Physical mapping of a fertility-restoring gene against Aegilops kotschyi cytoplasm in wheat

Deletion mapping was conducted to locate a fertility-restoring gene (Rfv1) of common wheat (Triticum aestivum L. em. Thell) against the male-sterility-causing cytoplasm of Aegilops kotschyi Boiss. Since this gene had been known to be located on the satellited short arm of chromosome 1B of a common wheat cultivar Chinese Spring, we first produced alloplasmic deletion lines of Chinese Spring that had the cytoplasm of Ae. kotschyi and various sizes of deletions in the 1B short arm, and then studied their male fertilities. One of the deletion chromosomes, which lost 48% of the length of the 1B satellite, still carried the Rfv1 gene, but another deletion lacking 53% of the satellite did not. All the other deletions with larger deficiencies did not carry the gene. Thus, the Rfv1 gene was located within a 5% region of the 1B satellite, where an interstitial C-band is located.