Fig. 3

Sequential fine-mapping of the major QTL-qGwc1.1. a Fine-mapping was conducted in the winter of 2015 in Hainan. b Fine-mapping was conducted in the summer of 2016 in Shandong. c Fine-mapping was conducted in the winter of 2016 in Hainan. d Fine-mapping was conducted in the summer of 2017 in Shandong. For each recombinant genotype (RG), the chromosomal region at QTL-qGwc1.1 is depicted as white (“844/844”), grey (“844/807”), and black (“807/807”) rectangles. Molecular markers in the heterozygous region were used to determine the genotypes of all progeny from each parental recombinant plant. The mean GWC values were calculated for various genotypes in the progeny. The t-test was used to determine the statistical significance of differences between GWC values among genotypes. In the right-side table, the heading “P-value” represents the difference between “844/844” and “807/807” in the self-cross populations and between “844/807” and “807/807” in the backcross populations. A P-value > 0.05 indicates that the GWC was not significantly different among genotypes and that the QTL-qGwc1.1 did not exist within the heterozygous region. A P-value < 0.05 indicates that the GWC were significantly different among genotypes and that the QTL-qGwc1.1 existed within the heterozygous region. The heading “Segregation” indicates whether the GWC significantly segregated or not among various genotypes within the progeny, where “S” denotes segregation (P-value < 0.05) and “NS” means non-segregation (P-value > 0.05). The heading “No. R” denotes the number of recombinants with the same genotype. The heading “No. P” denotes the number of plants. The heading “Marker” denotes the marker in the heterozygous region used for genotyping. The headings “844/844”, “807/807”, and “844/807” represent three different genotypes in the progeny. Four successive fine-mapping analyses narrowed the QTL interval from 22.72 Mb to 2.05 Mb