Hybridization technology has proven valuable in enhancing yields in many crops, but was only recently adopted in the small grain cereals. Hybrid varieties in barley ( Hordeum vulgare ) rely on the cytoplasmic male sterility (CMS) system msm1 derived from Hordeum vulgare ssp. spontaneum . The major restorer gene described for the msm1 system is known as Rfm1 and maps to the top of chromosome 6H. To gain further insight into mec...