Fig. 1

ΔSNP index plots of each chromosome generated by QTL-seq analysis for use in Blp mapping. Each chromosome contains loci of expressed genes (1H: 4,300; 2H: 5,582; 3H: 5,556; 4H: 3,647; 5H: 5,859; 6H: 4,307; and 7H: 5,883) concatenating with intervals of 200-bp ‘N’ as a spacer. The ΔSNP index was obtained by subtracting the white bulk SNP index from the black bulk SNP index. The thick red line represents the sliding window average of the ΔSNP index (window size, 500 kbp; slide size, 10 kbp). The red arrow indicates the position of Blp as detected by Hori et al. [17]. Statistical confidence intervals under the null hypothesis of no QTL are indicated by yellow (p < 0.01) and green (p < 0.05) lines