BSR-seq for mapping restore-of-fertility genes of CMS in maize

There are three types of cytoplasmic male sterility (CMS) in maize, such as CMS-C, CMS-S, and CMS-T. Male sterility caused by the male-sterile genes in the mitochondrial genome can be overcome by the restore-of-fertility (Rf) genes encoded in the nucleus. To mapping and identifying the three main Rf genes for the three maize CMS, RfC for CMS-C, Rf3 for CMS-S, and Rf1 for CMS-T, we constructed 2 F2 (C-LH143/Ky21 and T-Mo17/Ky21, maternal plant/parental plant) and 3 BC1 [C-LH143/(C-LH143/Ky21), (S-Jing724/Ky21)/N-Jing724, and T-Mo17/(T-Mo17/Ky21)] populations through crossing the three male sterilities with the restorer line Ky21 which harbors the three Rf genes. Another BC1 population [(S-Jing724/Jing92)/N-Jing724] was generated by crossing S-Jing724 and Jing92, the later line has the Rf3 gene. Young tassels of male-sterile plants and fertile plants of each aforementioned genetic population were collected to form the sterile pool and fertile pool, respectively. BSR-seq was performed with these pooled RNAs to mapping Rf genes.