[Study on the estimation methods of genetic parameters with mixed family]

By theoretically supposing the male variance component be equal to the female variance component, a new method and an approximate estimation method of heritability are suggested on the basis of decomposing the expected mean squares in variance analysis with mixed families. Seven estimation methods of heritability are compared by an actual estimation example. The results indicate that the difference of the estimation value between full-sib analysis method and the method suggested in this paper is the smallest and the standard error of estimated heritability by the latter method is the smallest among the standard error of estimated heritability by the latter method is the smallest among the seven methods. Also the approximate method is effective. For all methods, the more disequilibrium of the data, the bigger difference of the estimate value by those methods. The new method can be used when the difference of variance components between male and female is relatively large with full-sib analysis in actual estimation. Moreover, the new method is easily calculated because the two-way classification data was analyzed by one-way classification variance analysis and the average relationship coefficient among mixed families may not need to be calculated.