Kernel length (KL) is one of the components determining grain weight (GW) in wheat.  In this study, we firstly detected a putative locus on chromosome arm 2BL from a mutant BLS2 with long kernels using a Bulked Segregant Analysis (BSA) combined with a 60 K SNP array.  This putative locus was then confirmed as a major and stable QTL based on linkage mapping.  The locus, Qkl.sau-BC-2B.1, was mapped in an interval of 0.4 cM, and phenotypic variance explained by it varied from 17.01 to 30.53% across different environments.  Effects of this locus was further verified in a second population.  The positive allele of the locus could significantly increase hundred-kernel weight and prolong anthesis date, but it did not affect plant height, tiller number, spike length, and spikelet number per spike.  Expression and sequencing analyses identified TraesCS2B02G478100, possessing a G to C transition variation leading to an amino acid change, as the likely candidate gene underlying the locus.  Further, a new model for analyzing the genetic basis of yield-related traits was proposed. Taken together, our results provide a foundation for subsequent gene mining and breeding utilization of this promising QTL for KL.

Excessive cadmium (GrCdc) and deficiencies of copper (GrCuc) and magnesium (GrMgc) in grains pose serious human health risks.  Common wheat breeding has reduced genetic diversity within elite germplasm resources, negatively impacting future wheat production.  Thus, identifying loci controlling GrCdc, GrCuc, and GrMgc from tetraploid wheat and introducing them into common wheat is essential for genetic improvement.  In this study, we identified quantitative trait loci (QTL) for GrCdc, GrCuc, and GrMgc using the Wheat 55K single nucleotide polymorphism (SNP) array-based linkage map and phenotypic data across multiple environments in recombinant inbred lines derived from a cross between a wild emmer accession (LM001) and an endemic tetraploid wheat in Sichuan (Ailanmai).  Four major, stably expressed QTL were identified.  Three of these, including QGrCdc.sau-AM-5A for GrCdc, QGrCuc.sau-AM-4A for GrCuc, and QGrMgc.sau-AM-4A for GrMgc, were novel. These loci were validated using tightly linked Kompetitive Allele Specific PCR (KASP) markers in various genetic backgrounds. Several candidate genes (TRIDC5AG052690, TRIDC5BG060070, and TRIDC4AG008520) with sequence variations were predicted to influence Cd, Cu, or Mg absorption and transport within these QTL intervals.  Correlation analysis revealed that GrCdc was not correlated with GrCuc or GrMgc, although GrCuc was significantly correlated with GrMgc.  Furthermore, no significant effects of GrCdc, GrCuc, or GrMgc on agronomic traits were detected, as no correlation between them and any of the eleven agronomic traits investigated was observed.  Additionally, QGrCuc.sau-AM-4A colocalized with QGrMgc.sau-AM-4A, suggesting potential shared physiological and/or genetic control.  Altogether, these stably expressed QTL across environments provide theoretical guidance for further germplasm improvement and fine mapping.