Association mapping identifies stable loci containing novel genes for developmental and reproductive traits in sorghum

Landraces are ideal for identifying genes related to adaptation. The purpose of this study was to map and identify genes related to adaptation. We evaluated a mini core collection that broadly samples the global sorghum landrace gene pool for 11 traits in 4–12 environments. Association mapping with 6094 317 SNPs identified 70 loci for the 11 traits. The key findings include two panicle weight (PWt) and two grain yield (GY) loci overlapped, and two panicle length (PL) and two panicle width (PW) loci overlapped. Some loci for tiller number (TL), PL/PW, PWt, GY, and seed weight (SW) colocalized with previously mapped quantitative trait loci. We identified 33 candidate genes for TL, PL, PW, PWt, GY, SW, and MRC. The overlapping PWt and GY locus on chromosome 9 contained gibberellin receptor GID1 gene that regulates seed development. A TL locus on chromosome 1 that was consistently detected contained Sobic.001G152700 encoding a DUF1618 protein that was the sole horizontally transferred gene from sorghum to the parasitic Striga hermonthica, which was potentially related to environmental adaptation. These results are relevant for sorghum molecular breeding. Future studies are needed to functionally characterize the rich collection of novel candidate genes identified in this study. Key message We mapped 11 sorghum traits, identified 33 candidate genes, and found a grain yield gene ( GID1) that regulates seed development and a grass-specific tillering gene (DUF1618) transferred to Striga hermonthica.