Genetic Analysis Of The Main Economical Traits Of Rainbow Trout (Oncorhynchus Mykiss)

Samples were obtained from Bohai Cold Water Fish Research Institute of Heilongjiang province,based on 4026 fish from 300 families in the 5 strains. The fish were recorded when they were 1year, 1.5 year and 2 year old. The study analyzed the major factors influencing the growth trait ofrainbow trout, compared different models and estimated variance components and geneticparameters of body weight, body length and condition factor utilizing Derivative-Free RestrictedMaximum Likelihood (DFREML) and animal model Best Linear Unbiased Prediction (BLUP). Thefixed effects, the permanent environment effects and the animal additive genetic effects werecalculated. Animals were ranked according to their EBV to provide information for selection. Thephenotypic and genetic trends of the growth traits by year were analyzed. The results showed asfollowing:Season, dam strain and sire strain significantly affected almost all growth traits. Year had no effecton condition factor, but had significant effect on other traits.Genetic parameters were estimated with single-trait, multiple-trait and repeatability animal models.Body weight and body length showed low to moderate heritability estimates ranging from 0.17 to0.45 by single-trait animal model, and condition factor were more heriTab, than size, which wereestimated about 0.47～0.65; Body weight, body length and condition factor exhibited moderate tohigh heritabilities by multiple-trait animal model, the heritabilities ranging between 0.32 two 0.60;Heritability was estimated with repeatability animal model for body weight, body length andcondition factor were 0.35,0.10,0.34, and the repeatability of growth trait was0.58,0.22 and 0.35respectively. Moreover, positive phenotypic and genetic correlations were found between bodyweight and body length and condition factor among 1-year-old fish, which were 0.923, 0.838,0.8794, 0.92, 0.9 and 0.917. The phenotypic correlation and genetic correlation between bodyweight and body length and condition factor of these 1.5-year-old fish are 0.55, 0.0646, -0.223,0.53, 0.51, -0.43 respectively, and 2-year-old fish phenotypic correlation and genetic correlation are0.31, -0.908, -1, 0.66, -0.026, -0.1337.After selecting different models, repeatability model was fit to estimate body weight and bodylength, accounting for additive effect and permanent environmental effect. Due to just consider theadditive effect, both single-trait and multiple-trait model were fitted to estimate condition factor.The ranks of all kinds of one-trait estimated breeding values were basely same to comprehensiveestimated breeding value. And all the genetic evaluation methods had significant correlations.