Self-incompatibility of Zinnia angustifolia HBK (Compositae). II. Genetics

The genetics of self-incompatibility (SI) was studied in Zinnia angustifolia (2n = 2x = 22). A population of 14 full-sib F1 progeny was intercrossed in a full diallel and then was reciprocally backcrossed to both parents. Two intra-incompatible and reciprocally compatible classes were obtained in the F1 diallel. Among the backcrosses, one class consisting of six F1 progeny was reciprocally cross-compatible with parent 1 and reciprocally cross-incompatible with parent 2, whereas the second class consisting of eight F1 progeny was reciprocally cross-compatible with parent 2 and reciprocally cross-incompatible with parent 1. Three F2 and four BC1 families were generated and tested for incompatibility responses. The results of the crosses were consistent with a one-locus, multiallelic sporophytic SI system. The data suggest the presence of a linear dominance series of S-alleles in the pollen and either a linear dominance series or a combination of dominance and independent action of S-alleles in the pistil.