Method of QTL Mapping in an F₂ Population using Phenotypic Means of F₃ Lines

抄録

Mapping of quantitative trait loci (QTLs) in plants was performed using the data of marker genotypes and phenotypic values of a quantitative trait in a segregating generation such as F₂ and BC1 derived from the crossing of two pure lines. A Iarge sample must be examined to map QTLs with small effects. However genotyping of many markers for a large number of individuals is costly. For mapping QTLs using a F₂ population, useful information is included in the derived F₃ Iines. Phenotypic measurements of F₃ Iines can be obtained at a relatively low cost. Therefore, by utilizing tlhe phenotypic measurements of F₃ in addition to F₂ data, the detection of QTLs could be improved even when only a small number of F₂ individuals are genotyped. In this paper a model for mapping QTLs is proposed, where the data of both F₂ mdividuals and F₃ Iines are jointly analyzed. The effectiveness of this method is evaluated theoretically and numerically and it is shown that the ability of detecting QTL can be remarkably enhanced, especially when the heritability of the trait is low.