| Abstrakt: |
The additive genotypic variance, D, estimated with the F3of autogamous crops can be taken as an estimate of genotypic variance of its F∞-progeny. Two possible ways of estimating D are compared on the basis of their mean square error. For each of the two estimators the F3-population design, i.e., the number of lines, the number of plants per line and the number of parent plants, is chosen such that for a given experimental capacity its mean square error is minimal. Subsequently the two estimators are compared for various combinations of F∞-heritability, dominance level and experimental size. In by far the most cases the second estimator, D2, which takes twice the between F3-line genotypic variance as its estimate, outperforms the first estimator, D1, which uses both the between and the within F3-line genotypic variance. Further it is shown that, when it is necessary to work with plot totals because of low F∞-heritability, the performance of D1becomes very poor. With respect to the estimator of the dominance component of genotypic variance, H, its very large mean square error and its highly negative correlation with D1are demonstrated.Heredity (1989) 63, 73–81; doi:10.1038/hdy.1989.77 |
