To evaluate the performance of wheat plant height and spike-related traits under delayed sowing conditions, a screening trial was conducted for wheat germplasm that exhibits resistance to late sowing and early maturity. The differences and stability of plant height and spike-related traits under different sowing dates were analyzed using 327 wheat germplasm sources from a wide range of areas. The results showed that mean values of wheat plant height and spike-related traits generally decreased along with the delay in sowing dates. Broad-sense heritability of plant height (PH), internode length below spike (ILBS), spike length (SL), spikelet per spike (SPS), and spike number (SN) under multiple environments were all above 85%. Ten varieties, including Xiangmai 35, Pingyang 27, Huaimai 23, Huaimai 22, Emai 6, Zhenmai 12, Xiaoyan 81, Shannong 7859, Annong 1589, and Shuiyuan 86 indicated stable performance under different sowing dates, which harboring good resistance to late sowing. The results of this study laid a foundation for breeding high-yield wheat varieties that are resistant to late sowing.

Waterlogging is becoming a global issue, affecting crop growth and yield in low-lying rainfed areas. A DH line, TamF169, showing superior waterlogging tolerance, and its waterlogging-sensitive parent, Franklin, were used to conduct transcriptome analyses. The results showed that 2209 and 2578 differentially expressed genes (DEGs) in Franklin and 1997 and 1709 DEGs in TamF169 were detected by comparing gene expression levels under control and waterlogging after 4 and 8 days, respectively, with 392 and 257 DEGs being specific to TamF169 after 4 and 8 days under waterlogging, respectively. KEGG analysis showed that glycolysis/gluconeogenesis, the MAPK signaling pathway, plant hormone signaling, and galactose metabolism pathways were significantly enriched in the waterlogging-tolerant genotype TamF169 four days after waterlogging. The qPCR results were consistent with the transcriptome data, suggesting the reliability of the transcriptome sequencing. A total of 13 genes in the mapping region of a QTL for root cortical aerenchyma (RCA) showed different expression levels in Franklin or TamF169, and the potential candidate genes for RCA−QTL are discussed. This study offers valuable information on the mechanism of tolerance to waterlogging stress in the DH line TamF169 and provides the candidate genes for RCA−QTL.

Plant height and leaf morphology are considered complex agronomy traits; both are significantly related to nutrient utilization, lodging resistance, and photosynthetic efficiency, which ultimately affect biomass and yield. However, the molecular mechanism of leaf morphogenesis is still unclear. WOX is a group of plant-specific transcription factor families that regulate growth and development, cell division, and differentiation in plants. In the present study, we identified and characterized the m-876 mutant in barley (Hordeum vulgare L.), which exhibited an extreme reduction in leaf width and plant height. Using a map-based cloning strategy, the m-876 mutant was narrowed down to an 11.4 Mb genomic interval on the long arm of chromosome 5. By analyzing the gene annotation information and nucleotide sequences, we found that HvWOX3A (HORVU.MOREX.r3.5HG0467090) had a G-to-A substitution at the second exon in the m-876 mutant, resulting in a change of the coding amino acid from Tryptophan to a premature stop codon at the 200th amino acid position. Remarkably, the mutation of the HvWOX3A gene leads to changes in gene expression in the m-876 mutant. Collectively, our results indicate that the loss function of the HORVU.MOREX.r3.5HG0467090 gene might be responsible for the phenotypic variation in barley mutants.

Mutagenesis is an important tool in crop improvement and free of the regulatory restrictions imposed on genetically modified organisms. Barley (Hordeum vulgare L.) is a diploid species with a genome smaller than those of other members of the Triticeae crops, making it an attractive model for genetic studies in Triticeae crops. In this study, we report an ethyl methane sulfonate (EMS)-mutagenized population in the Chinese barley landrace TX9425, which is tolerant to both abiotic and biotic stress. A TILLING (Targeting Induced Locus Lesion in Genomes) population consisting of 2000 M₂ lines was also constructed based on the CEL I enzyme with subsequent polyacrylamide electrophoresis, which decreased the cost and labor investment. The mutant phenotypes of the M₂ and M₃ generations were scored and revealed the presence of a wide spectrum of morphological diversity. The population was evaluated by screening for induced mutations in five genes of interest. A detailed analysis was performed for the HvGLR3.5 gene and three mutations were identified by screening in 2000 M₂ lines. Two of three mutations displayed tuft and yellow striped leaves compared to the wild type. Altogether, our study shows the efficiency of screening and the great potential of the new TILLING population for genetic studies in the barley crop model system.

Barley (Hordeum vulgare L.) is resistant to salt, drought and low temperature stress but sensitive to waterlogging stress. For now, little is known in waterlogging stress about the molecular mechanisms underlying the regulation of hormonal pathways in barley roots. In this study, the effects of waterlogging stress on 33 genotypes during the whole growth stages were comprehensively assessed. Then, the root morphology, hormone content and relative root development gene expressions were investigated in the most waterlogging-sensitive and -tolerant genotypes. We found waterlogging-tolerant genotypes (four representative genotypes) increased root length, forks, surface and project area traits at the early stage of waterlogging stress; meanwhile, these root traits were reduced in waterlogging-sensitive genotypes (four representative genotypes) because of ABA and ethylene inhibition. Furthermore, waterlogging-tolerant barley genotypes, respectively, induced and inhibited the positive (TCP20 and PLT2) and negative (SHY2 and PILS2) regulated gene’s expressions that controlled the meristem growth at the root tips to cope with waterlogging stress. In addition, our results were consistent with the hypothesis that waterlogging-tolerant barley genotypes can simultaneously upregulate GA levels and downregulate ethylene accumulation, which may induce the expression of SHR and SCR genes and enhance root growth under waterlogging stress. This research lays a foundation for the subsequent screening and breeding of waterlogging-tolerant genotypes and the exploration of waterlogging-tolerant mechanisms in barley.

Grain protein content (GPC) is a key quality trait in wheat, determining both nutritional value and end-use functionality, yet its genetic architecture is complex and highly influenced by the environment. In this study, a diverse panel of 327 wheat accessions was evaluated for GPC across multiple environments. Significant phenotypic variation was observed, with best linear unbiased estimates (BLUEs) ranging from 12.80% to 18.79%, and a moderate broad-sense heritability (h² = 0.52) was estimated. Genotype-by-environment interactions were highly significant. Genome-wide association analysis using the FarmCPU model identified seven stable quantitative trait nucleotides (QTNs) associated with GPC on chromosomes 1A, 1B, 2A, 2D, 3B, 5A, and 6A. Among these, QGpc.yzu-2A was consistently detected in three environments. Further analysis of the QGpc.yzu-2A region identified 26 annotated genes, 8 of which were expressed in grains. One gene, TraesCS2A02G473000 (RNA-binding protein), exhibited high nucleotide diversity and is a strong candidate for functional validation. Additionally, QGpc.yzu-6A co-localized with the known TaNAM-6A gene, reinforcing the role of this region in GPC regulation. This study provides valuable insights into the genetic basis of GPC in wheat and offers molecular markers and candidate genes for marker-assisted selection to improve grain protein content in breeding programs.