Figure 2.

Schematic of the affects of polyploidy on GSI in (A) the Solanaceae and (B) Prunus. In the Solanaceae, polyploidy directly causes the conversion from SI to SC due to the compatibility of heteroallelic pollen. In Prunus, polyploidy does not directly result in a breakdown of SI. Rather, SC requires the loss-of-function for a minimum of two S-haplotype-specificity components. Polyploidization creating tetraploid sour cherry presumably resulted from the mating of a 2n gamete from sweet cherry and an n gamete from tetraploid ground cherry (Iezzoni and Hancock 1984).