title: Conditional QTL mapping of protein content in wheat with respect to grain yield and its components.
abstract: Grain protein content in wheat (Triticum aestivum L.) is generally considered a highly heritable character that is negatively correlated with grain yield and yield-related traits. Quantitative trait loci (QTL) for protein content was mapped using data on protein content and protein content conditioned on the putatively interrelated traits to evaluate possible genetic interrelationships between protein content and yield, as well as yield-related traits. Phenotypic data were evaluated in a recombinant inbred line population with 302 lines derived from a cross between the Chinese cultivar Weimai 8 and Luohan 2. Inclusive composite interval mapping using IciMapping 3.0 was employed for mapping unconditional and conditional QTL with additives. A strong genetic relationship was found between protein content and grain yield, and yield-related traits. Unconditional QTL mapping analysis detected seven additive QTL for protein content, with additive effects ranging in absolute size from 0.1898% to 0.3407% protein content, jointly accounting for 43.45% of the trait variance. Conditional QTL mapping analysis indicated two QTL independent from yield, which can be used in marker-assisted selection for increasing yield without affecting grain protein content. Three additional QTL with minor effects were identified in the conditional mapping. Of the three QTLs, two were identified when protein content was conditioned on yield, which had pleiotropic effects on those two traits. Conditional QTL mapping can be used to dissect the genetic interrelationship between two traits at the individual QTL level for closely correlated traits. Further, conditional QTL mapping can reveal additional QTL with minor effects that are undetectable in unconditional mapping.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Taian Subcenter of National Wheat Improvement Center, College of Agronomy, Shandong Agricultural University, Taian 271018, PR China. wanglinwang@126.com
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Fa
authors.initials: F
authors.lastname: Cui
authors.forename: Jinping
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Jun
authors.forename: Anming
authors.initials: A
authors.lastname: Ding
authors.forename: Chunhua
authors.initials: C
authors.lastname: Zhao
authors.forename: Xingfeng
authors.initials: X
authors.lastname: Li
authors.forename: Deshun
authors.initials: D
authors.lastname: Feng
authors.forename: Jurong
authors.initials: J
authors.lastname: Gao
authors.forename: Honggang
authors.initials: H
authors.lastname: Wang
mesh_terms: D002874:Chromosome Mapping / Q000379:methods*; D032461:Chromosomes, Plant / Q000235:genetics; D002523:Edible Grain / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D040641:Quantitative Trait Loci; D015203:Reproducibility of Results; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins