GWAS for seed protein and oil concentration. Manhattan plots depicting the extent of the association of 31,954 SNPs, dispersed as shown over the 20 soybean chromosomes, with (A) mean seed protein content and (B) mean seed oil content of the soybean accessions, respectively. The-log P value is a measure of the degree to which a SNP is associated with the trait. SNP spikes topped by a red asterisk (*) denote a genomic region aligning with the location of a previously reported QTL, whereas those topped with the letter N denote that the region may harbor a heretofore unreported QTL. The vertical yellow bars spanning both graphs denote specific markers or a few markers in close proximity that exhibit significant association with both seed protein and oil content.