Genetic Mapping by 55K Single-Nucleotide Polymorphism Array Reveals Candidate Genes for Tillering Trait in Wheat Mutant .

Background: The tiller number is a key agronomic trait for increasing the yield potential of wheat ( L.). A number of quantitative trait loci (QTLs) and key genes controlling tillering have been identified, but the regulatory mechanisms remain unclear.

Methods: In this study, we utilized the dwarf-monoculm mutant () obtained from the ethyl methane sulfonate (EMS)-treated wheat cultivar Guomai 301. The F populations were constructed using the mutant crossed to multiple tiller parents. The F populations were surveyed for tillering traits at the critical fertility stage for genetic analyses. The extreme-tillering-phenotype plants from the F population were used to construct mixing pools that were analyzed by a wheat 55K SNP array. The tillering genes of were mapped using the wheat 55K SNP array combined with transcriptomic data.

Results: The results showed that the genetic phenotype of is controlled by two dominant genes. The tillering genes of were mapped on the 60-100 Mb region of chromosome 5B and the 135-160 Mb region of chromosome 7A. A total of sixteen candidate genes associated with the tillering trait of were identified. Two candidate genes, TraesCS5B02G058800 and TraesCS7A02G184200, were predicted to be involved in indole acetic acid (IAA) response and transport, which were considered as potential regulatory genes.

Conclusions: This study elucidated the genetic basis of the mutant and provided two valuable reference genes for studying the development and regulatory mechanisms of wheat tillering.