Genome-wide association analysis of agronomic traits in wheat under drought-stressed and non-stressed conditions

PLoS One. 2017 Feb 24;12(2):e0171692. doi: 10.1371/journal.pone.0171692. eCollection 2017.

Abstract

This study determined the population structure and genome-wide marker-trait association of agronomic traits of wheat for drought-tolerance breeding. Ninety-three diverse bread wheat genotypes were genotyped using the Diversity Arrays Technology sequencing (DArTseq) protocol. The number of days-to-heading (DTH), number of days-to-maturity (DTM), plant height (PHT), spike length (SPL), number of kernels per spike (KPS), thousand kernel weight (TKW) and grain yield (GYLD), assessed under drought-stressed and non-stressed conditions, were considered for the study. Population structure analysis and genome-wide association mapping were undertaken based on 16,383 silico DArTs loci with < 10% missing data. The population evaluated was grouped into nine distinct genetic structures. Inter-chromosomal linkage disequilibrium showed the existence of linkage decay as physical distance increased. A total of 62 significant (P < 0.001) marker-trait associations (MTAs) were detected explaining more than 20% of the phenotypic variation observed under both drought-stressed and non-stressed conditions. Significant (P < 0.001) MTA event(s) were observed for DTH, PHT, SPL, SPS, and KPS; under both stressed and non-stressed conditions, while additional significant (P < 0.05) associations were observed for TKW, DTM and GYLD under non-stressed condition. The MTAs reported in this population could be useful to initiate marker-assisted selection (MAS) and targeted trait introgression of wheat under drought-stressed and non-stressed conditions, and for fine mapping and cloning of the underlying genes and QTL.

MeSH terms

  • Adaptation, Physiological / genetics*
  • Chromosome Mapping
  • Droughts
  • Genome, Plant*
  • Genome-Wide Association Study
  • Genotype
  • Linkage Disequilibrium
  • Phenotype
  • Plant Breeding
  • Quantitative Trait Loci*
  • Quantitative Trait, Heritable*
  • Stress, Physiological / genetics*
  • Triticum / genetics*

Grants and funding

National Research Foundation of South Africa is sincerely thanked for financial support of the study.