Genome-Wide Association Study identified novel candidate loci affecting wood formation in Norway spruce
Plant J. 2019, 100(1):83-100

Baison J, Vidalis A, Zhou L, Chen ZQ, Li Z, Sillanpää MJ, Bernhardsson C, Scofield D, Forsberg N, Grahn T, Olsson L, Karlsson B, Wu H, Ingvarsson PK, Lundqvist SO, Niittylä T, García-Gil MR

Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional Genome-Wide Association Study (GWAS) of 17 wood traits in Norway spruce using 178101 single-nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings.We applied a LASSO based association mapping method using a functional multi-locus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multi-locus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.

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