GENETICS AND MOLECULAR MAPPING OF A MALE-FERTILITY RESTORATION LOCUS (RFG1) IN RYE (SECALE-CEREALE L.)

A gene determining the restoration of cytoplasmic genic male sterility (CMS) caused by the Gulzow (G)-type cytoplasm was mapped by analyzing an F-2 and F-3 population comprising 140 and 133 individual plants, r espectively. The target gene, designated Rfg1, was mapped on chromosom e 4RL distally to three RFLP (Xpsr119, Xpsr167, Xpsr899) and four RAPD (XP01, XAP05, XR11, XS10) loci. Xpsr167 and Xpsr899 are known to be l ocated on the segment of chromosome 4RL which was ancestrally transloc ated and is homoeologous to the distal end of other Triticeae 6S chrom osomes. It is suggested that Rfg1 may be allelic to the gene determini ng the restoration of rye CMS caused by the Pampa (P) cytoplasm (chrom osome 4RL) and to Rfc4 that on rye addition lines of chromosome 4RL re stores male fertility of hexaploid wheat with T. timopheevi cytoplasm. Homoeoallelism to two loci for cytoplasmic-male-sterility restoration on chromosomes 6AS and 6BS in hexaploid wheat is also suggested.