The long-term objective of FIBRAGEN is to expand markets for flax bioproducts by developing optimized feedstocks for use in advanced composite materials. Both fiber flax and linseed already produce some of the longest and strongest fibers of any crop, and these fibers can be used to replace synthetic materials such as glass as reinforcements in composites. Compared to traditional composites, natural fiber reinforced biomaterials are expected to have lower density, lower cost, and a lower environmental impact that traditional composites. Establishment of a robust industry in biocomposites requires a reliable supply of high-quality flax feedstocks. Feedstock development relies on the availability of molecular markers linked to traits of interest. Such markers are completely lacking for fiber traits in flax. The most important traits for fiber feedstocks are yield, high tensile strength and the ability to form a strong interface with polymers in a composite. The novel molecular markers that will be developed by FIBRAGEN can be used in either linseed varieties (for dual purposed flax in Canada) or in fiber flax (for composite-dedicated crops in Europe). We will build on our recently completed whole-genome assembly of flax to identify SNP markers that we will be map to quantitative traits (QTL) for fiber yield, quality and disease resistance in existing recombinant inbred (RIL) populations. SNPs will be identified by sequencing of reduced-representation libraries of a large and diverse (67 accession) panel of fiber flax and linseed accessions. In parallel, breeders from four FIBRAGEN partner companies in France and Canada will provide other FIBRAGEN team members with samples of field-grown straw from a large panel of diverse genotypes to evaluate the range of existing fiber qualities. Selected varieties will be field-grown in multiple locations in northern Europe and in Canada, and subsets will be analyzed according to their anatomy, genotype, biochemical composition, micromechanical qualities, gene and protein expression and performance in small-scale composite production. Larger quantities of a limited set of germplasm accessions will be evaluated using pultrusion manufacturing methods in a composite manufacturing pilot plant. All of these data will be integrated to identify correlations between genetic polymorphisms, gene expression, fiber composition, and fiber performance in commercial applications. The major deliverables at the end of the project are a set of mapped SNPs, which can be used in marker-assisted selection of yield and quality, as well as a better understanding of the optimal properties of feedstocks for high performance natural composites. Together, these activities will also advance scientific understanding of cell wall development in cellulose-rich fibers, and the diversity of flax genetic resources.