Fortunately, the SSR markers that flank Qfhs.ndsu-3BS allow us to use the considerable polymorphism information content (PIC) inherent in this marker type (Roder et al., 1995) to determine if FHB resistant lines are likely to contain this major QTL.
Twenty North American spring wheat cultivars (Table 3) of historical prominence (van Beuningen and Busch, 1997) were also used in this study to obtain a better estimation of the PIC values and allele distribution of the SSR markers near Qfhs.ndsu-3BS.
On the basis of the physical positions of three markers Xgwm389, Xgwm533 and Xgwm493, it was not clear whether Qfhs.ndsu-3BS is located between the breakpoints between deletion lines 3BS-3 and 3BS-8 or distal to the breakpoint of 3BS-3 (Zhou et al., 2000).
The Sumai 3 haplotype (haplotype 1) is rare, which is important for us to trace Qfhs.ndsu3BS with molecular markers.
Six FHB resistant lines, Jinshan88-102, CM-82036, Ning894037, CIMMYT14, Wuhan 3, and Fujian 5114, have the same genotype as that of Sumai 3 for all the five SSR markers, and therefore most likely contain Qfhs.ndsu-3BS.
Thus, these lines are unlikely to carry Qfhs.ndsu-3BS.
To avoid redundant mapping studies that are time-consuming and expensive, it is more reasonable to study germplasm that may not contain Qfhs.ndsu-3BS.