| Heterosis could be utilized effectively only in a few traits such as growth, reproduction under the domestic crossing production system nowdays. Adaptable untilization about mutipltraits is scarely. On one hand, the consciousness of utilization of mutipltraits heterosis is not enough. On the other hand, the devotion of research in heterosis machenisms is not enough, and the knowledge of the appearance of mutiptraits in pig is scarce, which makes the producer cann't utilize the heterosis properly in the commercial production. Three kinds of parental pig (Tongcheng, Landrace and Large White) and two crossbred pigs [Landracex (Yorkshirex Tongcheng) (LxYxT), Yorkshirex (LandracexTongcheng) (YxLxT)], which in total number was 162, were used as experimental materials. The purpose of the study is aimed at the part which not been studied on in pig to analyze heterosis base on the systematical test of 24 traits related growth, carcass and meat quality. The emphases are analyses of the relationships of mutipltraits heterosis in the pig, in which some works were done to explore the mechanisms of relationship between different traits from different angle of view to advance the academic sustain of adaptablely utilization of the aggregate heterosis. It is the result:1 Thorough analysis was done about traits in the growth, carcass and meat quality in different breeds and cross combinations. It shows that the growth traits in crossbred are higher than the parental breeds, and most carcass traits are closed or a little lower than the highest parental breed. Two crossbred combinations are synchronously ideal in the meat quality traits, parts of which have significant difference in stastistics.2 A new statistical formula is constructed for testing the significant level of estimated results of classic estimation of three-way heterosis. Base on the large sample theory, the formula directly aiming at the sampling error is deduced, which is derived to test the estimtated formula. To contrast with the methods already existed, the formula cannot be distorted in the statistics information and in test power, and more validations are needed to prove the result in practice.3 The result for assessing the integrated heterosis in two crossing combination is achieved by using the formula of principal component analysis, which works in a transferring form by removing correlation between traits. The score of LYT with four principal components is 1488.286, and 1481.736 is as of YLT. The result indicates that theintegrated heterosis of LYT is larger and LYT is a more ideal crossing combination.4 The conception of combination heritability and the unbiased estimated method are put forward in this study. The result indicates most combination heritabilities are close to narrow sense heritability, but it has a higher value in backfat, percentage of ham and muscle drip loss, and has a little lower value in meat color score. It is probably caused by the smallness of sample size and the distorted distribution of data itself and it is nothing to do with the statistics methods.5 The cluster analysis is made by the estimated individual heterosis ratio in all traits, and the intuitionistic result of the relationship of them is obtained. It indicates that the relationships of individual heterosis ratio are according to the paternal merits in most traits, but nine of important economic traits are different with cluster.6 Hypothesis of genome potential energy releasing in heterosis is established and mathematical model base on the hypothesis and the energy parameters come into first emergence in the present study.7 Expressive mechanism of relationships of heterosis between different traits are explored in the study. The idea of graph theory, combination heritability and potential energy based on hypothesis of genome potential energy releasing are used to explore expressive mechanism of relationships of heterosis, which includes the relationships of parental traits, genetic parameters and energy parameters. The results indicate that the direction and...
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