Mating structure and inbreeding and outbreeding depression in the rare plant <i>Gentianella germanica</i> (Gentianaceae)

Fischer, Markus; Matthies, Diethart

doi:10.2307/2446466

Cited by 176 publications

(157 citation statements)

References 59 publications

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“…In such conditions recurrent consanguineous mating can lead to genetic purging (Pujol et al 2009), weakening inbreeding depression and opening potential for further increase of inbreeding. When fragmentation is due to ecological conditions, like in marginal habitats, inbreeding can be especially adaptive because it can help avoiding decreased fecundity (Fischer and Matthies 1997;Busch 2005;Mimura and Aitken 2007;Michalski and Durka 2007;Johnson et al 2009;Tollefsrud et al 2009). Nonetheless, because empirical studies provided a mixed support for this prediction, it was argued that in many cases populations experienced fragmentation only recently, so that the observed inbreeding level still reflects more the historical conditions rather than the reduced population size (Aguilar et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Population at the edge: increased divergence but not inbreeding towards northern range limit in Acer campestre

Chybicki

Waldon‐Rudzionek

Meyza

2014

Tree Genetics & Genomes

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Ecological conditions shape natural distribution of plants. Populations are denser in optimal habitats but become more fragmented in the areas of suboptimal environmental conditions. Usually, fragmentation increases towards the limits of species distribution. Fragmented populations are often characterised by decreased genetic variation, and this effect is frequent in peripheral populations, mostly due to the reduced effective population size. Interestingly, the genetic consequences of fragmentation seem to be relatively weak in forest trees. Using microsatellite markers, we assessed the impact of population fragmentation on the genetic structure of a European tree species Acer campestre. Within the study area, this medium-size wind-dispersed and insect-pollinated tree reveals a gradual decrease in population density towards the northern range limit. Over the distance of 150 km, we detected the significant decrease in allelic richness, heterozygosity as well as an increase in the rate of population divergence along with latitude. On the other hand, we failed to show that the observed patterns of genetic structure result from the variation in population densities. Moreover, inbreeding levels revealed no association with both density and geographic location, suggesting that pollen limitation does not occur, even at the range margin. As we showed that there is no difference in a dispersal scale between low-and highdensity populations in the study species, we argue that the genetic structure is a result of postglacial recolonization. However, unlike many other forest trees, A. campestre showed the sharp latitudinal genetic pattern at a very restricted spatial scale. Limited dispersal and high fragmentation are likely the reasons.

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Section: Discussionmentioning

confidence: 99%

Population at the edge: increased divergence but not inbreeding towards northern range limit in Acer campestre

Chybicki

Waldon‐Rudzionek

Meyza

2014

Tree Genetics & Genomes

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“…However, the risk of outbreeding depression increases with genetic differences between parents, and genetic differences are usually correlated with spatial distance. Fischer and Matthies (1997) and Waser and Shaw (2000) found the highest fitness in progeny from crosses between parents that were 10 m apart. Both lower (inbreeding depression) and higher distances (outbreeding depression) including interpopulation crosses, resulted in lower progeny fitness.…”

Section: Collecting Several Populations To Increase Genetic Diversity?mentioning

confidence: 99%

A question of origin: Where and how to collect seed for ecological restoration

Mijnsbrugge

Bischoff

Smith

2010

Basic and Applied Ecology

310

238

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Native plant species are routinely planted or sown in ecological restoration projects, but successful establishment and survival depend on where and how seeds are collected. Research suggests that it is important to use locally adapted seeds. Local populations often show a home-site advantage and non-local genotypes may be maladapted to local environmental conditions. Furthermore, intraspecific hybridisation of local and non-local genotypes may have a negative impact on the genetic structure of local populations via mechanisms such as outbreeding depression. Many species show a strong small-scale genetic differentiation between different habitats so that matching habitats of the restoration and donor site can be more important than minimizing geographical separation. It is a challenge to identify appropriate seed sources because strong small-scale population differentiation makes it difficult to delineate geographically defined seed zones to which seed exchange should be limited. Moreover, it is important to consider the genetic diversity of introduced material because it may be crucial to avoid genetic bottlenecks, inbreeding depression and poor establishment of plant populations. Repeated propagation in stock, which is often required to obtain a sufficient amount of seeds, can further reduce genetic diversity and may select for particular genotypes. Negative impacts of improper seed choice for nursery planting stock may become detectable only after many years, especially in long-lived and slow growing plants. Although scientific information on many species remains limited, the increasing demand for translocation of seed means that mandatory regulations are necessary. Guidelines should prescribe a specification of seed provenance, a record of genetic diversity of wild collections and rules for subsequent processing such as direct transfer and propagation of stock or seed orchards. We use a literature review to evaluate current legislation and to develop recommendations for herbaceous and woody species.

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“…This necessitates culling of inferior stock in the nursery to avoid high mortality or reduced growth in restoration plantings. The fitness costs of altered mating patterns, through changes in selfing and biparental inbreeding rates from alterations in tree density and spatial genetic structure, can perhaps best be unravelled through experimental pollinations over a range of distances (Fischer and Matthies, 1997). Few studies of tropical trees have explored the relationship between pollination distance and progeny fitness (Billingham, 1999;Stacy, 2001).…”

Section: Inbreeding Depressionmentioning

confidence: 99%

Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression

et al. 2013

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Habitat fragmentation is extensive throughout the world, converting natural ecosystems into fragments of varying size, density and connectivity. The potential value of remnant trees in agricultural landscapes as seed sources and in connecting fragments has formed a fertile area of debate. This study contrasted the mating patterns of bat-pollinated Pachira quinata trees in a continuous forest to those in pasture through microsatellite-based paternity analysis of progeny. The breeding system was determined by analysis of pollen tube growth and seed production from controlled pollinations. Fitness of selfed and outcrossed seed was compared by germination and seedling growth. There was more inbreeding within pasture trees (outcrossing ¼ 0.828±0.015) compared with forest trees (0.926±0.005). Pasture trees had fewer sires contributing to mating events, but pollen dispersal distances were greater than those in the forest. Paternity analysis showed variation in outcrossing rates among pasture trees with high proportions of external and self pollen sources detected. A leaky self-incompatibility system was found, with self pollen having reduced germination on stigmas and slower growth rate through the style. Controlled pollinations also showed a varied ability to self among trees, which was reflected in the selfing rates among pasture trees shown by the paternity analysis (0-80% selfing). Self pollination resulted in lower seed set, germination and seedling growth compared with outcrossing. While remnant trees in agricultural landscapes are involved in broader mating patterns, they show increased but varied levels of inbreeding, which result in reduced fitness.

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Mating structure and inbreeding and outbreeding depression in the rare plant Gentianella germanica (Gentianaceae)

Cited by 176 publications

References 59 publications

Population at the edge: increased divergence but not inbreeding towards northern range limit in Acer campestre

Population at the edge: increased divergence but not inbreeding towards northern range limit in Acer campestre

A question of origin: Where and how to collect seed for ecological restoration

Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression

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