Genome Wide Association Study (GWAS) of Yield-Related Traits in Flax

Flax (Linum usitatissimum L.) has become an important multi-purpose crop due to an increasing demand for both functional ingredients and natural fibres. Nonetheless, until recently, flax genetic improvement had been based on conventional breeding techniques due to the limited genomic tools for flax genetic applications. Advances in next generation sequencing (NGS) technologies and the assembly of suitable germplasm collections enable the genome-wide dissection of complex traits, providing the bases for flax improvement through marker-assisted breeding. In order to conduct genome wide association studies (GWAS) for yield (YLD), seeds per boll (SPB) and 1000-seed weight (TSW), the Canadian flax core collection was assessed across six environments and genotyped with 1.7 million single nucleotide polymorphisms (SNPs). GWAS identified fifty one SNPs associated with yield-related traits at least in one environment. Based on the LD between SNPs, two quantitative trait loci (QTL) for YLD were proposed on linkage groups 5 and 9. Moreover, GWAS mapped six and fourteen QTL for SBP and TSW, respectively. One QTL was common to YLD and SPB on linkage group 9. This work will contribute to a more efficient flax cultivar development, but also illustrates the complex genetic architecture of YLD and its potential indirect breeding through yield components.