Identification of Main-Effect and Environmental Interaction QTL and Their Candidate Genes for Drought Tolerance in a Wheat RIL Population Between Two Elite Spring Cultivars

Abstract

Understanding the genetics of drought tolerance can expedite the development of drought-tolerant cultivars in wheat. In this study, we dissected the genetics of drought tolerance in spring wheat using a recombinant inbred line (RIL) population derived from a cross between a drought-tolerant cultivar, ‘Reeder’ (PI613586), and a high-yielding but drought-susceptible cultivar, ‘Albany.’ The RIL population was evaluated for grain yield (YLD), grain volume weight (GVW), thousand kernel weight (TKW), plant height (PH), and days to heading (DH) at nine different environments. The Infinium 90 k-based high-density genetic map was generated using 10,657 polymorphic SNP markers representing 2,057 unique loci. Quantitative trait loci (QTL) analysis detected a total of 11 consistent QTL for drought tolerance-related traits. Of these, six QTL were exclusively identified in drought-prone environments, and five were constitutive QTL (identified under both drought and normal conditions). One major QTL on chromosome 7B was identified exclusively under drought environments and explained 13.6% of the phenotypic variation (PV) for YLD. Two other major QTL were detected, one each on chromosomes 7B and 2B under drought-prone environments, and explained 14.86 and 13.94% of phenotypic variation for GVW and YLD, respectively. One novel QTL for drought tolerance was identified on chromosome 2D. In silico expression analysis of candidate genes underlaying the exclusive QTLs associated with drought stress identified the enrichment of ribosomal and chloroplast photosynthesis-associated proteins showing the most expression variability, thus possibly contributing to stress response by modulating the glycosyltransferase (TraesCS6A01G116400) and hexosyltransferase (TraesCS7B01G013300) unique genes present in QTL 21 and 24, respectively. While both parents contributed favorable alleles to these QTL, unexpectedly, the high-yielding and less drought-tolerant parent contributed desirable alleles for drought tolerance at four out of six loci. Regardless of the origin, all QTL with significant drought tolerance could assist significantly in the development of drought-tolerant wheat cultivars, using genomics-assisted breeding approaches.

Multi-Locus GWAS for Grain Weight-Related Traits Under Rain-Fed Conditions in Common Wheat (Triticum aestivum L.)

“…(iv) SNP for GFD on 7A (145.43 cM) co-localized with a marker (wsnp_CAP7_c1321_664478~IACX7848) associated with DTA and GY (Qaseem et al, 2018 ). (v) SNP for GWPE on 6B, co-localized with MTAs/QTL for thousand grain weight (TGW) and grain yield, identified in three earlier studies (Mathews et al, 2008 ; Ahmed et al, 2020 ; Rabbi et al, 2021 ). The markers identified in these three earlier studies include a SSR marker gwm132 on 6B (67.10 cM) associated with GY under DS (Mathews et al, 2008 ).…”

“…We assume that the remaining 25 MTAs are novel. The five co-localized MTAs listed in Table 5 , include the following: (i) SNP for DTA on 4B co-localized with a QTL for DTH and GY ( QDH.ndsu.4B ; Rabbi et al, 2021 ). (ii) SNP for DTA on 2B co-localized with a SNP for DTH (Gahlaut et al, 2019 ).…”

“…The markers identified in these three earlier studies include a SSR marker gwm132 on 6B (67.10 cM) associated with GY under DS (Mathews et al, 2008 ). The other two co-localized genomic region at 64.82 cM ( QTKW.ndsu.6B ) and at 67.24 cM (BS00063801_51) were associated with TGW under DS (Ahmed et al, 2020 ; Rabbi et al, 2021 ). These QTLs/MTAs can be utilized for MAS with higher level of confidence.…”

Proteomic analysis of near‐isogenic lines reveals key biomarkers on wheat chromosome 4B conferring drought tolerance

“…A large number of quantitative trait loci (QTLs) have been reported in wheat for grain yield and yield components under water stress through QTL interval mapping and genome‐wide association studies (Czyczyło‐Mysza et al., 2011; Fleury et al., 2010; Gupta et al., 2017; Xu et al., 2017; Yang et al., 2007). However, only some of the QTLs had major effects (explaining ≥20% of the phenotypic variation) and stability (detected in several environments), whereas most were unstable and had only a small effect (Bennett et al., 2012; Gahlaut et al., 2017; Rabbi et al., 2021). In a 2‐year study, a consistent major genomic region qDSI.4B.1 for yield and yield components under drought stress was reported on the short arm of chromosome 4B (4BS) with a positive allele from wheat cultivar C306 (RGN/CSK3//2*C591/3/C217/N14//C281).…”

Investigating the Genetic Contribution of Effective Traits in Grain Yield of Durum Wheat under the Normal Irrigation and Drought Stress Conditions at the Terminal Drought

“…The occurrence of stress during reproductive growth signi cantly reduces wheat grain yield (Abid et Focusing on applying new strategies to face undesirable conditions and managing research and development to introduce cultivars tolerant to drought are the approaches suggested to decrease the impact of climate changes (Javadi et al 2023). Improvement of cultivars tolerant to drought is one of the most important goals for plant breeders which increases the tolerance possibility of understanding the genetic and molecular basis of drought; it is the key to decrease yield loss due to drought stress (Rabbi et al 2021). New wheat and barley genotypes with high degrees of drought tolerance are produced through breeding by crossing promising drought resistant genotypes and selecting their progenies (Sallam et al 2019).…”