LOCALIZATION OF GENES IN RYE THAT RESTORE MALE-FERTILITY TO HEXAPLOIDWHEAT WITH TIMOPHEEVI CYTOPLASM

Four sets of wheat-rye addition lines were screened to localize genes in rye that restore male fertility to hexaploid wheat with timopheevi cytoplasm. One gene, designated Rfc3, was physically located in the di stal 40 % of the long arm of chromosome 6R. No allelic variation at Rf c3 was found; normal male fertility was consistently observed in all F 1 hybrid combinations tested. A second gene, designated Rfc4, was loca ted on the long arm of chromosome 4R. Variation between chromosomes 4R in the level of restoration was observed; fertility in hybrids ranged from 0 % to about 50 % of normal. Attempts to genetically map Rfc4 we re inconclusive but suggested it was located 16.1 cM from the telomere of the long arm and at least 8.0 cM from the centromere. These restor ers, particularly Rfc3, may have potential in hybrid wheat breeding pr ograms and can be manipulated for production of male sterile triticale lines.