Identification and validation of a novel tiller inhibition locus (tin7) on chromosome 2BL in wheat

https://link.springer.com/article/10.1007/s11032-025-01567-z

Molecular Breeding，Volume 45, article number47, (2025)

Shuai Hou,Yuzhou Mou,Haojie Li,Caixia Li,Zhiqiang Wang,Yu Lin,Yueyue Liu&Yaxi Liu

Abstract

Tiller number is a key determinant of the number of spikes per plant, significantly influencing yield. Here, we identify and characterize a novel tiller inhibition line, N2496. Using an F2segregating population derived from crossing N2496 and CN16, we mapped this locus. The F1line demonstrated a high number of tillers, while the F2population exhibited segregated ratios of 3:1 in tiller number. BSR-Seq analysis indicated that only one locus controls tiller number, located on chromosome 2B (Chr. 2B). This genetic analysis confirmed the presence of a single recessive locus controlling the tiller inhibition trait within this population. Subsequently, we constructed a genetic map on Chr. 2B using a wheat 55 K single nucleotide polymorphism array. By combining recombinant analysis with the genotype and phenotype of the F2-3family, we identified and named a major and novel locus,tiller inhibition gene(tin7), mapped within a 2.43 cM interval. The influence oftin7was verified across six different background populations all sharing N2496 as a common parent. Using new recombinant lines from these six populations, we further narrowed down the interval oftin7to a genetic interval of 2.08 cM. Analysis of thousand grain weight and grain-related traits suggests that by regulating tiller number,tin7holds the potential to increase yield in wheat. Our research provides access to a novel tiller number locus and available markers for regulating tiller number, which could be used in developing new cultivars with an optimal number of tillers.