Application of multi-trait functional mapping of QTL in Populus euphratica Oliv. seedlings

Functional mapping frameworks can characterize quantitative trait loci (QTL) or nucleotides underlying complex dynamic traits. Functional mapping has been widely used in QTL mapping of a single trait or two traits, but research on multiple correlated traits remains relatively scarce. In this study, the structured antedependence (SAD) model was further derived and used to fit time-dependent covariance matrices for multiple traits. Four growth related traits of 340 Populus euphratica Oliv. F₁ populations as well as simulation experiments were used to test this multi-trait functional mapping model. In total, 173 significant loci were located on the chromosomes, except for 4, 9, 10, 15, and 16. Functional annotation identified 32 genes involved in early chloroplast development, lateral auxin transport, abiotic stress tolerance, and transmembrane transport system switching.