title: Unraveling epistasis with triple testcross progenies of near-isogenic lines.
abstract: Libraries of near-isogenic lines (NILs) are a powerful plant genetic resource to map quantitative trait loci (QTL). Nevertheless, QTL mapping with NILs is mostly restricted to genetic main effects. Here we propose a two-step procedure to map additive-by-additive digenic epistasis with NILs. In the first step, a generation means analysis of parents, their F(1) hybrid, and one-segment NILs and their triple testcross (TTC) progenies is used to identify in a one-dimensional scan loci exhibiting QTL-by-background interactions. In a second step, one-segment NILs with significant additive-by-additive background interactions are used to produce particular two-segment NILs to test for digenic epistatic interactions between these segments. We evaluated our approach by analyzing a random subset of a genomewide Arabidopsis thaliana NIL library for growth-related traits. The results of our experimental study illustrated the potential of the presented two-step procedure to map additive-by-additive digenic epistasis with NILs. Furthermore, our findings suggested that additive main effects as well as additive-by-additive digenic epistasis strongly influence the genetic architecture underlying growth-related traits of A. thaliana.
authors.affiliation: Institute of Plant Breeding, Technical University of Munich, 85350 Freising, Germany.
authors.forename: Jochen C
authors.initials: JC
authors.lastname: Reif
authors.forename: Barbara
authors.initials: B
authors.lastname: Kusterer
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Piepho
authors.forename: Rhonda C
authors.initials: RC
authors.lastname: Meyer
authors.forename: Thomas
authors.initials: T
authors.lastname: Altmann
authors.forename: Chris C
authors.initials: CC
authors.lastname: Schön
authors.forename: Albrecht E
authors.initials: AE
authors.lastname: Melchinger
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D018533:Biomass; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D004843:Epistasis, Genetic; D005799:Genes, Dominant; D014644:Genetic Variation; D005838:Genotype; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology; D040641:Quantitative Trait Loci / Q000235:genetics; D019655:Quantitative Trait, Heritable