Fine mapping of the BPH15 locus. A, The marker positions of four previously mapped BPH resistant genes. B, Screened recombinant information in the BC2F2 family. Numbers under the linkage map indicate the number of recombinants detected between the marker and BPH15. BPH15 was mapped to the region between markers g12140-2 and T6. C, Recombination frequencies between each adjacent DNA marker. The dashed line represents genome average 0.004 cM/kb value. D, Physical map assembled by PCR-screened BAC clones. The dashed line represents the gap where no BAC clones overlapped.