Multi-Trait Multi-Model QTL Mapping Strategies in Flax

Quantitative trait locus (QTL) mapping is a powerful genomics-based statistical genetics method to study the inheritance of complex quantitative traits by providing statistical inference of single quantitative trait nucleotides (QTNs) or genomic regions associated with traits of interest and for the prediction of their candidate genes. Two major strategies - genome-wide association study (GWAS) based on diverse genetic panels and QTL mapping based on biparental populations - are widely used in plants including flax. New statistical models are constantly being developed to improve detection accuracy, power and computing performance. The use of multiple statistical models increases the chances of detection and provide some indication of reliability through the detection by multiple models. In the last decade, QTL mapping strategies have been applied to study the inheritance of many quantitative traits in flax, including seed yield and agronomic traits, fibre yield and quality, seed oil components, and abiotic and biotic stress-related traits. More than 1000 QTNs/QTLs were identified for more than 37 traits in flax. Significant additive effects were observed for most of these QTLs/QTNs. Candidate genes neighboring some large-effect QTLs/QTNs were predicted for many of them. These results provide potential to pyramid the favorable alleles of multiple traits into new cultivars or pre-breeding germplasm in flax breeding.