Early inbreeding depression in the sexually polymorphic plant Dianthus sylvestris (Caryophyllaceae): Effects of selfing and biparental inbreeding among sex morphs

Abstract

Predominantly outcrossing plant species are expected to accumulate recessive deleterious mutations, which can be purged when in a homozygous state following selfing. Individuals may vary in their genetic load because of different selfing histories, which could lead to differences in inbreeding depression among families. Lineage-dependent inbreeding depression can appear in gynodioecious species if obligatory outcrossed females are more likely to produce female offspring and if partially selfing hermaphrodites are more likely to produce hermaphrodites. We investigated inbreeding depression at the zygote, seed, and germination stages in the gynomonoecious-gynodioecious Dianthus sylvestris, including pure-sexed plants and a mixed morph. We performed hand-pollinations on 56 plants, belonging to the three morphs, each receiving 2-3 cross treatments (out-, sib- and self-pollination) on multiple flowers. Effects of cross treatments varied among stages and influenced seed provisioning, with sibling competition mainly occurring within outcrossed fruits. We found significant inbreeding depression for seed mass and germination and cumulative early inbreeding depression varied greatly among families. Among sex morphs, we found that females and hermaphrodites differed in biparental inbreeding depression, whereas uniparental was similar for all. Significant inbreeding depression levels may play a role in female maintenance in this species, and individual variation in association with sex-lineages proclivity is discussed.

Number of conspecifics and reproduction in the invasive plant Eschscholzia californica (Papaveraceae): is there a pollinator‐mediated Allee effect?

“…Additionally, smaller populations have shown a higher level of self-fertilisation, which can lead to uniparental inbreeding depression (Raijmann et al 1994;Courchamp et al 2008). Due to the effects of inbreeding depression, seeds from small populations may have a lower germination percentage and lower mass than seeds from larger populations (Menges 1991;Heschel & Paige 1995;Naito et al 2008;Collin et al 2009). This corresponds to a genetic Allee effect (Courchamp et al 2008).…”

Inbreeding depression in self-incompatible North-American Arabidopsis lyrata: disentangling genomic and S-locus-specific genetic load

“…Biparental inbreeding can be frequent in natural populations (Griffin and Eckert, 2003;Collin et al, 2009). For matings between full siblings, partners share half of their genome, so the level of biparental inbreeding depression is expected to be half of that due to selfing, which could help to purge the genetic load (Uyenoyama, 1986;Charlesworth and Charlesworth, 1987).…”

The Highly Heterozygous Homoploid Turfgrass Zoysia matrella Displays Desirable Traits in the S1 Progeny

“…However, self-pollination of Wakaba allowed the selection of S 1 progeny for their turf quality traits, such as higher ground covering, late winter dormancy, and fewer inflorescences than the parent Wakaba ( Table 2). The available literature indicates that forcibly self-pollinating outcrossing species can produce superior progeny that receive more advantageous alleles (Collin et al, 2009;Ahmed et al, 2010;Miti et al, 2010;Kawuki et al, 2011;Porta et al, 2014).…”