Identification of Quantitative Trait Loci Relating to Flowering Time, Flag Leaf and Awn Characteristics in a Novel Triticum dicoccum Mapping Population

Abstract

<jats:p>Tetraploid landraces of wheat harbour genetic diversity that could be introgressed into modern bread wheat with the aid of marker-assisted selection to address the genetic diversity bottleneck in the breeding genepool. A novel bi-parental Triticum turgidum ssp. dicoccum Schrank mapping population was created from a cross between two landrace accessions differing for multiple physiological traits. The population was phenotyped for traits hypothesised to be proxies for characteristics associated with improved photosynthesis or drought tolerance, including flowering time, awn length, flag leaf length and width, and stomatal and trichome density. The mapping individuals and parents were genotyped with the 35K Wheat Breeders’ single nucleotide polymorphism (SNP) array. A genetic linkage map was constructed from 104 F4 individuals, consisting of 2066 SNPs with a total length of 3295 cM and an average spacing of 1.6 cM. Using the population, 10 quantitative trait loci (QTLs) for five traits were identified in two years of trials. Three consistent QTLs were identified over both trials for awn length, flowering time and flag leaf width, on chromosomes 4A, 7B and 5B, respectively. The awn length and flowering time QTLs correspond with the major loci Hd and Vrn-B3, respectively. The identified marker-trait associations could be developed for marker-assisted selection, to aid the introgression of diversity from a tetraploid source into modern wheat for potential physiological trait improvement.</jats:p>

Progenitor species hold untapped diversity for potential climate-responsive traits for use in wheat breeding and crop improvement

“…This QTL was found to be a cis-element GATA box in Vrn-A3 (located on chromosome 7AS), which suppressed the late-flowering (photoperiod sensitive) Ppd-A1b allele (Nishimura et al 2018 ). A QTL controlling flowering time was also reported on 7B linked to Vrn-B3 in an emmer mapping population (Wright et al 2020 ). Takenaka and Kawahara ( 2012 ) identified novel loss of function alleles in tetraploid Ppd-A1 in emmer wheat that do not confer PI but may induce small variations in flowering time.…”

“…Diversity in flowering time has been further characterised by several studies in tetraploids wheats (Nishimura et al 2018 ; Wright et al 2020 ; Würschum et al 2019 ). Alleles of the Ppd-A1 associated with early flowering (but distinct from the Ppd-A1a alleles described by Wilhelm et al 2009 ) were detected in emmer wheat by Nishimura et al ( 2018 ) who also identified an early heading date QTL associated with Vrn-A3 .…”

“…The wheat-relative array has been used to aid the introgression of the diploid wheat-relative Ambylopyrum muticum into a hexaploid wheat background through MAS (King et al 2017 ). Furthermore, the Wheat Breeders’ array has been used in several studies for identifying QTLs in tetraploid wheat (Lucas et al 2017 ; Wright et al 2020 ). Low-cost genotyping platforms designed to demonstrate potential genetic variability between progenitor species and elite varieties are a tool of growing importance in exploring and harnessing diversity and have been deployed in many crops such as barley (Bayer et al 2017 ), rice (Chen et al 2013 ) and maize (Xu et al 2017 ).…”

Mapping and validation of major and stable QTL for flag leaf size from tetraploid wheat

“…Wright et al. (2020) created a novel biparental population using two tetraploid landrace accessions differing for multiple physiological traits and identified one QTL for FLW on chromosome 5B based on a 35K wheat SNP array.…”

High‐temperature stress in crops: male sterility, yield loss and potential remedy approaches

“…For example, the Aegilops speltoids, a close relative of hexaploid wheat (bread wheat), contains 6 heat stress transcription factors (HSFC1b, HSFB2a, HSFB2b, HSFA3, HSFA5 and HSFA9; Seni et al, 2021), which can be used in breeding programmes of wheat for HT tolerance at reproductive stage (Jakhu et al, 2021). Likewise, in emmer wheat, the alleles (Ppd-A1) are associated with early flowering (Nishimura et al, 2018), while the QTL that suppressed the late flowering in emmer wheat was detected on 7B chromosome and is linked to the Vrn-B3 gene (Wright et al, 2020), which will be helpful in protecting plant from male sterility during HT stress. Similarly, in rice, Cao et al (2022) found a QTL (qHTH5) in Oryza rufipogon at chromosome 5 and transfered it to Oryza sativa, which increased the tolerance in O. sativa at the heading stage, while its suppression increased its susceptibility to HT stress.…”