RFLP mapping of the maize gametophytic restorer-of-fertility locus (rf3) and aberrant pollen transmission of the nonrestoring rf3 allele

Cytoplasmic male sterility (CMS) is the maternally inherited inability to produce functional pollen. The Rf3 allele of the nuclear gene rf3 gameto-phytically restores male fertility to maize plants with the S-type of CMS. The rf3 locus is on the long arm of maize chromosome two (2L). Using 2L RFLPs and three-point mapping analysis we showed that the rf3 locus is located an estimated 4.3 cM distal to the whp locus and 6.4 cM proximal to the bnl17.14 locus. This information was used in combination with RFLPs on two additional maize chromosomes to show that Rf3/rf3 CMS-S plants may aberrantly transmit the nonrestoring allele, rf3, through the male gametophyte.