title: Quantitative trait loci × environment interactions for plant morphology vary over ontogeny in Brassica rapa.
abstract: Growth in plants occurs via the addition of repeating modules, suggesting that the genetic architecture of similar subunits may vary between earlier- and later-developing modules. These complex environment × ontogeny interactions are not well elucidated, as studies examining quantitative trait loci (QTLs) expression over ontogeny have not included multiple environments. Here, we characterized the genetic architecture of vegetative traits and onset of reproduction over ontogeny in recombinant inbred lines of Brassica rapa in the field and glasshouse. The magnitude of genetic variation in plasticity of seedling internodes was greater than in those produced later in ontogeny. We correspondingly detected that QTLs for seedling internode length were environment-specific, whereas later in ontogeny the majority of QTLs affected internode lengths in all treatments. The relationship between internode traits and onset of reproduction varied with environment and ontogenetic stage. This relationship was observed only in the glasshouse environment and was largely attributable to one environment-specific QTL. Our results provide the first evidence of a QTL × environment × ontogeny interaction, and provide QTL resolution for differences between early- and later-stage plasticity for stem elongation. These results also suggest potential constraints on morphological evolution in early vs later modules as a result of associations with reproductive timing.
authors.affiliation: Department of Biological Sciences, Central Washington University, Ellensburg, WA, 98926, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Dechaine
authors.affiliation: Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Brock
authors.affiliation: Agri-Aquaculture Nutritional Genomic Center, Genetic and Bioinformatics Unit, Instituto de Investigaciones Agropecuarias-Carillanca, Codigo Postal, 4780000, Temuco, Chile.
authors.forename: Federico L
authors.initials: FL
authors.lastname: Iniguez-Luy
authors.affiliation: Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Weinig
mesh_terms: D029741:Brassica rapa / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D004777:Environment; D017343:Genes, Plant; D007178:Inbreeding; D018547:Plant Stems / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic; D012098:Reproduction; D013997:Time Factors
keywords: Brassica rapa; QTL × environment interactions; evolutionary development; modularity; ontogeny; phenotypic plasticity; quantitative trait loci (QTLs); trade‐offs