Evidence of multiple allelomorphy at the incompatibility locus in Sorosporium consanguineum

Mating experiments between monosporidial lines ofSorosporium consanguineum from Mexico and the Pacific Northwest indicate that incompatibility in theAristida smut is controlled by multiple alleles at one locus. Alleles a₁ a₂ were demonstrated in a collection from Chihuahua, Mexico onAristida ternipes. It is hypothesized that these alleles also control incompatibility in collections of the smut from western United States. Alleles a₁ a₃ were detected in a collection from Durango Mexico onAristida divaricata. Apparently, this is the first time multiple alleles have been shown to control heterothallism inS. consanguineum.Scientific Paper No. 3541. Washington Agricultural Experiment Stations, Pullman, Project 1729.