Linkage disequilibrium and genome-wide association mapping in tetraploid wheat (Triticum turgidum L.)

PLoS One. 2014 Apr 23;9(4):e95211. doi: 10.1371/journal.pone.0095211. eCollection 2014.

Abstract

Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker-trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker-trait associations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Genome, Plant / genetics
  • Genome-Wide Association Study
  • Linkage Disequilibrium / genetics*
  • Quantitative Trait Loci / genetics
  • Tetraploidy*
  • Triticum

Grants and funding

This work has been funded by the research project Mappa 5A, Esplora, Biomassval from the Ministry of Agricultural, Food and Forestry Policies (Italy). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.