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 F(2) segregating population derived from crossing N2496 and CN16, we mapped this locus. The F(1) line demonstrated a high number of tillers, while the F(2) population 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 F(2-3) family, we identified and named a major and novel locus, tiller inhibition gene (tin7), mapped within a 2.43 cM interval. The influence of tin7 was 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 of tin7 to a genetic interval of 2.08 cM. Analysis of thousand grain weight and grain-related traits suggests that by regulating tiller number, tin7 holds 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. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11032-025-01567-z.