| In order to deeply understand the rainbow trout(Onchorynchus mykiss) main genetic regularity of growth traits, this study involving the Bohai, Denmark, Donaldson, Norway and California’s five rainbow trout strains as the research object, establish a complete diallel crossing experiment and get 25 composite materials. Hybrid offspring growth changes of body weight and body length were observed at 249, 397, 552 and 771 growth points. According to the the analysis of variance,multiple comparison, single factor analysis, multiple factor analysis, correlation analysis and statistical method for genetic analysisof body weight and body length in rainbow trout. Using the model of combining ability, establish the linear model between the phenotypic value of traits and genetic effect, based on the least square method through single trait genetic analysis and multiple traits genetic analysis to estimate effectvalues of linebred effects(LE), general combining ability(GCA), special combining ability(SCA), maternal effect(ME) and the reciprocal effects(RE) for body weight and body length at different growing point, the main results were as follows: 1. The significant analysis of body weight and body length between different hybrid combinations The single factor variance analysis of body weight and body length one by one, the results showed that 25 hybridized combinations have significant differences(P < 0.05) with body weight、body length significant differences(P < 0.05) at the different growing point. Multiple comparison confirmed that between 20 hybrid combinations and five corresponding self-breeding have significant differences(P < 0.05).249 ~ 771 days of age comprehensively, the average weight of Donaldson hybrid combinations with Bohaireach maximum values 229.09 g and 1737.62 g at 397, 771 days of age, compared with corresponding self-breeding, the significant were extremely difference(P < 0.01) at 249 days of age. Donaldson hybrid combinations with Bohai of length trait reach maximum average 26.50 cm, 38.58 cm and 50.60 cm at 397, 552 and 397 days of age. Compared with self-breeding group of Donaldson, have extremely different significant at four growing points(P < 0.01). 2. The phenotypic correlation analysis of between body weight and body length traits at different growth pointsPhenotypic correlation analysis results show that body length and weight growth traits is not independent of each other at different growing points, and there is a certain relationship, and the correlation coefficients were showing extremely significant positive correlation between body weight and body length traits at the same growth point r = 0.67 ~ 0.82, P < 0.01. The correlation coefficients is highly related to the correlation coefficient when the 249 th day r = 0.82, P < 0.01. At the 397, 552 and 771 days of age, The correlation coefficients respectively are moderate positive correlation at 397, 552 and 771 days of age r = 0.67, 0.79 and 0.79, P < 0.01. 3. Genetic analysis of a single traitUsing the method of least squares estimategenetic parameters of single variablefor body weight and body length in rainbow troutat different growth points. The results showed that only a small amount of genetic effect is significant at different growing points, the genetic effect performance is not the same among the different traits and growing points.Weight traits, the LE of Donaldson have negative effects at four growing points, the range of 10.21 ~ 165.83, the effect is significant(P < 0.05).The GCA of Bohai have the maximum value 17.82 at 552 age of days, followed by the GCA of Donaldson when 397 days of age, and the effect is significant at 249, 397 days of age. The ME of Denmark has bigger at four growing points, range of 17.96 ~ 10.14, Genetic analysisin the 249 days of age, the effect is significant. The ME of different strains showed a trend of weakening along with the age growth. The SCA reached the maximum values of 62.66, 18.22 bythe hybrid combinations of Donaldson with Bohai and Donaldson with Norwayat 771 days of age. The RE of Hybrid combination has the maximum of 238.58 and the minimum value is-366.93, the effect is significant.Length traits, the LE of Donaldson have negative effects at four growing points, the range of 0.73 ~ 2.06, the effect is all significant. The GCA of Bohai have the maximum values 0.26 at 552 age of days, followed by GCA of Denmark when 397 days of age. The ME of Donaldson reach maximum of 0.91, 1.48 at 249, 397 days of age, effect is significant. The SCA ofthe hybrid combinations of Donaldson with Bohai and Donaldson with Norway were positive at four growing points, largest range of 0.03 ~ 0.03, the effects were significant at 771 days of age. The RE of Hybrid combination has the maximum value 4.74 and the minimum value is-5.99, and the effect is significant. 4. Genetic analysis of multi-traitsUsing the method of least squares estimategenetic parameters of multivariable for body weight and body length in rainbow troutat different growth points. The results showed that only a small amount of genetic effect is significant at different growing points, the genetic effect performance is also not the same among the different traits and growing points.Weight traits, the LE of Donaldson have negative effects at four growing points, the range of 11.10 ~ 161.22, the effect is significant(P < 0.05).The GCA of Donaldson have the maximum values 12.16 at 249 days of age,followed by the maximum 32.69 of Bohai at 552 days of age, and the effect is significant. The ME of Donaldson early have a maximum value of 21.62 at 397 days of age, and the effect is significant.The SCA reached the maximum values of 47.65, 11.45 by the hybrid combinations of Donaldson with Bohai and Donaldson with Norway at 771 days of age.The RE of Hybrid combination have the maximum value 202.44 and the minimum value is-370.71, and the effect is significant.Length traits, the LE of Donaldson have negative effects at four growing points, the range of 0.76 ~ 2.26, and the differences are significant. The GCA of Bohai have the maximum values 0.42 at 552 age of days, followed by GCA of Donaldson when 397 days of age. The ME of Donaldson reach maximum values of 1.04, 1.59 at 249, 397 days of age, and the effect is significant. The SCA ofthe hybrid combinations of Donaldson with Bohai and Donaldson with Norway were positive at four growing points, range of 0.12 ~ 0.12,the effect were significant at 771 days of age.The RE of Hybrid combination have the maximum of 5.16 and the minimum value is-6.49, and the effect is significant.The comprehensive analysis results show that the genetic analysis have difference between the univariate and multivariate analysis, significance and the size of effect value have change.between different combinations have significant differences in 25 hybrid combinations, select the parent is valid. From the point of GCA, the strains of Bohai and Donaldson suitable for good parents, help to improve growth performance; From the point of SCA, during the whole observation the hybrid combinations of Donaldson with Bohai and Donaldson with Norway as the best combination, the hybrid effect is best. |
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