Single- and multi-locus genome-wide association study reveals genomic regions of thirteen yield-related traits in common wheat

Genetic dissection of yield-related traits can be used to improve wheat yield through molecular design breeding. In this study, we genotyped 245 wheat varieties and measured 13 yield-related plant height-, grain-, and spike-related traits, in seven environments, and identified 778 loci for these traits by genome-wide association study (GWAS) using single- and multi-locus models. Among these loci, nine were major, of which seven were novel, including Qph/lph.ahau-7A for plant height (PH) and leaf pillow height (LPH), Qngps/sps.ahau-1A for number of grains per spike (NGPS) and spikelet number per spike (SPS), Qsd.ahau-2B.1 and Qsd.ahau-5A.2 for spikelet density (SD), Qlph.ahau-7B.2 for LPH, Qgl.ahau-7B.3 for grain length (GL), and Qsl.ahau-3A.3 for spike length (SL). Through marker development, re-GWAS, gene annotation and cloning, and sequence variation, haplotype, and expression analyses, we confirmed two novel major loci and identified potential candidate genes, TraesCS7A02G118000 (named TaF-box-7A) and TraesCS1A02G190200 (named TaBSK2-1A) underlying Qph/lph.ahau-7A for PH-related traits and Qngps/sps.ahau-1A for spike-related traits. We also reported two favorable haplotypes, including TaF-box-Hap1 associated with low PH and LPH and TaBSK2-Hap3 associated with high NGPS and SPS. In summary, these findings can be applied to improve wheat yield and enrich our understanding of the complex genetic mechanisms of yield-related traits.