Grain weight and size significantly influence wheat yield and quality. This study aimed to dissect the genetic basis of quantitative trait loci (QTL) associated with grain weight and size in hexaploid wheat (Triticum aestivum L.) using the novel wheat-Agropyron germplasm Pubing3228. A population of 210 F8 recombinant inbred lines derived from Pubing3228 and Jing4839 was evaluated across multiple environments for grain length, width, thickness and thousand-grain weight (TGW). Genotyping was conducted using the Illumina Infinium iSelect 55 K SNP chip, followed by QTL mapping with QTL IciMapping software. A total of 114 QTLs were identified across 20 wheat chromosomes, highlighting major QTLs for grain length, width/thickness and TGW. Candidate gene analysis revealed 22 genes expressed in grains, including those specifically associated with TGW, grain width/thickness and grain length. These findings enhance our understanding of the genetic mechanisms underlying wheat grain traits, providing insights for marker-assisted selection in wheat breeding programmes.
