Associations between genomic ancestry, genome size and capitula morphology in the invasive meadow knapweed hybrid complex (Centaurea × moncktonii) in eastern North America

摘要: Plant invasions are prime opportunities for studying hybridization and the nature of species boundaries, but hybrids also complicate taxonomic treatment management introduced taxa. In this study, we use population genomics to estimate extent genomic admixture test its association with morphology genome size in a hybrid complex knapweeds invasive North America: meadow knapweed (Centaurea × moncktonii) parental (C. jacea C. nigra). We sampled 20 populations from New York Vermont, USA, used genotyping by sequencing identify single nucleotide polymorphisms order genome-wide ancestry classify individuals into genotype classes. then tested between degree introgression variation subset traits diagnostic taxa, namely capitula monoploid size. Genomic clustering revealed two clearly defined lineages, as well many admixed forming continuous gradation introgression. Individual assignments classes advanced generation intercrosses backcrosses, suggesting has been extensive unimpeded strong reproductive barriers Variation unadmixed, presumed parental, lineages exhibited continuous, some cases transgressive, segregation among introgressed hybrids. Genome was divergent although had smaller genomes relative additive expectations. Our study demonstrates deep porous complex. addition associations ancestry, morphology, expressed more extreme phenotypic values size, indicating transgressive segregation, bias towards genomes, possibly due downsizing. Future studies will apply these results experimentally how introgression, reduction interact confer invasiveness.