Wheat tiller angle (TA) is an important agronomic trait that contributes to grain production by affecting plant architecture. It also plays a crucial role in high-yield wheat breeding. An association panel and a recombinant inbred line (RIL) population were used to map quantitative trait loci (QTL) for TA. Results showed that 470 significant SNPs with 10.4%–28.8% phenotypic variance explained (PVE) were detected in four replicates by a genome-wide association study (GWAS). Haplotype analysis showed that the TA_Hap_4B1 locus on chromosome 4B was a major QTL to regulate wheat TA. Ten QTL were totally detected by linkage mapping with the RIL population, and QTA.hau-4B.1 identified in six environments with the PVE of 7.88%–18.82% was a major and stable QTL. A combined analysis demonstrated that both TA_Hap_4B1 and QTA.hau-4B.1 were co-located on the same region. Moreover, QTA.hau-4B.1 was confirmed by bulked segregant RNA-Seq (BSR-Seq) analysis. Phenotypic analysis showed that QTA.hau-4B.1 was also closely related to yield traits. Furthermore, TraesCS4B02G049700 was considered as a candidate gene through analysis of gene sequence and expression. This study can be potentially used in cloning key genes modulating wheat tillering and provides valuable genetic resources for improvement of wheat plant architecture.

Carfentrazone-ethyl and tribenuron-methyl, the two widely used herbicides for weed control in field crops, frequently cause phytotoxicity to wheat seedlings in the field. In this study, a total of 697 wheat accessions containing three panels were scanned using wheat 90 K and 660 K SNP arrays to identify important herbicide resistance loci. Genome-wide association study (GWAS) revealed 329 significant single-nucleotide polymorphisms (SNPs) with phenotypic variance explained (PVE) of 11.3% to 27.6%. Among these SNPs, 15 were detected in multiple environments and they were mainly distributed on chromosomes 1B, 2D, 5B, 5D, 6D, and 7D. Further analysis indicated that gHR-5B (467–587 Mb), gHR-7D (46–52 Mb), and gHR-1B (517–580 Mb) were important herbicide resistance loci in wheat. Linkage mapping in a bi-parental population detected one QTL (qHR-1B) with PVE of 7.44% to 8.28%. This is reliable locus because its physical position (554–566 Mb) overlapped with gHR-1B by GWAS in the genome of Chinese Spring. This study provided some herbicide-resistant germplasm and important genetic loci for identifying genes of common wheat.

In order to widen gene germplasm for kernel hardness in triticale, 60 synthetic hexaploid triticales were tested by the single kernel characterization system (SKCS) and secaloindoline alleles were identified by sequencing. Phenotyping showed that frequencies of soft, mixed and hard genotypes were 43.3%, 48.3%, and 8.4%, respectively. Genotyping identified three known secaloindoline-a alleles and four known secaloindoline-b alleles. Three new Sina-R1 alleles were designated Sina-R1d, Sina-R1e and Sina-R1f. Compared to Sina-D1c, Sina-R1d showed four point mutations causing changes in four amino acids, Sina-R1e had one point mutation causing an alanine to glycine substitution, and Sina-R1f possessed five point mutations but produced the same amino acid sequence as Sina-R1d. Two new Sinb-R1 alleles were discovered and designated Sinb-R1e and Sinb-R1f. Compared to Sinb-R1a, Sinb-R1e possessed a triplet-code insertion and four point mutations causing a cysteine insertion and two amino acid substitutions, and Sinb-R1f possessed three point mutations causing a cysteine insertion and a change of arginine to glycine. Association of hardness index with secaloindoline alleles indicated that SKCS of the Sina-R1d genotype was significantly lower than that of Sina-R1e, and Sinb-R1e was significantly lower than that of the Sinb-R1d genotype. A total of eight allelic combinations of secaloindoline genes were identified; Sina-R1d/Sinb-R1e and Sina-R1e/Sinb-R1d were relatively prevalent in the triticales surveyed. The results provide valuable information for further use of these germplasms in triticale breeding program due to the diverse polymorphism in secaloindoline genes.