Estimation of genetic parameters for growth and upper thermal tolerance traits in turbot Scophthalmus maximus

Genetic parameters of growth and upper thermal tolerance traits of turbot Scophthalmus maximus were analyzed based on the data collected during experiments with 753 individuals from 40 families of turbot that were exposed to a thermal tolerance challenge,and two animal models were established by including a common full-sib effect or inverse.The variance components in each model were estimated with the average information restricted maximum likelihood method using WOMBAT software,and the differences between the two models were tested by likelihood ratio test.The results showed that better estimation was achieved with model Ⅰ for estimating genetic parameters of body weight and upper thermal tolerance,whose heritability was(0.22?0.09)and(0.026?0.034),respectively.The differences between genetic parameters of relative fatness by the two animal models were not significant,and the range of heritability was (0.21?0.18)-(0.39?0.11).The correlation analysis showed that the phenotypic correlation coefficients between body weight and relative fatness,body weight and upper thermal tolerance were 0.13 and 0.04,respectively,while the phenotypic correlation coefficient between relative fatness and upper thermal tolerance was 0.13.The genetic correlation coefficients between body weight and relative fatness,body weight and upper thermal tolerance were 0.01 and -1.00,respectively.The genetic correlation coefficient between relative fatness and upper thermal tolerance was 0.05.The results indicated that model Ⅰ without including a common full-sib effect was better than model Ⅱ to be used to estimate the genetic parameters in this study.