ELF-INCOMPATIBILITY is the inability of a plant producing functional male and female gametes to set seed upon self-pollination. The best known genetic system effecting incompatibility in plants is that in which a single series of oppositional alleles governs pollen-tube growth, with pollen behavior under autonomous, or gametophytic, genetic control (EAST and MANCELSDORF 1926). Self-incompatibil...

A common yet poorly understood evolutionary transition among flowering plants is a switch from outbreeding to an inbreeding mode of mating. The model plant Arabidopsis thaliana evolved to an inbreeding state through the loss of self-incompatibility, a pollen-rejection system in which pollen recognition by the stigma is determined by tightly linked and co-evolving alleles of the S-locus receptor...