CHROMOSOME NUMBERS OF SOME SOUTHWEST ASIAN SPECIES OF ASTRAGALUS AND OXYTROPIS (LEGUMINOSAE)

Ledingham, George F.; Rever, Beverley Maureen

doi:10.1139/g63-003

Cited by 30 publications

(17 citation statements)

References 6 publications

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“…2b). The present chromosome count of n=8 in the species is in agreement with the earlier records of 2n=16 from Ferozpur Nullah (1,950 m) locality in the Kashmir Himalayas (Gohil et al 1981, Ashraf andGohil 1989) and other parts of the Himalayas from India (Kumari et al 1989) and some parts of southwest Asia (Ledingham 1960, Ledingham andRever 1963, for Iraq andIran) (Figs 1a-c). Ashraf and Gohil (1989) have also studied the chiasma frequency in the species, and found a positive correlation between recombination indices and the total chromatin length.…”

Section: Meiotic Chromosome Numbersupporting

confidence: 91%

Impact of Reciprocal Translocations and Non-Synchronous Disjunction of Chromosomes on Pollen Fertility in Astragalus chlorostachys from the Northwest Himalayas (India)

et al. 2012

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Summary Cytological investigations carried out on a population basis in Astragalus chlorostachysLindl. which exists at diploid level (n=8) revealed the presence of quadrivalents, the late disjunction of 1-4 bivalents and some pollen sterility (34%) in 1 accession collected from Koksar, at 3140 m in the Lahaul Valley (Lahaul-Spiti, Himachal Pradesh). The presence of quadrivalents in this diploid species seems to be a consequence of reciprocal translocations. The occurrence of structural heterozygosity in the species has been reported here for the first time. All of the other populations showed normal bivalent formation and regular sporad generation and 100% pollen fertility. The paper here discusses in detail the course of meiosis and the effect of multivalent formation and non-synchronous disjunction of bivalents on meiotic course and pollen fertility.

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Section: Meiotic Chromosome Numbersupporting

confidence: 91%

Impact of Reciprocal Translocations and Non-Synchronous Disjunction of Chromosomes on Pollen Fertility in Astragalus chlorostachys from the Northwest Himalayas (India)

et al. 2012

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“…These results are in agreement with SHARAWY (2001) who placed this species with A. mareoticus (not studied here) in a separate group, where both the protein analysis and the combined characters were considered, but the analysis of the morphological and anatomical characters separated the two species from each other. Earlier LEDINGHAM & REVER (1963) confirmed the separation of the two species on the basis of chromosomal number, 2n = 28 for A. mareoticus and 2n = 16 for A. macrocarpus.…”

Section: And Badr and Sharawy (2007)mentioning

confidence: 63%

The interspecific relationships of Astragalus species in Egypt assessed by the morphoanatomical characters of the pod

Mourad

Sharawy

2010

Feddes Repertorium

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1The pod morphological and anatomical characters of 20 species, one sub-species and five varieties of Astragalus out of the 32 species growing in Egypt were investigated by light and scanning eletron microscopy, and numerically analysed to show the inter-as well as the infra-specific relationships. It was concluded that both A. trimestris and A. corrugatus show marked affinity to other species investigated in the present work.

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“…(sect. Onobrychoidei) is probably the highest count ever reported (Ledingham and Rever 1963). The above account indicates a significant role of polyploidy in the evolution of Old World Astragalus.…”

Section: Introductionmentioning

confidence: 70%

“…New World Astragalus species are almost exclusively aneuploids with a most frequent basic chromosome number n = 11, and polyploidy is virtually absent among them (reviewed in Spellenberg (1976) and Wojciechowski et al (1993)). The situation is markedly different in Old World species, where, besides the widespread diploid chromosome number 2n = 16, frequent counts of 2n = 32, 48, and 64 have been reported by cytological studies (Ledingham 1960;Ledingham and Rever 1963;Fedorov 1969;Philippov et al 2008;Masoud et al 2009). Ploidy levels might be phylogenetically determined, as observed by shared ploidy in closely related species.…”

Section: Introductionmentioning

confidence: 96%

Molecular evidence for reticulate speciation in Astragalus (Fabaceae) as revealed by a case study from sect. Dissitiflori

BarthaLászló

DragoşNicolae

Attila

et al. 2013

Botany

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Although hybridization has long been recognized as a major force driving speciation in land plants, it has not yet been evidenced in Astragalus, the largest angiosperm genus. Here, we reveal the possible contribution of hybridization to speciation in Astragalus by employing cloning of the nrDNA ITS region and sampling three plastid regions (ycf1, ndhF-rpl32, and rpl32-trnL) in taxa belonging to sect. Dissitiflori. Phylogenetic network and tree analyses uncovered various levels of intra-individual and intraspecific polymorphism of ITS in most of the taxa investigated. Two distantly related ribotype groups were found to be shared by the closely related polyploids Astragalus pallescens M.Bieb., Astragalus peterfii Jáv., and Astragalus pseudoglaucus Klokov suggesting ancient hybridization followed by incomplete lineage sorting (i.e., shared ancestral polymorphism) in nrDNA ITS. Reticulation is also invoked as an underlying evolutionary process behind the statistically highly supported incongruent placement of A. pseudoglaucus and Astragalus vesicarius subsp. pastellianus (Pollini) Arcang. in nuclear versus plastid phylogenies. The phylogenetic results also shed light on taxonomic controversies in the section, such as the false synonimization of A. peterfii under A. vesicarius s.l. Our results provide evidence for the (at least past) existence of speciation processes driven by hybridization in Astragalus.Key words: hybridization, ycf1, nrDNA ITS cloning, allopolyploidy, reticulation.Résumé : Bien qu'on ait reconnu depuis longtemps l'hybridation comme force majeure soutenant la spéciation chez les plantes terrestres, on n'en pas encore la preuve chez les Astragalus spp, le plus important genre des angiospermes. On évoque ici la contribution possible de l'hybridation à la spéciation des Astragalus spp., en utilisant le clonage de la région ITS du nrADN et en échantillonnant trois régions plastidiques (ycf1, ndhF-rpl32 et rpl32-trnL) chez des taxons de la section Dissitiflori. Le réseau phylogénétique et trois analyses révèlent divers degrés de polymorphisme intra-individuel et intraspecifique de l'ITS, chez la plupart des taxons examinés. On a repéré deux groupes de ribotypes partagés par l'Astragalus pallescens M. Bieb., l'Astragalus peterfii Jáv., et l'Astragalus pseudoglaucus Klokov, des polyploïdes étroitement reliées, ce qui suggère d'anciennes hybridations suivies de sélections de lignées incomplètes (i. e. polymorphisme ancestral partagé) dans l'ITS nrADN. On évoque la réticulation comme processus évolutif sous-jacent, également à la source de la localisation incongrue, fortement supportée statistiquement, de l'A. pseudoglaucus et de l'Astragalus vesicarius subsp. pastellianus (Pollini) Arcang. dans les phylogénies nucléiques versus plastidiques. Les résultats phylogénétiques éclairent les controverses sur la section, tel la fausse synonymie de l'A. peterfii sous l'A. vesicarius s.l. Les résultats fournissent la preuve (du moins dans le passé) de l'existence de processus de spéciation activés par l'...

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CHROMOSOME NUMBERS OF SOME SOUTHWEST ASIAN SPECIES OF ASTRAGALUS AND OXYTROPIS (LEGUMINOSAE)

Cited by 30 publications

References 6 publications

Impact of Reciprocal Translocations and Non-Synchronous Disjunction of Chromosomes on Pollen Fertility in <i>Astragalus chlorostachys</i> from the Northwest Himalayas (India)

Impact of Reciprocal Translocations and Non-Synchronous Disjunction of Chromosomes on Pollen Fertility in <i>Astragalus chlorostachys</i> from the Northwest Himalayas (India)

The interspecific relationships of Astragalus species in Egypt assessed by the morphoanatomical characters of the pod

Molecular evidence for reticulate speciation in Astragalus (Fabaceae) as revealed by a case study from sect. Dissitiflori

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