Identification of a BIBAC clone that co-segregates with the petunia Restorer of fertility (Rf) gene

Molecular markers closely linked to the Restorer of fertility (Rf) locus in petunia were sought by conducting a bulk segregant analysis. The co-segreg ation of markers and Rf was tested on a large BC1 population produced from two different parental lines carrying Rf. The recombination frequency betwe en OP704 and ECCA/MACT, the two most distal markers utilized in the fine-sc ale mapping, was significantly different in populations derived from parent s that carry different nuclear backgrounds. The fine mapping identified an amplified fragment length polymorphism (AFLP) marker that co-segregates wit h Rf. A petunia BIBAC library (four genome equivalents), with an average in sert size of 70 kb, was constructed and screened with the linked marker. A contiguous map was constructed from three different BIBAC clones that hybri dized to the marker. As a result, we have identified a 37.5-kb BIBAC clone that co-segregates with Rf.