Assessing the effect of inbreeding and long-distance gene flow on the invasive potential of Senecio pterophorus (Asteraceae)

2008 ◽  
Vol 56 (6) ◽  
pp. 539 ◽  
Author(s):  
Lidia Caño ◽  
Josep Escarré ◽  
José M. Blanco-Moreno ◽  
F. Xavier Sans
Keyword(s):  
Gene Flow ◽  
Inbreeding Depression ◽  
Seed Set ◽  
Spanish Population ◽  
Alien Invasive Species ◽  
Invasive Potential ◽  
Long Distance ◽  
Introduced Range ◽  
Self Compatibility ◽  
Introduced Population

Alien invasive species undergo genetic bottlenecks during the colonisation of new areas that can lead to a loss of genetic variation within populations and to subsequent reproductive constraints. We analysed the self-compatibility and the effects of inbreeding and inter-population gene flow in the fitness of one native and one introduced population of the invasive Senecio pterophorus D.C. Plants were self-pollinated and outcrossed within families, within populations, between local populations and between populations located in the native and introduced range. Self-pollinated individuals from both populations produced almost no seeds, thus revealing self-incompatibility. High family-level variation was observed in the effect of pollination treatment on seed set and total fitness. Overall, in the Spanish population, related crosses produced fewer seeds and lower germination rates than unrelated crosses. In the South African population, inbreeding depression affected the probability of flowering. Heterosis was found to affect seed set in both populations and growth and mean pre-reproductive time in the Spanish population. We discuss the effects of the incompatibility system, inbreeding depression and long-distance gene flow within the introduced population with respect to the invasive potential of S. pterophorus in north-eastern Spain.

Heterostyly in a tropical weed: the reproductive biology of the Turnera ulmifolia complex (Turneraceae)

1978 ◽  
Vol 56 (15) ◽  
pp. 1713-1725 ◽  
Author(s):  
S. C. H. Barrett
Keyword(s):  
Seed Dispersal ◽  
New World ◽  
Clonal Propagation ◽  
Seed Set ◽  
Reproductive Capacity ◽  
Weed Species ◽  
Long Distance ◽  
Floral Dimorphism ◽  
Self Compatibility ◽  
Turnera Ulmifolia

Turnera ulmifolia (Turneraceae) is a polymorphic complex native to the New World tropics which is composed of heterostylous and homostylous forms. The distylous varieties elegans, intermedia, and surinamensis exhibit the typical expression of heterostyly. Floral dimorphism is associated with a strong self-incompatibility system and size dimorphism of pollen. Approximately equal representation of floral morphs occurred in 24 out of 28 New World populations surveyed. In 9 out of 10 populations studied, there were no significant differences between the seed fecundity of floral forms. Populations of the homostylous variety angustifolia are self-compatible and produce monomorphic pollen.In contrast to the majority of heterostylous species, some varieties of T. ulmifolia are ruderal weeds. Varieties angustifolia, elegans, and intermedia are also used as garden ornamentals, and man has played a major role in the expansion of their ranges. Weediness in T. ulmifolia is not associated with features commonly found in other weed species, such as self-compatibility, vigorous clonal propagation, and long-distance seed dispersal. However, the continuous year-round flowering of T. ulmifolia plants gives populations a high reproductive capacity. Seed dispersal is by ants which transport seeds relatively short distances. Local seed dispersal favors the establishment of dense populations and increases the likelihood of seed set. Hence the dispersal system of T. ulmifolia appears to be coadapted with the population requirements of the breeding system.

scholarly journals Small arthropods as pollinators in a New Zealand pak choi field trial

2009 ◽  
Vol 62 ◽  
pp. 92-98 ◽  
Author(s):  
M.K. Walker ◽  
B.G. Howlett ◽  
J.A. McCallum ◽  
A.R. Wallace ◽  
D.A.J. Teulon
Keyword(s):  
Gene Flow ◽  
New Zealand ◽  
Body Length ◽  
Honey Bees ◽  
Seed Set ◽  
Long Distance ◽  
Pak Choi ◽  
Brassica Crops ◽  
Seed Crops

Brassica seed crops are grown throughout New Zealand and worldwide and intercrop and cropweed contamination through gene flow is a major concern For Brassica large arthropods (body length > 3 mm) particularly honey bees are the most important pollinators and are considered key vectors of pollen Small arthropods (body length < 3 mm) are also abundant in Brassica crops but their role as pollinators is rarely assessed Numerous small arthropods (particularly Diptera and Thysanoptera) were recorded within cages surrounding pak choi inflorescences that excluded large arthropods Inflorescences inside these cages set seed but seed set was significantly reduced compared with inflorescences in cages that were hand pollinated and uncaged inflorescences Although the presence of large arthropods significantly increased seed set the role of small arthropods and wind cannot be excluded in pak choi pollination Further studies are required to fully determine the role of small arthropods in long distance pollen flow

Self-compatibility and floral biology in subdioecious Wurmbea dioica (Colchicaceae)

2003 ◽  
Vol 51 (1) ◽  
pp. 39 ◽  
Author(s):  
Glenda Vaughton ◽  
Mike Ramsey
Keyword(s):  
Inbreeding Depression ◽  
Seed Set ◽  
Developmental Stages ◽  
Floral Biology ◽  
Seed Abortion ◽  
Temporal Separation ◽  
Gender Dimorphism ◽  
Genetic Method ◽  
Floral Longevity ◽  
Self Compatibility

Dioecy has long been interpreted as a mechanism to avoid self-fertilisation and the negative effects of inbreeding depression. We determined relative self-compatibility and temporal overlap of male and female functions for hermaphrodites in subdioecious Wurmbea dioica to assess the role of selfing in the maintenance of gender dimorphism. Plants were self-compatible but did not self-pollinate autonomously. Self- and open-pollinated hermaphrodites had high seed abortion and low seed set, whereas crossed hermaphrodites and crossed and open females had low seed abortion and high seed set. For selfed hermaphrodites, abortion occurred over a range of developmental stages and was negatively related to seed set. Inbreeding depression for seed set varied extensively among plants, averaging 0.56. Despite high inbreeding depression, substantial selfing occurred in open-pollinated hermaphrodites (S = 0.76), as estimated by a non-genetic method. Flowers were protogynous, although temporal separation of male and females functions was limited because anthers began to dehisce shortly after flowers opened. Anther dehiscence was staggered over 4 days and floral longevity, pollen longevity and stigma receptivity were prolonged, thus providing considerable opportunities for pollinator-mediated self-pollination. Our findings indicate that high levels of selfing and subsequent abortion of selfed embryos due to early acting inbreeding depression are important factors maintaining gender dimorphism in W. dioica.

Delayed autonomous selfing and inbreeding depression in the Australian annual Hibiscus trionum var. vesicarius (Malvaceae)

2006 ◽  
Vol 54 (1) ◽  
pp. 27 ◽  
Author(s):  
Leahwyn Seed ◽  
Glenda Vaughton ◽  
Mike Ramsey
Keyword(s):  
Inbreeding Depression ◽  
Pollen Germination ◽  
Seed Set ◽  
Pollen Grains ◽  
Reproductive Assurance ◽  
Selfed Progeny ◽  
Delayed Selfing ◽  
Hibiscus Trionum ◽  
Self Compatibility ◽  
Outcrossing Species

The Australian annual, Hibiscus trionum var. vesicarius, produces large, showy flowers typical of an outcrossing species, yet flowers autonomously self-pollinate. We used experimental pollinations to examine self-compatibility, inbreeding depression and the efficiency and mechanism of autonomous selfing. Seed set of self- or cross-pollinated flowers did not differ, indicating that plants were fully self-compatible. Seed set following autonomous selfing varied among plants, and was 11–103% of that following hand-selfing. Autonomous selfing was delayed, and styles curved and stigmas contacted the anthers before flowers closed. Delayed selfing was facultative and curvature depended on the number of pollen grains on stigmas, with 50 or more grains preventing curvature. Both self- and cross-pollen prevented curvature. Similarly to unpollinated styles, styles that were pollinated with dead pollen curved fully, indicating that either pollen germination or pollen-tube growth prevents curvature. Within flowers, the five styles acted independently, depending on the amount of pollination that each received. Although plants exhibit a high potential for selfing, crossed progeny outperformed selfed progeny and cumulative inbreeding depression was 0.64, which is high for a self-compatible annual. Despite this high inbreeding depression, delayed selfing would be advantageous under variable pollinator conditions, providing reproductive assurance.

Long distance pollen-mediated gene flow at a landscape level: the weed beet as a case study

2007 ◽  
Vol 16 (18) ◽  
pp. 3801-3813 ◽  
Author(s):  
STÉPHANE FÉNART ◽  
FRÉDÉRIC AUSTERLITZ ◽  
JOËL CUGUEN ◽  
JEAN-FRANÇOIS ARNAUD
Keyword(s):  
Gene Flow ◽  
Long Distance ◽  
Landscape Level

CORRELATED RESPONSE IN BROWN SARSON

1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao
Keyword(s):  
Gamma Irradiation ◽  
Seed Set ◽  
Previous History ◽  
The Self ◽  
Correlated Response ◽  
History Of ◽  
Self Compatibility ◽  
Selection For ◽  
Direction Opposite ◽  
Brown Sarson

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.

scholarly journals Camelina (Camelina sativa L. Crantz) Crop Performance, Insect Pollinators, and Pollen Dispersal in the Northeastern US

2019 ◽  
Author(s):  
Richard Rizzitello ◽  
Chuan-Jie Zhang ◽  
Carol Auer
Keyword(s):  
Gene Flow ◽  
Honey Bees ◽  
Pollen Dispersal ◽  
Camelina Sativa ◽  
Genetically Engineered ◽  
Oilseed Crop ◽  
Crop Failure ◽  
Long Distance ◽  
Insect Visitation ◽  
Pollinating Insects

AbstractCamelina sativa (camelina) is an oilseed crop in the Brassicaceae that has been genetically engineered for the production of biofuels, dietary supplements, and other industrial compounds. Cultivation in North America is both recent and limited, so there are gaps in knowledge regarding yield, weed competition, and pollen-mediated gene flow. For these experiments, camelina ‘SO-40’ was grown for three years without weed control. Spring-sown camelina was harvested at 80-88 days with ∼1200 growing degree days (GDD) with yields of 425-508 kg/hectare. Camelina yields were the same with or without weeds, showing competitive ability in low-management conditions. Crop failure in 2015 was associated with delayed rainfall and above-average temperatures after seeding. Camelina flowers attracted pollinating insects from the Hymenoptera, Diptera, Lepidoptera, and Coleoptera. Hymenoptera included honey bees (Apis melifera), mining bees (Andrenidae), sweat bees (Halictidae), bumble bees (Bombus spp.) and leaf cutter bees (Megachilidae). Insect visitation on camelina flowers was associated with modest increases in seed yield. Honey bees comprised 28-33% of all pollinators and were shown to carry camelina pollen on their legs. Air sampling showed that wind-blown pollen was present at low concentrations at 9 m beyond the edges of the field. These experiments demonstrated for the first time that camelina pollen dispersal could occur through honey bees or wind, although bee activity would likely be more significant for long-distance gene flow.

scholarly journals Spatial population genomics of a recent mosquito invasion

2020 ◽  
Author(s):  
Thomas L Schmidt ◽  
T. Swan ◽  
Jessica Chung ◽  
Stephan Karl ◽  
Samuel Demok ◽  
...  
Keyword(s):  
Gene Flow ◽  
Population Genomics ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Nucleotide Polymorphisms ◽  
Discrete Events ◽  
Long Distance ◽  
Population Genomic ◽  
Asian Tiger ◽  
Study Designs

AbstractPopulation genomic approaches can characterise dispersal across a single generation through to many generations in the past, bridging the gap between individual movement and intergenerational gene flow. These approaches are particularly useful when investigating dispersal in recently altered systems, where they provide a way of inferring long-distance dispersal between newly established populations and their interactions with existing populations. Human-mediated biological invasions represent such altered systems which can be investigated with appropriate study designs and analyses. Here we apply temporally-restricted sampling and a range of population genomic approaches to investigate dispersal in a 2004 invasion of Aedes albopictus (the Asian tiger mosquito) in the Torres Strait Islands (TSI) of Australia. We sampled mosquitoes from 13 TSI villages simultaneously and genotyped 373 mosquitoes at genome-wide single nucleotide polymorphisms (SNPs): 331 from the TSI, 36 from Papua New Guinea (PNG), and 4 incursive mosquitoes detected in uninvaded regions. Within villages, spatial genetic structure varied substantially but overall displayed isolation by distance and a neighbourhood size of 232–577. Close kin dyads revealed recent movement between islands 31–203 km apart, and deep learning inferences showed incursive Ae. albopictus had travelled to uninvaded regions from both adjacent and non-adjacent islands. Private alleles and a coancestry matrix indicated direct gene flow from PNG into nearby islands. Outlier analyses also detected four linked alleles introgressed from PNG, with the alleles surrounding 12 resistance-associated cytochrome P450 genes. By treating dispersal as both an intergenerational process and a set of discrete events, we describe a highly interconnected invasive system.

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