Because of this mode of reproduction, we asked whether
self-fertilization could occur when non-self sperm were also present.
The progeny from these crosses indicate that both high levels of outcrossing and
self-fertilization can occur in creeping bentgrass.
In some genetic models of the evolution of
self-fertilization, inbreeding depression plays a crucial role in determining whether or not selfing will be selectively favored (Lande and Schemske 1985; Charlesworth and Charlesworth 1987; Charlesworth et al.
Inbreeding depression (Sabbadin, 1971) is likely to exert selective pressure to prevent
self-fertilization, even though selfing would be a possible mechanism to assure fertilization in the narrow time window in which fertilization can produce functional embryos.
Do
self-fertilization and genetic drift promote a very low genetic variability in the allotetraploid Bulinus truncatus (Gastropoda: Planorbidae) populations?
membranacea zooids promotes cross-fertilization, but still allows
self-fertilization to occur.
Of the 70 maternal plants for which seed-set was estimated, the mean percent filled seeds for selfed and outcrossed flowers ranged from 0% to 94% and only three maternal plants (1 in population T4, 2 in population T26) exhibited higher mean seed-set upon
self-fertilization than cross-fertilization.
regnans there may be little selective disadvantage to
self-fertilization. First, excess pollen, and large numbers of small simple flowers and seeds, is a very low-cost reproductive strategy (Harper 1977).
In hermaphrodites, self-incompatibility produces differences in fertilization success that are similar in magnitude to among-species crosses, which could result in fairly strong selection pressures against
self-fertilization when non-self eggs are available.
The green dwarf coconut has slow growth, reproduction through
self-fertilization, greater precocity and produces a large number of fruits during the entire production period, in relation to the giant coconut.
Quantitatively, heterosis is measured by the difference between the value obtained in generation Ft and the mean value of the parents, being maximum in generation [F.sub.1] In diploid species, heterozygosis is expected to be reduced to half every
self-fertilization generation due to endogamy (WRIGHT, 1950).
Such isolation could occur as a consequence of changes in flowering time (Lumaret et al., 1987; Thompson and Lumaret, 1992; Ramsey, 2011), increased levels of
self-fertilization (Stebbins, 1950; Barringer, 2007) and/or changes in the activity and composition of pollinator communities (Thompson and Merg, 2008; Segraves and Anneberg, 2016).
