Identification of Glu-D1 Alleles and Novel Marker–Trait Associations for Flour Quality and Grain Yield Traits under Heat-Stress Environments in Wheat Lines Derived from Diverse Accessions of Aegilops tauschii

Abstract

Heat stress during grain filling is considered one of the major abiotic factors influencing wheat grain yield and quality in arid and semi-arid regions. We studied the effect of heat stress on flour quality and grain yield at moderate and continuous heat stress under natural field conditions using 147 lines of wheat multiple synthetic derivatives (MSD) containing Aegilops tauschii introgressions. The study aimed to identify the marker–trait associations (MTAs) for the quality traits and grain yield under heat-stress conditions and identify stress-resilient germplasm-combining traits for good flour quality and grain yield. The MSD lines showed considerable genetic variation for quality traits and grain yield under heat-stress conditions; some lines performed better than the recurrent parent, Norin 61. We identified two MSD lines that consistently maintained relative performance (RP) values above 100% for grain yield and dough strength. We found the presence of three high-molecular-weight glutenin subunits (HMW-GSs) at the Glu-D1 locus derived from Ae. tauschii, which were associated with stable dough strength across the four environments used in this study. These HMW-GSs could be potentially useful in applications for future improvements of end-use quality traits targeting wheat under severe heat stress. A total of 19,155 high-quality SNP markers were used for the genome-wide association analysis and 251 MTAs were identified, most of them on the D genome, confirming the power of the MSD panel as a platform for mining and exploring the genes of Ae. tauschii. We identified the MTAs for dough strength under heat stress, which simultaneously control grain yield and relative performance for dough strength under heat-stress/optimum conditions. This study proved that Ae. tauschii is an inexhaustible resource for genetic mining, and the identified lines and pleiotropic MTAs reported in this study are considered a good resource for the development of resilient wheat cultivars that combine both good flour quality and grain yield under stress conditions using marker-assisted selection.

Novel Genetic Loci from Triticum timopheevii Associated with Gluten Content Revealed by GWAS in Wheat Breeding Lines

“…Near significant marker wsnp_Ex_c35886_43950102, the TraesCS1D02G159700 gene encoding the seed storage protein was located, which suggests that the locus may belong to Glu-D1. A similar locus containing the TraesCS1D02G159700 gene was discovered by Mohamed et al [58] when studying the wheat lines obtained from crosses with various accessions of Aegilops tauschii. In another research by Deng et al [54], two pleiotropic loci associated with GC and gluten index were identified using the DArT and SSR markers in chromosome 1D in marker interval Glu-D1-wPt3743.…”

Heat Stress Tolerant-QTL Identified Using Backcrossed Recombinant Inbred Lines Derived From Intra-specifically Diverse <em>Aegilops tauschii</em> Accessions

“…The results showed that a number of superior lines could be identified under various conditions and for different climate-resilient traits [15,16,18,24,25]. Moreover, GWAS analysis identified several MTAs under heat, drought, and heat-drought conditions [15,16,19,20,25]. Following the identification of several heat-tolerant lines from the MSD population, backcross inbred lines (BILs) were developed in the background of those heat-tolerant lines with exotic alleles from two Ae.…”

“…; abbreviated as WA). For more details on the characteristics of the experimental sites at DN and GRSF, refer to Elbashir et al [23] and Mohamed et al [19]. The Waha site is characterized as a semi-arid area with mostly haplusterts soil type, clay loam in texture, with pH range of 7.5-8.0, low N (0.05-0.20%), and low available P (30-60 kg ha -1 ) (http://susis.sd/south-region-0-30/, accessed on November 12, 2023).…”

“…All crop management including seed treatments, irrigation, fertilizer application, weed control, etc. followed the recommendations of the ARC for wheat production in Sudan as previously described [16,19,24]. During the winter season, there is usually no rainfall at any of the experimental sites.…”

“…The MSD population displayed significant genetic diversity when exposed to heat, drought, and heat-drought combination under field conditions in Sudan. Several MTAs were identified associated with heat, drought, heat-drought, and grain characteristics and quality [15][16][17][18][19][20].…”