Genetic identification of a major, novel and stably expressed QTL for effective tiller number from tetraploid wheat

Effective tiller number (ETN) is an important factor affecting plant architecture and wheat yield. The reduction of genetic diversity in common wheat breeding forces us to explore new genetic resources for ETN from wheat related species to increase wheat yield. Here, a tetraploid wheat recombinant inbred line (RIL) population developed from the cross between a durum and a wild emmer accession was used to construct a genetic map using the wheat 55 K single nucleotide polymorphism (SNP) array. The map contained 1154 SNP markers with a total length of 2452.79 cM and an average density of 2.13 cM/marker. Quantitative trait locus (QTL) analysis identified a major and stably expressed QTL, <i>Qetn-DW-4B.1</i> for ENT, explaining 12.40–15.25% of the phenotypic variation. The favorable allele of this QTL was from wild emmer wheat and physically mapped in a 2.25 Mbp interval of 4BL containing 23 genes among which several were likely related to tiller development. Further comparison with previous studies showed that <i>Qetn-DW-4B.1</i> is likely a novel QTL. Genetic associations between ETN and other agronomic traits were also analyzed. Collectively, this study reported a major QTL for ENT from related species and lays a foundation to fine mapping and further wheat molecular breeding. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1996271 .