-trait animal model and multi-trait repeatability animal model. There were totally 273605 lactation records of Chinese Holstein cows with first calving from 2001 to 2012. Heritability estimates for LSCS ranged from 0.144 to 0.187. Genetic correlations between LSCS and 305 days milk, protein percentage and fat percentage were -0.079, -0.082 and -0.135, respectively. Phenotypic correlation between LSCS and 305 days milk yield was negative （-0.103 to -0.190）. Genetic correlation between 305 days milk and fat percentage or protein percentage was highly negative. Genetic correlation between milk fat percentage and milk protein percentage was highly favorable. Heritabilities of production traits decreased with increase of parity, whereas heritability of LSCS increased with increase of parity.

Genetic parameters of drinking and feeding traits of wean-to-finish pigs under a polymicrobial natural disease challenge

Background:The pork industry faces unprecedented challenges from disease,which increases cost of production and use of antibiotics,and reduces production efficiency,carcass quality,and animal wellbeing.One solution is to improve the overall resilience of pigs to a broad array of common diseases through genetic selection.Behavioral changes in feeding and drinking are usually the very first clinical signs when animals are exposed to stressors such as disease.Changes in feeding and drinking behaviors in diseased pigs may reflect the way they cope with the challenge and,thus,could be used as indicator traits to select for disease resilience.The objectives of this study were to estimate genetic parameters of feeding and drinking traits for wean-to-finish pigs in a natural polymicrobial disease challenge model,to estimate genetic correlations of feeding and drinking traits with growth rate and clinical disease traits,and to develop indicator traits to select for disease resilience.Results:In general,drinking traits had moderate to high estimates of heritability,especially average daily water dispensed,duration,and number of visits(0.44 to 0.58).Similar estimates were observed for corresponding feeding traits(0.35 to 0.51).Most genetic correlation estimates among drinking traits were moderate to high(0.30 to 0.92)and higher than among feeding traits(0 to 0.11).Compared to other drinking traits,water intake duration and number of visits had relatively stronger negative genetic correlation estimates with treatment rate and mortality,especially across the challenge nursery and finisher(−0.39 and−0.45 for treatment rate;−0.20 and−0.19 for mortality).Conclusion:Most of the recorded drinking and feeding traits under a severe disease challenge had moderate to high estimates of heritability,especially for feed or water intake duration and number of visits.Phenotypic and genetic correlations among the recorded feeding traits under disease were generally low but drinking traits showed high correlations with each other.Water intake duration and number of visits are potential indicator traits to select for disease resilience because of their high heritability and had moderate genetic correlations with treatment and mortality rates under severe disease.

Genetic parameters and trends for production and reproduction traits of a Landrace herd in China

The objectives of this study were to estimate the genetic parameters and the breeding progress in a Landrace herd in China, and to predict the potential benefits by applying new breeding technology. Hereby, the performance records from a Landrace swine herd in China, composing over 33 000 pigs born between 2001 and 2013, were collected on six economically important traits, i.e., average daily gain between 30-100 kg（ADG）, adjusted backfat thickness at 100 kg（BF）, adjusted days to 30 kg（D30）, adjusted days to 100 kg（D100）, number born alive（NBA）, and total number born（TNB）. The genetic parameters were estimated by restricted maximum likelihood via DMU, and realized genetic trends were analyzed. Based on the real population structure and genetic parameters obtained from this herd, the potential genetic trends by applying genomic selection（GS） were predicted via a computer simulation study. Results showed that the heritability estimates in this Landrace herd were 0.55（0.02）, 0.42（0.01）, and 0.12（0.01）, for BF, D100, and TNB, respectively. Favorable genetic trends were obtained for D100, BF, and TNB due to direct selection, for ADG and NBA due to indirect selection. Long-term selection against D100 did not improve D30, though they are highly genetically correlated（0.64）. Appling GS in such a swine herd, the genetic gain can be increased by 25%, or even larger for traits with low heritability or individuals without phenotypes before selection. It can be concluded that conventional breeding strategy was effective in the herd studied, while applying GS is promising and hence the road ahead in swine breeding.

Genetic parameters and response to selection for body weight in turbot(Scophthalmus maximus, Linnaeus)

Genetic parameters and response to selection were estimated for harvest body weight in turbot. The data consisted of 10 952 individuals of 508 full-sib families from three generations（G0, G1, and G2）. The heritability estimates for G0, G1, and G2 were 0.11±0.08, 0.18±0.09, and 0.17±0.07, respectively. Over three generations, the heritability estimate was 0.19±0.04. Maternal and common environmental effects were 0.10±0.04, 0.14±0.04, and0.13±0.03 within each generation and 0.12±0.01 across generations. The selection differential in growth was 18.24 g in G0 and 21.19 g in G1 corresponding to an average of 19.72 g per generation. The genetic gains were also calculated, they were 22.06 g in G1 and 11.93 g in G2, corresponding to 6.36% and 3.52% body weight. The total genetic gain after two generations was 10.10% body weight, which indicated that the selective breeding program for the body weight trait in turbot was successful.

A Method for Upscaling Genetic Parameters of CERES-Rice in Regional Applications

To upscale the genetic parameters of CERES-Rice in regional applications, Jiangsu Province, the second largest rice producing province in China, was taken as an example. The province was divided into four rice regions with different rice variety types, and five to six sites in each region were selected. Then the eight genetic parameters of CERES-Rice, particularly the four parameters related to the yield, were modified and validated using the Trial and Error Method and the local statistical data of rice yield at a county level from 2001 to 2004, combined with the regional experiments of rice varieties in the province as well as the local meteorological and soil data （Method 1）. The simulated results of Method 1 were compared with those of other three traditional methods upscaling the genetic parameters, i.e., using one-site experimental data from a local representative rice variety （Method 2）, using local long-term rice yield data at a county level after deducting the trend yield due to progress of science and technology （Method 3）, and using rice yield data at a super scale, such as provincial, ecological zone, country or continent levels （Method 4）. The results showed that the best fitness was obtained by using the Method 1. The coefficients of correlation between the simulated yield and the statistical yield in the Method 1 were significant at 0.05 or 0.01 levels and the root mean squared error （RMSE） values were less than 9% for all the four rice regions. The method for upscaling the genetic parameters of CERES-Rice presented is not only valuable for the impact studies of climate change, but also favorable to provide a methodology for reference in crop model applications to the other regional studies.

Estimation of the Genetic Parameters on Reproduction Performances of the China Yorkshire Line SⅡ_1

[Objective] This study was to investigate the genetic parameters on reproduction performances of China Yorkshire line SII,. [Method] Using China Yorkshire line SII, as experimental animal, its genetic parameters on reproduction performance, such as total number of born （TNB）, the alive number of born （ANB）, the litter weight of born （LWB） and the litter weight at age of 21 days （/W21 ） , were estimated by using the DFREML method of multi-traits animal model. [Result] The heritability estimates of TNB, ANB, LWB and LW21 were 0.11,0.19, 0.14 and 0.05, respectively; and the genetic correlations between the traits as TNB/ANB, TNB/LWB, TNB/LW21, ANB/LWB, ANB/LW21, LWB/LW21 were 0.91, 0.76, 0.65, 0.85, 0.59 and 0.38, respectively. [ Conclusion] Main genetic parameters of reproduction traits in China Yorkshire line all, have all reached or even exceeded the requirements of breeding.

Influence of parental sample sizes on the estimating genetic parameters in cultured clam Meretrix meretrix based on factorial mating designs

The precise and accurate knowledge of genetic parameters is a prerequisite for making efficient selection strategies in breeding programs.A number of estimators of heritability about important economic traits in many marine mollusks are available in the literature,however very few research have evaluated about the accuracy of genetic parameters estimated with different family structures.Thus,in the present study,the effect of parent sample size for estimating the precision of genetic parameters of four growth traits in clam M.meretrix by factorial designs were analyzed through restricted maximum likelihood（REML） and Bayesian.The results showed that the average estimated heritabilities of growth traits obtained from REML were 0.23-0.32 for 9 and 16 full-sib families and 0.19-0.22 for 25 full-sib families.When using Bayesian inference,the average estimated heritabilities were0.11-0.12 for 9 and 16 full-sib families and 0.13-0.16 for 25 full-sib families.Compared with REML,Bayesian got lower heritabilities,but still remained at a medium level.When the number of parents increased from 6 to 10,the estimated heritabilities were more closed to 0.20 in REML and 0.12 in Bayesian inference.Genetic correlations among traits were positive and high and had no significant difference between different sizes of designs.The accuracies of estimated breeding values from the 9 and 16 families were less precise than those from 25 families.Our results provide a basic genetic evaluation for growth traits and should be useful for the design and operation of a practical selective breeding program in the clam M.meretrix.

Estimating genetic parameters with molecular relatedness and pedigree reconstruction for growth traits in early mixed breeding of juvenile turbot

An introduced turbot population was used to establish families and to estimate genetic parameters of the offspring. However, there is a lack of pedigree information, and common environmental effects can be introduced when each full-sib family is raised in a single tank. Therefore, in the genetic evaluation, SSRs(simple sequence repeats) were used to reconstruct the pedigree and to calculate molecular relatedness between individuals, and the early mixed-family culture model was used to remove the impact of the common environmental effects. After100 d of early mixed culture, twenty SSRs were used to cluster 20 families and to calculate paired molecular relationships(n=880). Additive genetic matrices were constructed using molecular relatedness(MR) and pedigree reconstruction(PR) and were then applied to the same animal model to estimate genetic parameters. Based on PR, the heritabilities for body weight and body length were 0.214±0.124 and 0.117±0.141, and based on MR they were 0.101±0.031 and 0.102±0.034, respectively. Cross validation showed that the accuracies of the estimated breeding values based on MR(body weight and body length of 0.717±0.045 and 0.629±0.141, respectively) were higher than those of PR(body weight and body length of 0.692±0.052 and 0.615±0.060, respectively). The MR method ensure availability of all genotyped selection candidates, thereby improving the accuracy of the breeding value estimation.

Estimation of Genetic Parameters for Main Economic Traits in Keerqin Fine Wool Sheep

To investigate the population genetic structure of Keerqin fine wool sheep, the paternal half sib correlation method was employed to estimate the body weight traits, genetic and phenotypic correlation between fleece traits in the Keerqin fine wool sheep. The results showed that the correlation coefficients were 0.690 1, 0.593 1, 0.581 2, 0.210 2 for birth weight with weaning weight, body weight at one week of age, body weight at two week of age, and body weight at three week of age, respectively. The genetic correlations were highly significant （ P 〈0.01 ） for the four pairs of traits. The correlation coefficients were 0.373 3, 0.274 1, 0.268 2 for weaning weight with body weight at one week of age, body weight at two week of age, and body weight at three week of age, respectively. The genetic correlations were also extremely significant （ P 〈 0.01 ） for the three pairs of traits. The correlation coefficients were 0.712 0, 0.805 0, 0.717 1,0.701 9, 0.531 6, 0.719 0, 0.681 3 and 0.521 3 for wool fineness at one week and two week of age, wool fineness at one week and three week of age, staple length and fleece weight at one week of age, staple length at one week and three week of age, fleece weight at one week of age and wool fineness at three week of age, wool fineness at two week and three week of age, wool fineness at two week of age and fleece weight at three week of age, and fleece weight at two week and three week of age, respectively. The high genetic correlations were extremely significant （ P 〈0. O1 ） for the eight pairs of traits. The phenotypic correlations were generally lower than the genetic correlations.

Estimation of Genetic Parameters for Main Wool Traits in Keerqin Fine Wool Sheep

[Objective]To investigate the population genetic structure of Keerqin fine wool sheep. [Method]The genetic parameters of wool traits in Keerqin fine wool sheep were calculated by employing paternal half sib correlation method. [Results]The traits with high heritability( h≥0. 3) included wool length( 1-year old),wool yield( 1-year old) and wool yield( 2-year old); that with medium heritability( 0. 1≤h≤0. 3) included wool fineness( 1-year old),wool fineness( 2-year old),wool length( 3-year old) and wool yield( 3-year old). There were extremely significant positive correlations between wool fineness( 1-year old) and wool fineness( 2-year old),between wool fineness( 1-year old) and wool fineness( 3-year old),between wool length( 1-year old) and wool length( 2-year old),between wool length( 1-year old) and wool length( 3-year old),and between wool fineness( 2-year old) and wool fineness( 3-year old),with the correlation coefficients of 0. 653 0,0. 625 8,0. 489 6,0. 578 8,0. 578 4 and 0. 554 6 respectively. The results showed that the phenotypic correlation was poorer than genetic correlation among the wool traits. [Conclusion]The wool fineness,wool yield and body weight of Keerqin fine wool sheep all fail to meet the excellent level and need to be improved further.

Altitude shape genetic and phenotypic variations in growth curve parameters of Larix kaempferi

To study the effects of geoclimatic variables of provenances on growth phenotypes and selected plus provenances,over 3000 trees of 22-year-old Larix kaempferi were evaluated from trials established in two climate zones for provenance selection and to explore the influence of climate variables on provenance performance.The material was replicated plantings of 84 open pollinated families from six provenances distributed in the mountains of central Japan.Provenance variation was observed in most age groups and the heritability of growth traits showed large differences.The phenotypic maximum value of height and diameter were significantly positive with altitude,and mean annual precipitation being important factors.Diameter at breast height growth was significantly negative with altitude and spring rainfall.The Ina provenance of relatively high altitudes,was well adapted to a variety of climates.Altitude might be the driving force for phenotypic and genetic variations and local adaptation.

Estimationof genetic parameters for juvenile growth performance traits in oliveflounder(Paralichthys olivaceus)

The aim of this study was to evaluate genetic parameters of growth traits for improving selective breeding in olive flounder(Paralichthys olivaceus).A total of 82 full-sib families from 2 year-classes with complete pedigree information were used to estimate heritabilities and genetic/phenotypic correlations for 4 growth performance traits(body weight BW,total length TL,body height BH and condition factor K)based on uni-trait and multi-trait linear mixed models,respectively.Data were analyzed by the restricted maximum likelihood(REML)method.The heritabilities of BW,TL and BH were 0.81,0.70 and 0.61,which are relatively high,however,heritability for K is low(0.11).For all growth traits,the common full-sib effects(c^(2))were at a low to moderate level(0.14–0.20);the maternal effects(m^(2))of the traits(except K)were also detected(0.15–0.19).The phenotypic and genetic correlations among BW,TL and BH were highly positive(0.70–0.91),however,the correlations between K and the other 3 traits was low or negligible(−0.22–0.26).According to our results,these traits(except K)could be selected and enhanced simultaneously.In addition,direct selection based on TL or BH,which is an easily measurable trait,will be more favorable than selection on BW.Moreover,our results indicated that growth parameters estimated in the juvenile stage could be used as a predictor of growth performance at later growth stages.

Prediction of meat quality traits in the abattoir using portable near-infrared spectrometers:heritability of predicted traits and genetic correlations with laboratory-measured traits

Background:The possibility of assessing meat quality traits over the meat chain is strongly limited,especially in the context of selective breeding which requires a large number of phenotypes.The main objective of this study was to investigate the suitability of portable infrared spectrometers for phenotyping beef cattle aiming to genetically improving the quality of their meat.Meat quality traits(pH,color,water holding capacity,tenderness)were appraised on rib eye muscle samples of 1,327 Piemontese young bulls using traditional(i.e.,reference/gold standard)laboratory analyses;the same traits were also predicted from spectra acquired at the abattoir on the intact muscle surface of the same animals 1 d after slaughtering.Genetic parameters were estimated for both laboratory measures of meat quality traits and their spectra-based predictions.Results:The prediction performances of the calibration equations,assessed through external validation,were satisfactory for color traits(R^(2) from 0.52 to 0.80),low for pH and purge losses(R^(2) around 0.30),and very poor for cooking losses and tenderness(R^(2) below 0.20).Except for lightness and purge losses,the heritability estimates of most of the predicted traits were lower than those of the measured traits while the genetic correlations between measured and predicted traits were high(average value 0.81).Conclusions:Results showed that NIRS predictions of color traits,pH,and purge losses could be used as indicator traits for the indirect genetic selection of the reference quality phenotypes.Results for cooking losses were less effective,while the NIR predictions of tenderness were affected by a relatively high uncertainty of estimate.Overall,genetic selection of some meat quality traits,whose direct phenotyping is difficult,can benefit of the application of infrared spectrometers technology.

Genetic variability in ultrasound records of breast muscle in a broiler breeding program

Breast weight is one of the most economically important traits in the poultry industry, but direct selection for weight is expensive. The use of ultrasonography enables in vivo measurements of the broiler’s breast muscle size, which may be much more feasible for broiler selection. Previous studies of broilers concluded that ultrasound of the breast muscle is feasible and favorable for meat production. According to previously obtained genetic parameters, breast weight could be efficiently improved by ultrasound of the breast muscle. The use of ultrasonography for the indirect selection of breast weight does not affect the body composition or meat quality of broilers, despite the meat’s paleness and shear force;therefore, the use of ultrasound as a selection criterion might be a useful monitoring tool. Studies on the utilization of ultrasound in broiler breeding programs allow a better understanding of the relationship between traits of economic interest and the establishment of the selection schemes.

Optimization and Simulation of Plastic Injection Process using Genetic Algorithm and Moldflow

The use of plastic-based products is continuously increasing. The increasing demands for thinner products, lower production costs, yet higher product quality has triggered an increase in the number of research projects on plastic molding processes. An important branch of such research is focused on mold cooling system. Conventional cooling systems are most widely used because they are easy to make by using conventional machining processes. However, the non-uniform cooling processes are considered as one of their weaknesses. Apart from the conven- tional systems, there are also conformal cooling systems that are designed for faster and more uniform plastic mold cooling. In this study, the conformal cooling system is applied for the production of bowl-shaped product made of PP AZ564. Optimization is conducted to initiate machine setup parameters, namely, the melting temperature, injection pressure, holding pressure and holding time. The genetic algorithm method and Moldflow were used to optimize the injection process parameters at a minimum cycle time. It is found that, an optimum injection molding processes could be obtained by setting the parameters to the following values： TM=180℃; Pinj = 20MPa; Phold= 16MPa and thold=8s, with a cycle time of 14.11 s. Experiments using the conformal cooling system yielded an average cycle time of 14.19 s. The studied conformal cooling system yielded a volumetric shrinkage of 5.61% and the wall shear stress was found at 0.17 MPa. The difference between the cycle time obtained through simulations and experiments using the conformal cooling system was insignificant （below 1%）. Thus, combining process parameters optimization and simulations by using genetic algorithm method with Moldflow can be considered as valid.

Heritabilities and genetic and phenotypic correlations of litter uniformity and litter size in Large White sows

Litter uniformity, which is usually represented by within-litter weight coefficient of variation at birth （CVB）, could influence litter performance of sows and the profitability of pig enterprises. The objective of this study was to characterize CVB and its effect on other reproductive traits in Large White sows. Genetic parameters and genetic correlation of the reproductive traits, including CVB, within-litter weight coefficient of variation at three weeks （CVT）, total number born （TNB）, number born alive （NBA）, number born dead （NBD）, gestation length （GL）, piglet mortality at birth （Mo）, piglet mortality at three weeks （M3）, total litter weight at birth （TLW0）, and total litter weight at three weeks （TLW3） were estimated for 2 032 Large White litters. The effects of parity and classified litter size on CVB, CVT, TNB, NBA, NBD, GL, M0, M3, TLW0, and TLW3 were also estimated. The heritabilities of these reproductive traits ranged from 0.06 to 0.17, with the lowest heritability for CVB and the highest heritability for TLW0. Phenotypic and genetic correlations between these reproductive traits were low to highly positive and negative （ranging from -0.03 to 0.93, and -0.53 to 0.93, respectively）. The genetic correlations between TNB and CVB, and between M0 and CVB were 0.32 and 0.29, respectively. In addition, CVB was significantly influenced by parity and litter size class （P〈0.05）. All the results suggest that piglet uniformity should be maintained in pig production practices and pig breeding programs.

Phenotypic and genetic parameter estimation of juvenile growth and bottom color traits in half-smooth tongue sole,Cynoglossus semilaevis

Half-smooth tongue sole（Cynoglossus semilaevis） is a commercially important fish species. There were no reports about accurate genetic parameters of growth traits in C. semilaevis, despite efforts aimed at the culture of this species. Therefore, the main goal of this study was to estimate the parameters for the early growth traits（total length, body depth and body weight） of C. semilaevis based on the data obtained from 80 families. The trait of fish with pure white bottom or not（named as the trait of bottom color） was also analyzed. All the heritabilities estimated for the traits were medium, which varied from 0.210 to 0.362. Genetic correlations among growth traits were highly positive, varying from 0.913 to 0.959, indicating that selection of one of the three traits would result in correlated increase in the others. Also, genetic correlations between bottom color and growth traits were positive and varying from 0.241 to 0.353, suggesting that selection for the bottom color can be utilized to enhance the selection of growth traits. In addition, fish from the top performing 16 full-sib families were selected as broodstock, based on the above analysis and the comparison of family breeding value. This research provides an important basic material to implement selective breeding in C. semilaevis.

Genetic parameter estimation for juvenile growth and upper thermal tolerance in turbot(Scophthalmus maximus Linnaeus)

Twenty-six half-sib groups （53 full-sib families） of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring （40-50 individuals/family） and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mor-tality （range： 0.580%-1.391%） between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 （20.232% and 34.377%, respectively）. Mortality was highest on Day 16 （14.145%）. We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods （maximum log L）. Lastly, we estimated phenotypic and genetic correlation between the up-per thermal tolerance limit （UTT） and body weight （BW）. In this study, the positive phenotypic correlation was low between UTT and BW （0.093±0.029）. The genetic correlation between UTT and BW was negative （-0.044±0.239）. The heritability for upper thermal tolerance was low （0.087±0.032）, which is of approximate-ly moderate heritability. The heritability for body weight was high （0.303±0.074）. Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.