Fig 4. Additive effects of QTL for grain yield per spike (expressed in dg, red bars), number of kernels per spike (green bars) and kernel weight (expressed in mg, yellow bars) identified by GWAS in a tetraploid wheat collection (mean values across seven environments).

a) QTL for kernel number per spike associated to QTL for grain yield per spike; b) QTL for kernel number per spike associated to QTL for kernel weight in the opposite direction and without effects on grain yield per spike; c) QTL for kernel weight associated to QTL for grain yield per spike; d) QTL for kernel weight without significant effects on grain yield per spike. The positive or negative additive value refers to the SNP allele with higher frequency. * Significant at -log10(P) ≥3.0, ° significant at 2.0<-log10(P) <3.0.