2.3 SNP genotyping and genetic map construction
SNP loci were selected from whole genome resequencing data generated for the parent trees of the pedigree, focusing on loci that were fixed for different alleles in P. deltoides and P. trichocarpa . This yielded loci that were maternally informative for the SNP derived fromP. trichocarpa . These were incorporated into an Illumina Infinium Bead Array which was used to genotype 3,568 SNP loci in 692 of the progeny. This data was then used to create the genetic map which was composed of 19 linkage groups corresponding to 19 Populuschromosomes. Genotyping and map construction are described in more detail elsewhere (Muchero et al., 2015).