Figure 2.

Assessment of the mode of mating (cross‐fertilization versus induced selfing) in heteroploid crosses of apomictic high polyploids upon self‐incompatible, tetraploid sexuals without emasculation based on the presence/absence of changes in the paternal genomic contribution to the embryos (and the endosperm) and changes in reproductive success compared to (tetraploid) homoploid crosses. Intercytotype cross‐fertilization will lead to a change in the paternal genomic contribution, whereas no change is indicative of progeny derived from selfing. (i) No differences neither in the paternal genomic contribution nor the reproductive success indicate full self‐compatibility (i.e., selfing of tetraploids), whereas (iv) an increase in the number of parental genomes without reduction in the reproductive success suggests full compatibility of cytotypes (i.e., relaxation of genomic endosperm balance requirement). In contrast, a reduction in reproductive success indicates selection against selfed and/or cross‐fertilized progeny (leading to abortion of seeds), that is, entails an ambiguous inference: (ii) reduced reproductive success, but no change in parental genomes indicates either complete selection against cross‐fertilized progeny (i.e., only selfed progeny developed into seeds) or selfing occurred and some selfed progeny was lost due to inbreeding depression. In contrast, (iii) change in the paternal genomic contribution accompanied by a reduction in reproductive success either indicates some selection against cross‐fertilized progeny or complete selection against selfed progeny