Male-sterile Triticum aestivum L. "Bison," possessing cytoplasm of T. timopheevi Zhuk., typically produces male-sterile progeny when pollinated with common wheat cultivars. A fertility restorer developed by transferring genes from T. timopheevi to T. aestivum produced fertile hybrids when used as the pollen parent in a cross with male-sterile Bison. Data on the F2 and testcross plants indicate that two dominant genes, designated Rf1 and Rf2, condition fertility in wheats with T. timopheevi cytoplasm.