Abstract
The Raphanus parent plants for this study were grown from seed collected from wild plants (weeds) in Nova Scotia, Canada, and in Poland. Analysis of 14 progenies showed that the specificity of self-incompatibility was controlled by S alleles at 1 locus. All but 1 segregation fitted a single gene ratio. Interactions of 8 S alleles included dominance in the stigma in 4 of the possible 28 heterozygotes, whereas dominance in the pollen was found in 18 of the 28 heterozygotes. The stigma dominance order was non-linear whereas a linear sequence with 4 levels of activity occurred in the pollen.