cuspidata displays little propensity for autogamy or selfing and is primarily
self-incompatible; however, this is not uncommon for the Asteraceae (Ferrer and Good-Avila, 2007) and perennials in general (Duminil et al., 2009).
These results suggest emasculation in controlled hybridizations, even though passion fruit is
self-incompatible, mainly for genetic studies.
self-incompatible species (Abdalla & Hermsen, 1972).
For example, if chrysanthemum is
self-incompatible, the small central disk florets can be also used for production of hybrid seeds, because it is unnecessary to remove them.
in
self-incompatible species (i.e., dependent upon vectors of pollen), longevity of flower is longer than in self-compatible ones that are able to self-fertilize early after anthesis of flowers (primack, 1985; schoen and Ashman, 1995).
Plants that will not self-pollinate may be
self-incompatible or self-sterile.
The relationship between the self-compatibility and self-incompatibility alleles is described as S > [S.sup.h] > s with S the
self-incompatible (thrum) allele dominant to both [S.sup.h] for self-compatible (homostyly) and to s, the
self-incompatible (pin) allele.
Whether and to what extent individual species form asexual clones has important consequences on milkweed reproductive biology studies since self pollinations among wholly or partially
self-incompatible clones may affect levels of fruit set.
For example, it is observed in the
self-incompatible, wind-pollinated tree Alnus firma (Murakami and Maki 1992).
Moreover, both diploid and tetraploid Galax appear to be
self-incompatible. Finally, fruit production is comparable across cytotypes, with both having increased seed production in hand-outcrossed flowers suggesting pollen limitation.
Cherry laurel is a
self-incompatible species and needs cross-pollination for fruit set according to our observations.
The four o'clock family (Nyctaginaceae) contains both self-compatible and
self-incompatible species.