Inheritance of leaf peroxidase isoenzymes in Nicotiana alata and linkage with the S-incompatibility locus

Summary Genetic analysis of peroxidase isoenzymes observed by electrophoresis shows that each of the two cathodic bands are controlled by one gene, respectively, P_I and P_II. Each gene has two allele forms; presence of activity (dominant) and absence of activity (recessive). The same situation is found for one anodic band; the three other anodic bands are controlled by a single gene with three active allele forms. No progenies seem to be produced from gametes P _I ^- P _II ^- (no activity of P_I or P_II). Investigation of the incompatibility system and the isoperoxidases demonstrates that the loci P_I, P_II and S are located in the same chromosome. P_I is closely linked to the S locus (3 cM); the distance between P_II and the S locus is 34 cM.