The effect of marker selection on fiber bundle strength (STR). Based on the genotypes of seven markers (QTLs), the 275 RILs of Set 2 (panel A) and all 550 RILs (panel B) were divided into two groups: 1) RILs containing 3 or more favorable alleles (Selected in red) and 2) the remaining RILs (Non-selected in black). The mean STR values of the selected and non-selected RILs were shown in red and black circle, respectively. The STR difference between the two groups was significant at p < 0.001. Y axis in g/tex.