Genetic diversity and linkage disequilibrium using SNP (KASP) and AFLP markers in a worldwide durum wheat (Triticum turgidum L. var durum) collection

PLoS One. 2019 Jun 28;14(6):e0218562. doi: 10.1371/journal.pone.0218562. eCollection 2019.

Abstract

The aim of this work was to analyze the genetic diversity and linkage disequilibrium in a collection of 168 durum wheat accessions (Triticum turgidum L. var. durum) of different origins. Our collection was mainly composed of released and unreleased Argentinian germplasm, with additional genotypes from Italy, Chile, France, CIMMYT, Cyprus, USA and WANA region. To this end, the entire collection was characterized with 85 Single Nucleotide Polymorphism (SNP) markers obtained by Kompetitive Allele Specific PCR (KASP), giving a heterozygosity (He) mean value of 0.183 and a coefficient of genetic differentiation (Gst) value of 0.139. A subset of 119 accessions was characterized with six Amplified Fragment Length Polymorphism (AFLP) primer combinations. A total of 181 polymorphic markers (125 AFLP and 56 SNP) amplified across this subset revealed He measures of 0.352 and 0.182, respectively. Of these, 134 were selected to estimate the genome-wide linkage disequilibrium obtaining low significant values (r2 = 0.11) in the subset, indicating its suitability for future genome-wide association studies (GWAS). The structure analysis conducted in the entire collection with SNP detected two subpopulations. However, the structure analysis conducted with AFLP markers in the subset of 119 accessions proved to have greater degree of resolution and detect six subpopulations. The information provided by both marker types was complementary and showed a strong association between old Argentinian and Italian germplasm and a contribution of CIMMYT germplasm to modern Argentinian, Chilean and Cypriot accessions. The influence of Mediterranean germplasm, mainly from Italy, on part of the modern Argentinian cultivars or breeding lines was also clearly evidenced. Although our analysis yields conclusive results and useful information for association mapping studies, further analyses are needed to refine the number of subpopulations present in the germplasm collection analyzed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amplified Fragment Length Polymorphism Analysis
  • Gene Frequency
  • Genetic Markers
  • Genetic Variation*
  • Genetics, Population
  • Genotype
  • Linkage Disequilibrium*
  • Phylogeny
  • Polymerase Chain Reaction
  • Polymorphism, Single Nucleotide*
  • Triticum / classification*
  • Triticum / genetics*

Substances

  • Genetic Markers

Grants and funding

Funded by VCE. ANPCYT (PICT 2012 – 0660, PICT 2015 – 1401). AGENCIA NACIONAL DE PROMOCIÓN CIENTÍFICA Y TECNOLÓGICA. http://www.agencia.mincyt.gob.ar/index.php. VCE. NUTRIPASTA PCESU9-UNS993. Universidad Nacional del Sur/MINISTERIO DE EDUCACION. https://www.argentina.gob.ar/educacion/universidades/programa-de-cooperativismo. VCE. MSCA-RISE-2015 project ExpoSEED (grant no. 691109). EUROPEAN COMMISION. https://ec.europa.eu/info/funding-tenders/opportunities/portal/screen/home. SD. International Maize and Wheat Improvement Center. https://www.cimmyt.org/es/. VCE PFR. CONICET, CERZOS – CCT CONICET Bahía Blanca. https://www.cerzos-conicet.gob.ar/. PFR. R630/12. UNIVERSIDAD NACIONAL. DEL SUR. https://www.uns.edu.ar/contenidos/40/482#pasantias-en-centros-de-investigacion. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.