Genome-Wide Association Study Reveals Novel Genomic Regions for Grain Yield and Yield-Related Traits in Drought-Stressed Synthetic Hexaploid Wheat.

Madhav Bhatta,Vikas Belamkar,Alexey Morgounov,P Baenziger

doi:10.3390/ijms19103011

Abstract

Synthetic hexaploid wheat (SHW; 2n = 6x = 42, AABBDD, Triticum aestivum L.) is produced from an interspecific cross between durum wheat (2n = 4x = 28, AABB, T. turgidum L.) and goat grass (2n = 2x = 14, DD, Aegilops tauschii Coss.) and is reported to have significant novel alleles-controlling biotic and abiotic stresses resistance. A genome-wide association study (GWAS) was conducted to unravel these loci [marker–trait associations (MTAs)] using 35,648 genotyping-by-sequencing-derived single nucleotide polymorphisms in 123 SHWs. We identified 90 novel MTAs (45, 11, and 34 on the A, B, and D genomes, respectively) and haplotype blocks associated with grain yield and yield-related traits including root traits under drought stress. The phenotypic variance explained by the MTAs ranged from 1.1% to 32.3%. Most of the MTAs (120 out of 194) identified were found in genes, and of these 45 MTAs were in genes annotated as having a potential role in drought stress. This result provides further evidence for the reliability of MTAs identified. The large number of MTAs (53) identified especially on the D-genome demonstrate the potential of SHWs for elucidating the genetic architecture of complex traits and provide an opportunity for further improvement of wheat under rapidly changing climatic conditions.

Highlights

Drought is one of the most important abiotic stresses that reduce crop productivity and is expected to increase with the change in climate [1]
Winter wheat water requirements are higher from mid-March to mid-June, rainfalls were lower in both years compared to the 25-year mean rainfall
The present study showed Synthetic hexaploid wheat (SHW) have large amounts of genetic variation for grain yield (GY) and yield-related traits

Summary

Introduction

Drought is one of the most important abiotic stresses that reduce crop productivity and is expected to increase with the change in climate [1]. Erratic rainfall patterns caused by climate change may aggravate drought stress and will have a major impact on agriculture [2,3]. To cope with the challenges of drought stress, plant breeders have been focusing on improving drought tolerance since several decades [2,3,5]. Wheat is one of the most important staple cereal crops mainly grown under rainfed conditions [3,6] and is expected to suffer from drought stress [3]. Breeding for drought tolerance and identifying genomic regions and underlying candidate genes associated with drought tolerance are important for wheat improvement

Methods

Results

Conclusion