Department of Plant Pathology, Kansas State University, Manhattan 66506-5502, U.S.A.
The Rp8 rust resistance locus of maize is unique in that only Rp8-A/Rp8-B heterozygotes provide resistance and homozygotes are susceptible. A third allele, Rp8-C, provides no resistance in homozygotes or heterozygous combinations. Rp8 maps to the long arm of chromosome 6, near the restriction fragment length polymorphism marker umc21.
