Identification of the candidate gene controlling tiller angle in common wheat through genome-wide association study and linkage analysis

Abstract

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.