QTL Analyses of Yield and Yield-related Traits in Wheat Using a Mapping Population From a TAM 113/Gallagher Cross

Abstract

Understanding genetic architectures of yield and yield components of dryland and irrigated wheat (Triticum aestivum L.) is pivotal to developing modern high-yielding germplasm and cultivars, while maintaining end-use quality traits and tolerance to biotic and abiotic stresses. The aim of this study was to construct a genetic map and detect major quantitative trait loci (QTL) linked to yield and yield components using the biparental population developed from the cross ‘TAM 113’/’Gallagher’. Field studies including 191 recombinant inbred lines (RILs) were conducted at McGregor, College Station, and Bushland in Texas during the 2018-2019, 2019-2020, and 2020-2021 growing seasons. A set of 8,261 single nucleotide polymorphisms (SNPs) markers was used to construct a high-density genetic map for all 21 chromosomes using JoinMap 4.0. Genomic regions associated with yield and yield components were detected through linkage analysis and QTL identification using IciMapping. A total of 160 QTL were detected for all traits collected in the study. Among them, 10 QTL were detected at individual environments and 12 cluster QTL regions were identified. One major QTL was located at 34 Mb on chromosome 2D, affecting multiple traits including two consistent QTL for heading date (Qhd.tamu.2D.34) and plant height (Qph.tamu.2D.34), overlapping with the major photoperiod gene Ppd-1. Another cluster QTL, detected on 2 D at 37 Mb, was very close to a previously identified cluster controlling multiple traits, including yield and kernel area. Other important QTL clusters were located between 52 Mb and 66 Mb on 7D including one consistent QTL for grain yield at 52 Mbp that increased yield up to 24.16 g m-2, increased harvest index up to 1 % and increased kernel diameter by 0.03 mm. This study dissects genetic mechanisms associated with yield and its components, thus providing valuable information for wheat improvement.