Self-incompatibility in Eucalyptus

Eucalypts are generally preferentially outcrossing (Pryor 1976; Griffin et a1 1987), with relatively high outcrossing rates (e.g. 0.69-0.84 Moran and Bell 1983) maintained by varying degrees of self-fertility (Pryor 1957, 1976; Hodgson 1976b; Griffin et a1 1987), aided by protandry (Pryor 1976) and reinforced by selection against the products of self-fertilization in later stages of the life cycle (see Potts et a1 1987). Most species exhibit a marked reduction in seed yield following self-pollination compared to outcrossing, although within species there is considerable variation in the level of self-fertility