2019 Volume 2019 Issue 2 Pages 57-62
Suzumaru R was developed by introducing three resistant genes against soybean cyst nematode, namely, rhg1, rhg2, and Rhg4 into Suzumaru by backcrossing six times and marker-assisted selection. In the present study, we performed whole genome re sequencing of the soybean varieties Suzumaru and Suzumaru R and compared the sequence for isogeneity confi rmation of the genetic backgrounds of the varieties. At the genome level, Suzumaru and Suzumaru R were found to have the same genetic background, using a sliding window analysis, except for three fragments, each of which contained rhg1, rhg2, or Rhg4, and a 3.6-Mb fragment at the end of chromosome 5. In the breeding process, the end of chromosome 5 was intentionally selected for soybean dwarf virus resistance (Rsdv1) from the donor parent in the BC6F1 to BC6F4 generation. However, plants having Rsdv1 showed unfavorable traits, and therefore, plants that did not have Rsdv1 were selected eventually. This small fragment on chromosome 5 might be a remnant region. Thus, whole-genome re-sequencing can be a powerful tool for in-depth analyses of the difference between two varieties. Applying this technology to backcross breeding would enable “precision breeding.”
