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.
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
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
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).