Abstract
Meta-QTL analysis was conducted using 8,998 known QTLs, which included 2,852 major QTLs for grain yield (GY) and its following ten component/related traits: (i) grain weight (GWei), (ii) grain morphology related traits (GMRTs), (iii) grain number (GN), (iv) spikes related traits (SRTs), (v) plant height (PH), (vi) tiller number (TN), (vii) harvest index (HI), (viii) biomass yield (BY), (ix) days to heading/flowering and maturity (DTH/F/M) and (x) grain filling duration (GFD). The QTLs used for this study were retrieved from 230 reports (including 19 studies conducted in tetraploid wheat) that were based on 190 mapping populations (1999–2020). The study resulted in the identification of 141 meta-QTLs (MQTLs), with an average confidence interval (CI) of 1.37 cM (reduced 8.87 fold), the average CI in the initial QTLs being > 12.15 cM. As many as 63 MQTLs, each based on at least 10 initial QTLs were stable and robust; with 13 MQTLs are described as breeder’s QTLs. MQTLs were also utilized for the identification of 1,202 candidate genes (CGs), which included 18 known genes. The MQTLs were also found to contain 50 wheat genes that were homologous to 35 known yield-related genes from rice, barley, and maize. Further, the use of synteny and collinearity allowed the identification of 24 ortho-MQTLs which were common among the wheat, barley, rice, and maize. The results of the present study should prove useful for wheat breeding and future basic research in cereals including wheat, barley, rice, and maize. In particular, the breeder’s QTLs can be used for marker-assisted selection for grain yield and fine mapping leading to cloning of QTLs/genes for yield and related traits.