Hybridization Between Eucalyptus obliqua L'hérit. And E. pulchella Desf

1983 ◽  
Vol 31 (3) ◽  
pp. 211 ◽  
Author(s):  
BM Potts ◽  
JB Reid
Keyword(s):  
Hybrid System ◽  
Parental Species ◽  
Principal Component ◽  
Pollen Parent ◽  
Putative Hybrid ◽  
Hybrid Progeny ◽  
Hybrid Swarm ◽  
Long Distance ◽  
Or Gene ◽  
Tasmanian Endemic

The present study provides the first evidence for the occurrence of natural hybrids between the wide- ranging species E. obliqua (series Obliquae) and the restricted Tasmanian endemic E. pulchella (series Piperitae). The progeny from one putative hybrid is shown to be intermediate between the progeny from the two parental species for virtually all characters examined. Principal component and likelihood analyses support this intermediacy of the hybrid progeny and suggest that no other species are involved in this hybrid system. The hybrid progeny shows greater variability than progeny from either parental species. Further, the hybrid tree has a lower seed output per capsule than trees of either parental species and therefore the hybrid tree appears to be at an evolutionary disadvantage. The two adult hybrids were found on the edge of shallow gullies on E. pulchella-dominated, north- facing slopes away from pure stands of E. obliqua. Some natural saplings outside the phenotypic range of either species were also found in the gullies. These results are most easily interpreted as suggesting that the intermediate trees examined originated from recent hybridization (possibly F1) following the migration of E. obliqua pollen into the range of E. pulchella. It is suggested that long-distance pollen migration of this type may be of evolutionary importance in allowing the colonization of suitable sites (in this case, small gullies) by advantageous genes or gene combinations from a distant species. The gene combinations of the pollen parent may be reselected from a segregating hybrid swarm.

The hybrid nature of Lycium ciliatum × cestroides (Solanaceae): experimental, anatomical, and cytological evidence

1995 ◽  
Vol 73 (12) ◽  
pp. 1995-2005 ◽  
Author(s):  
Luis Bernardello ◽  
Ivana Rodriguez ◽  
Laura Stiefkens ◽  
Leonardo Galetto
Keyword(s):  
Parental Species ◽  
Germination Rate ◽  
Principal Component ◽  
Putative Hybrid ◽  
Herbarium Specimens ◽  
Similar Data ◽  
Hybrid Breakdown ◽  
Cytological Evidence ◽  
Living Plant ◽  
Hybrid Nature

The hybrid nature of Lycium ciliatum × cestroides Hieron. is supported through experimental crosses. Using L. ciliatum Schlecht. as a female parent, 57% of crosses set fruit with hybrid seeds, whereas reciprocal crosses were unsuccessful. Seeds had a high germination rate (76%). F1 plants obtained agree with the herbarium specimens previously cited as putative hybrid and with a living plant we found in Córdoba (Argentina). Leaf, stem, and flower anatomy, karyotype composition, and chemical nectar composition were analyzed in the artificial and the natural hybrid. Results were compared with similar data on the parental species. Most of the studied features were intermediate between those of the parental species, as supported by principal component analysis. The origin of this hybrid may be due to pollen transfer mediated by bumblebees that occasionally visit both parental species. The distribution of the parental species overlaps in a wide Chaco region showing no spatial, environmental, or external reproductive isolating mechanisms. Results indicate there is a hybrid breakdown in the progeny of the hybrid that would restrict the natural interspecific gene flow. Key words: Lycium ciliatum × cestroides, hybrid, karyotype, anatomy, crosses, flower visitors.

Cryptic Lineages and a Population Dammed to Incipient Extinction? Insights into the Genetic Structure of a Mekong River Catfish

2019 ◽  
Vol 110 (5) ◽  
pp. 535-547 ◽  
Author(s):  
Amanda S Ackiss ◽  
Binh T Dang ◽  
Christopher E Bird ◽  
Ellen E Biesack ◽  
Phen Chheng ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Natural Populations ◽  
Principal Component ◽  
Flood Pulse ◽  
Mekong River ◽  
Effective Population ◽  
Long Distance ◽  
Genetic Lineages ◽  
Low Genetic Diversity ◽  
Population Size Estimates

Abstract An understanding of the genetic composition of populations across management boundaries is vital to developing successful strategies for sustaining biodiversity and food resources. This is especially important in ecosystems where habitat fragmentation has altered baseline patterns of gene flow, dividing natural populations into smaller subpopulations and increasing potential loss of genetic variation through genetic drift. River systems can be highly fragmented by dams built for flow regulation and hydropower. We used reduced-representation sequencing to examine genomic patterns in an exploited catfish, Hemibagrus spilopterus, in a hotspot of biodiversity and hydropower development—the Mekong River basin. Our results revealed the presence of 2 highly divergent coexisting genetic lineages which may be cryptic species. Within the lineage with the greatest sample sizes, pairwise FST values, principal component analysis, and a STRUCTURE analysis all suggest that long-distance migration is not common across the Lower Mekong Basin, even in areas where flood-pulse hydrology has limited genetic divergence. In tributaries, effective population size estimates were at least an order of magnitude lower than in the Mekong mainstream indicating these populations may be more vulnerable to perturbations such as human-induced fragmentation. Fish isolated upstream of several dams in one tributary exhibited particularly low genetic diversity, high amounts of relatedness, and a level of inbreeding (GIS = 0.51) that has been associated with inbreeding depression in other outcrossing species. Our results highlight the importance of assessing genetic structure and diversity in riverine fisheries populations across proposed dam development sites for the preservation of these critically important resources.

scholarly journals Testing hypotheses of hybrid origins for two seashore species of Carex section Phacocystis (Cyperaceae)

2020 ◽  
Vol 194 (1) ◽  
pp. 100-117
Author(s):  
Michael D Nowak ◽  
A Tiril M Pedersen ◽  
Anne K Brysting ◽  
Audun Schrøder-Nielsen ◽  
Reidar Elven ◽  
...  
Keyword(s):  
Clonal Propagation ◽  
Parental Species ◽  
Sequence Data ◽  
Genomic Data ◽  
Putative Hybrid ◽  
Genetic Structuring ◽  
Hybrid Species ◽  
Testing Hypotheses ◽  
Future Studies ◽  
Analytical Approaches

Abstract Taxonomists have proposed numerous hybrid species in plants, but to gain a better understanding of the role that hybridization may play in plant diversification, such taxonomic hypotheses must be tested using genomic data. In this study, we employ ddRAD sequence data to test taxonomic hypotheses of hybrid origins in Carex salina and C. ramenskii (Carex section Phacocystis). Sequence data from multiple Norwegian and Icelandic populations of the putative hybrid and parental species were generated for hundreds of ddRAD loci. These data were used to estimate geographical structuring of genetic diversity and admixture and to explicitly test for hybrid origins using several analytical approaches. Our results indicate recurrent hybrid origins for the populations of C. salina and C. ramenskii sampled in our study and show that these populations are characterized by high interspecific heterozygosity. Our results support the idea that hybridization may indeed play an important role in the diversification of lineages of Carex and highlight the important role that clonal propagation might play in maintaining hybrid populations. Future studies focusing on a broader geographical sampling would be needed to assess if the genetic structuring in these Nordic populations reflects range-wide patterns in these hybrid lineages.

Volatile oils and the study of natural hybridization between Correa aemula and C. reflexa (Rutaceae)

1977 ◽  
Vol 25 (3) ◽  
pp. 291 ◽  
Author(s):  
T Whiffin
Keyword(s):  
Numerical Analysis ◽  
Parental Species ◽  
Volatile Oil ◽  
Natural Hybridization ◽  
Volatile Oils ◽  
Hybrid Swarm ◽  
Hybrid Plants ◽  
Complex Variation

A small hybrid swarm between Correa aemula and C. reflexa was located and examined morphologically and chemically, with an emphasis on volatile oils. The hybrid plants were intermediate morphologically between the two parental species. The volatile oil data were subjected to multivariate numerical analysis, the results of which confirmed the general intermediacy of the hybrid plants. In general it was found that ordination is a more useful technique for the study of hybridization than is classification. It would appear that numerical analysis of volatile oil data will prove a useful technique in the study of the complex variation found within the genus Correa.

scholarly journals Chromosomal Pairing and Pollen Viability in Rhizophora mangle and Rhizophora stylosa Hybrids

2002 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Anand P. Tyagi
Keyword(s):  
Diploid Number ◽  
Parental Species ◽  
Pollen Viability ◽  
Rhizophora Mangle ◽  
Staining Technique ◽  
Putative Hybrid ◽  
Mangrove Species ◽  
Rhizophora Stylosa ◽  
Chromosomal Pairing ◽  
Very High

Two prominent mangrove species of Fiji, Rhizophora mangle, Linn. Rhizophora stylosa Griff and their puative hyubrid (R x selala) were analysed for chromosome number and pairing. Both parental species and their hybrid possess a diploid number of (2n) = 36 chromosomes. Regular 18 bivalents were observed in two species but the hybrid lacked proper chromosome pairing during meiosis. Analysis of tetrads showed normal tetrad and microspores development in parental species but very high abnormality in the hybrid. Pollen fertility determined by staining technique and pollen germination technique showed very high pollen viability in both parental species but very low pollen viability in the putative hybrid. Lack of chromosomal homology appears to be contributing to high percentage of non-viable pollen resulting in complete sterility in the putative hybrid.

Genetic status of the putative hybrid swarms of mountain dwarf pine and Scots pine in contact zones of their distribution in Slovakia

Biologia ◽  
2015 ◽  
Vol 70 (10) ◽  
Author(s):  
Peter Maňka ◽  
Andrej Kormuťák ◽  
Martin Galgóci ◽  
Dušan Gömöry
Keyword(s):  
Genetic Structure ◽  
Scots Pine ◽  
Molecular Level ◽  
Natural Populations ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Hybrid Swarm ◽  
Pure Species ◽  
Hybrid Swarms ◽  
History Of

AbstractGenetic structure of the mountain dwarf pine (Pinus mugo) and Scots pine (P. sylvestris) natural populations along with their 4 putative hybrid swarms in Slovakia were analyzed using 12 enzyme loci. The study aimed in evaluation of postulated hybrid status of the swarms on molecular level. Based on semidiagnostic allele frequencies of the MDH B, MDH C, 6PGDH B, ADH 1 and F-EST loci in their megagametophytes and vegetative buds, the conspicuous genetic differences were detected between P. mugo and P. sylvestris populations. The putative hybrid swarms seem to incline by their genetic structure to P. mugo rather than to P. sylvestris. Obtained results indicate independent developmental history of each of the scored hybrid swarms. The putative hybrid swarm in Sucha Hora was found to be a mixed stand consisting prevailingly of pure-species individuals of P. mugo and P. sylvestris. On the contrary, the putative hybrid swarms in Habovka, Tisovnica and Terchova are supposed to be of hybrid origin.

Analysis of a Hybrid Swarm Between Eucalyptus risdonii Hook. F. And E. amygdalina Labill

1985 ◽  
Vol 33 (5) ◽  
pp. 543 ◽  
Author(s):  
BM Potts ◽  
JB Reid
Keyword(s):  
Phenotypic Diversity ◽  
Flowering Phenology ◽  
Hybrid Swarm ◽  
Hybrid Fitness ◽  
Seedling Vigour ◽  
Pure Species ◽  
Closely Related Species ◽  
Intermediate Phenotypes ◽  
Disjunct Populations ◽  
Tasmanian Endemic

E. risdonii is a rare Tasmanian endemic which occurs as a series of small disjunct populations within a more-or-less continuous population of a closely related species, E. amygdalina. In localized areas (e.g. Risdon, Tasmania), patches of high phenotypic diversity are encountered, with individuals encompassing the complete phenotypic range between these two species. Progeny trials indicate a large heritable component to this variation. Open-pollinated progenies from intermediate mothers exhibit greater variability than those from either pure species, which strongly suggests that these intermediate phenotypes are a result of hybridization. Progenies from pure species mothers near a hybrid swarm are more variable than those from pure stands. There is a greater proportion of seedlings which match the artificially produced F1 in open-pollinated progenies from E. amygdalina than from E. risdonii mothers. In addition, progenies from intermediate mothers show a bias toward E. risdonii types, which implies that they are predominantly outcrossing to E. risdonii. This evidence suggests an asymmetrical flow of genes by pollen migration from E. risdonii into the hybrid swarm and surrounding E. amygdalina. Little difference in seedling vigour or mortality occurred between seedlings from the various parental phenotypes, although differences in seed output per capsule and germination were apparent. The specific identity of E. risdonii and E. amygdalina is usually maintained in parapatry by a range of mechanisms including their specific ecological preference, reduced hybrid fitness and differences in flowering phenology. The reasons for the major zones of hybridization occurring at boundaries on ridge tops as opposed to those on the dry slopes are discussed.

scholarly journals Biometrical study of some individuals chosen from Pinus mugo turra populations in the peat bog "Bór na Czerwonem"

2014 ◽  
Vol 64 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Alina Bączkiewicz
Keyword(s):  
Pinus Sylvestris ◽  
Parental Species ◽  
Growth Trait ◽  
Morphological Characters ◽  
Peat Bog ◽  
Pinus Mugo ◽  
Hybrid Swarm ◽  
Multivariate Statistical ◽  
One Year ◽  
Biometrical Study

Sixteen individuals were sampled for study of variation in 17 anatomical and morphological characters. Only individuals of low polycormic growth (trait typical for <i>Pinus mugo</i> Turra) connected with incurved one-year-cone stipes (a similar situation exists in <i>Pinus sylvestris</i> L.) were chosen, thus the sample studied cannot be treated as a random one. It has been shown by multivariate statistical analysis that these 16 individuals are quite different from each other, Mahalanobis'generalized distances between them being nearly 50% significantly different from 0. The sample studied in this respect is distinctly different from pure stands of both putative parental species (i.e. <i>Pinus mugo</i> and <i>P. sylvestris</i>). Every plant studied shows a different combination of traits typical (or nearly typical) for both the above-mentioned species and traits that are truly intermediate between them. The results support the frequently expressed opinion that the mountain pine population from the peat bog "Bór na Czerwonem" is, in fact, a hybrid swarm formed by hybridization between <i>Pinus mugo</i> and <i>Pinus sylvestris</i>.

scholarly journals The modern pollen–vegetation relationship in Jammu, India: a comparative appraisal

2021 ◽  
Vol 61 (1) ◽  
pp. 1-19
Author(s):  
Md. Firoze Quamar ◽  
Pooja Tiwari ◽  
Biswajeet Thakur
Keyword(s):  
Deciduous Forest ◽  
Principal Component ◽  
Pollination Syndrome ◽  
Fossil Pollen ◽  
Pollen Assemblage ◽  
Long Distance ◽  
Modern Pollen ◽  
Long Distance Transport ◽  
High Production ◽  
Pollen Records

An understanding of the relationship between modern pollen and vegetation is a prerequisite for reconstruction of vegetation and climate change from fossil pollen records. We conducted palynological studies of thirty-five surface soil samples from the Jammu region of India, which revealed that Pinus, among the conifers (regional needle-leaved taxa), is over-represented in the pollen assemblage due to its high production and effective dispersal of pollen. Other coniferous and broadleaved (regional and/or extra-regional) taxa have comparatively lower values in the pollen assemblages, similar to the representation of subtropical deciduous forest elements (regional), as well as shrubby (regional and/or extra-regional) taxa. This inconsistency in the pollen assemblage could be due to long-distance transport of the former by wind and/or water from the higher reaches of the Himalayas, and also because the latter have an entomogamous pollination syndrome and are not high pollen producers. The recovered pollen assemblage presents a distorted picture of the extant vegetation; hence, caution should be exercised in interpreting fossil pollen records from the study area. Principal component analysis (PCA) shows variability in the distribution of pollen from different sites in the Jammu region, perhaps the result of transport (by wind and/ or water), altitude and/or edaphic factors of the Himalayan terrain. The study should improve our understanding of the modern pollen-vegetation relationship and aid further calibration and interpretation of fossil pollen records.

Sign in / Sign up

Export Citation Format

Share Document