Abstract: In the inheritance analysis of quantitative traits with relatively low heritability, the precision is relatively low. In this situation, an F_2:3 design, which is genotyped in F₂ plants and phenotyped in the F_2:3 progeny, is applied to increase the precision in the detection of quantitative trait loci (QTL). However, there are two issues needed to be further considered. One is to take full advantage of the mixture distribution for F_2:3 families of heterozygous F₂ plants, and the other to adopt multi-QTL genetic model. In this article, therefore, we extended our previous method from a single-QTL genetic analysis to joint analysis of all markers on the entire genome in the F_2:3 design. The proposed method here is on the basis of multi-QTL genetic model, and also takes full advantage of the mixture distribution mentioned above. Results of simulated studies showed that the new method provides accurate estimates for both the effects and the positions of QTL. Moreover, two strategies for sampling QTL effects were compared and the new one is better than the old one. In conclusion, the new method may is more suitable for mapping QTL for complex traits with low heritability.

Key words: Bayesian shrinkage estimation, Quantitative trait locus, multiple marker analysis, F_2:3 design