Cytology and taxonomy of Elymus kengii, E. grandiglumis, E. alatavicus, and E. batalinii (Poaceae: Triticeae)

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 668-673 ◽  
Author(s):  
Kevin B. Jensen
Keyword(s):  
Central Asia ◽  
Chromosome Pairing ◽  
Morphological Variation ◽  
Interspecific Hybrids ◽  
Perennial Grasses ◽  
Taxonomic Changes ◽  
Tribe Triticeae

Elymus alatavicus (Drob.) A. Löve, E. batalinii (Krasn.) A. Löve, E. kengii (Keng) Tzvelev, and E. grandiglumis (Keng) A. Löve are rare hexaploid perennial grasses of the tribe Triticeae native to central Asia. This paper further describes the (i) genomic makeup of E. batalinii and E. alatavicus; (ii) chromosome pairing and fertility in hybrids between E. alatavicus or E. batalinii and E. kengii or E. grandiglumis; (iii) morphological variation among the taxa; and (iv) necessary taxonomic changes within Elymus necessitated by the above studies. On the basis of chromosome pairing in the hybrids E. batalinii × E. dentatus (Hook. f.) Tzvelev ssp. ugamicus (Drob.) Tzvelev, 10.21 I + 12.11 II + 0.18 III + 0.01 IV, and E. alatavicus × Pseudoroegneria tauri (Boiss. &Bal.) A. Löve, 13.10 I + 10.05 II + 0.52 III + 0.08 IV, the genomic formula for E. batalinii and E. alatavicus can be written as SSYYPP. Chromosome pairing in the hybrids E. alatavicus × E. grandiglumis, 9.37 I + 16.23 II + 0.06 III; E. kengii × E. batalinii, 10.25 I + 15.54 II + 0.21 III + 0.02 IV; and E. grandiglumis × E. batalinii, 9.15 I + 13.47 II + 1.09 III + 0.06 IV, combined with species morphology, supports the grouping of the above taxa in Elymus L. section Hyalolepis (Nevski) A. Löve rather than being separated in Elymus section Goulardia (Husnot) Tzvelev.Key words: genome, meiosis, chromosome pairing, interspecific hybrids, Elymus, Triticeae.

Cytogenetic analysis of interspecific hybrids and amphiploids between two diploid crested wheatgrasses, Agropyron mongolicum and A. cristatum

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1079-1084 ◽  
Author(s):  
Catherine Hsiao ◽  
Kay H. Asay ◽  
Douglas R. Dewey
Keyword(s):  
Chromosome Pairing ◽  
Morphological Variation ◽  
Reciprocal Translocation ◽  
Interspecific Hybrids ◽  
Diploid Species ◽  
Structural Rearrangements ◽  
Short Chromosome ◽  
Cytological Data ◽  
Broad Array ◽  
Pairing Behavior

Agropyron mongolicum Keng, the narrow linear-spiked diploid species (2n = 14), was hybridized with the broad pectinate-spiked diploid (2n = 14), A. cristatum (L.) Gaertner. The F1 hybrids were all diploids and morphologically intermediate to their parents. Chromosome pairing at metaphase I in the hybrids averaged 1.40 I, 5.59 II, 0.35 III, and 0.09 IV per cell, demonstrating that the two parental genomes are very similar. The F1 hybrids were partially fertile. The F2 progeny showed a broad array of variations in spike morphology and chromosome pairing behavior. Cytological data of the F1 hybrids and the F2 progeny revealed that these two diploid species contain the same basic P genome but differ by structural rearrangements of some chromosomes. The patterns of multivalent associations were the result of a heterozygous reciprocal translocation between a long and a very short chromosome segment. The colchicine-induced C0 amphiploids were fully fertile with regular chromosome pairing behavior. These two diploid species are the likely source of morphological variation in the tetraploid crested wheatgrasses.Key words: Agropyron, cytogenetics, chromosome pairing, interspecific hybrids.

CHROMOSOME PAIRING IN TWO INTERSPECIFIC HYBRIDS OF TRIFOLIUM

1970 ◽  
Vol 12 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Chi-Chang Chen ◽  
Pryce B. Gibson
Keyword(s):  
Phylogenetic Relationship ◽  
Chromosome Pairing ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Triploid Hybrid ◽  
Close Phylogenetic Relationship ◽  
Metaphase I

Both Trifolium repens (2n = 32) and T. nigrescens (2n = 16) formed bivalents during meiosis. However, their triploid hybrid showed an average of 4.27 trivalents per microsporocyte at metaphase I. The frequency of trivalents in the hybrid between T. nigrescens and autotetraploid T. occidentale (2n = 32) was 5.69. The data are interpreted to indicate: (1) a possible autotetraploid origin of T. repens; and (2) a close phylogenetic relationship among T. repens, T. nigrescens and T. occidentale.

scholarly journals A taxonomic revision of Gaultheria series Trichophyllae (Ericaceae)

2020 ◽  
Vol 14 (2) ◽  
pp. 289-341
Author(s):  
Peter W. Fritsch ◽  
Lu Lu
Keyword(s):  
New Species ◽  
Central Asia ◽  
Taxonomic Revision ◽  
High Elevation ◽  
Key To Species ◽  
East Central ◽  
Present Treatment ◽  
Taxonomic Changes ◽  
Species Descriptions ◽  
The Himalaya

The last taxonomic revision of Gaultheria series Trichophyllae (Ericaceae), a clade of high-elevation species endemic to the Himalaya-Hengduan Shan region of east-central Asia, was published in 1941. Since then, a number of new species have been described and other taxonomic changes have occurred in the group, prompting the need for a comprehensive revision. The present treatment of the series comprises 21 species, including Gaultheria x biluoensis, a newly described hybrid between G. crassifolia and G. major. A key to species and species descriptions is provided, and lectotypes are newly designated for G. cardiosepala, G. gonggashanensis, G. marronina, and G. stenophylla.

Evidence for genetic suppression of heterogenetic chromosome pairing in polyploidy species of Solanum, sect. Petota

1983 ◽  
Vol 25 (5) ◽  
pp. 530-539 ◽  
Author(s):  
Jan Dvořák
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Diploid Species ◽  
Diploid Hybrid ◽  
Polyploid Species ◽  
Chromosome Differentiation ◽  
Genetic Suppression ◽  
Solanum Sect ◽  
Paradoxical Results

Data on chromosome pairing in haploids and interspecific hybrids of Solanum, sect. Petota reported in the literature were used to determine whether the diploidlike chromosome pairing that occurs in some of the polyploid species of the section is regulated by the genotype or brought about by some other mechanism. The following trends emerged from these data. Most of the polyploid × polyploid hybrids had high numbers of univalents, which seemed to indicate that the polyploid species were constructed from diverse genomes. Haploids, except for those derived from S. tuberosum, had incomplete chromosome pairing. All hybrids from diploid × diploid crosses had more or less regular chromosome pairing, which suggested that all investigated diploid species have the same genome. Likewise, hybrids from polyploid × diploid crosses had high levels of chromosome pairing. These paradoxical results are best explained if it is assumed that (i) the genotypes of most polyploid species, but not those of the diploid species, suppress heterogenetic pairing, (ii) that nonstructural chromosome differentiation is present among the genomes of both diploid and polyploid species, and (iii) the presence of the genome of a diploid species in a polyploid × diploid hybrid results in promotion of heterogenetic pairing. It is, therefore, concluded that heterogenetic pairing in most of the polyploid species is genetically suppressed.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

Transfer of two South American ant species from Tapinoma Foerster 1850 to Forelius Emery 1888 (Hymenoptera: Formicidae: Dolichoderinae)

Zootaxa ◽  
2021 ◽  
Vol 4920 (3) ◽  
pp. 428-438
Author(s):  
ROBERTO J. GUERRER
Keyword(s):  
Morphological Variation ◽  
Taxonomic Status ◽  
Morphological Evidence ◽  
South American ◽  
Taxonomic Changes

Some species of the ant genus Forelius can be misclassified as the genus Tapinoma due to the convergent reduction of the petiolar scale. I review the taxonomic status of Tapinoma antarcticum Forel 1904 and Tapinoma heyeri Forel 1902. Morphological evidence supports the transfer of these names to the ant genus Forelius. Proposed taxonomic changes are as follows: Forelius antarcticus (Forel) comb. nov. (=Forelius fazi (Santschi 1923) comb. nov., =Forelius eidmanni Goetsch 1933 comb. rev.); Forelius heyeri (Forel) comb. nov. (=Forelius heyeri risii (Forel 1912) comb. and syn. nov., =Forelius pusillus (Santschi 1922) syn. nov., =Forelius tucumanus (Kusnezov 1953) syn. nov.). Lectotypes for Forelius antarcticus and Forelius heyeri are designated. The worker of Forelius heyeri, as well as the worker and queen of Forelius antarcticus are diagnosed and redescribed. Multifocus images for lectotype workers are provided. Morphological variation within and between species of Forelius with rounded spiracles is discussed. 

Genomic constitution of the allo-octoploid Elymus tenuis (Poaceae: Triticeae) of New Zealand

2010 ◽  
Vol 23 (5) ◽  
pp. 381 ◽  
Author(s):  
Hai-Qin Zhang ◽  
Xue Bai ◽  
Bao-Rong Lu ◽  
Henry E. Connor ◽  
Yong-Hong Zhou
Keyword(s):  
New Zealand ◽  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Genomic Constitution ◽  
Pollen Mother Cells ◽  
Mother Cells

Elymus tenuis (Buch.) Á.Löve et Connor is a perennial octoploid (2n = 56) wheatgrass endemic to New Zealand. To investigate its genomic constitution, four artificial interspecific hybrids between E. tenuis and E. enysii (2n = 4x = 28, HW), and E. solandri (2n = 6x = 42, StYW) and E. multiflorus (2n = 6x = 42, StYW) were studied cytologically. Meioses in pollen mother cells (PMCs) of the hybrids showed relatively high chromosome pairing, with an average of 13.50 in E. enysii × E. tenuis, 20.22 in E. solandri × E. tenuis, 19.62 in E. multiflorus × E. tenuis, and 20.00 in E. tenuis × E. multiflorus bivalents per cell, respectively. The results indicate that E. tenuis is an allo-octoploid species, with the new and unique genomic constitution StYHW. An autochthonous origin is proposed for it.

Systematics of the Freshwater Crayfish Genus Cherax Erichson (Decapoda: Parastacidae) in Northern and Eastern Australia: Electrophoretic and Morphological Variation

1996 ◽  
Vol 44 (3) ◽  
pp. 259 ◽  
Author(s):  
CM Austin
Keyword(s):  
Morphological Variation ◽  
Morphological Data ◽  
Morphological Evidence ◽  
Freshwater Crayfish ◽  
North West ◽  
The North ◽  
Species Analysis ◽  
Eastern Australia ◽  
Variable Species ◽  
Taxonomic Changes

A study of electrophoretic variation amongst 15 putative species of Cherax from northern and eastern Australia supported the recognition of only eight species. Analysis of morphological variation within these crayfish was largely consistent with the taxa identified electrophoretically, although variation in taxonomic characteristics was found to be far more extensive than was previously realised. Of the species identified electrophoretically, only C. dispar Riek and C. rhynchotus Riek are entirely consistent with the most recent taxonomic review of Cherax. The delineation of C. depressus Riek and C. wasselli Riek, although only partially consistent with the accepted geographic distributions of these species, is otherwise similar to the most recent taxonomic treatment. The major taxonomic changes supported by this study involve the delineation of C. cairnsensis Riek, C. cuspidatus Riek, C. destructor Clark and C. quadricarinatus (von Martens). Cherax cairnsensis, which could not be distinguished from the putative C. gladstonensis Riek and, in paa, C. wasselli and C. depressus, is an electrophoretically variable species with an extensive distribution along most of the east coast of Queensland from just north of Calms to just north of Brisbane. The species C. cuspidatus and C. neopunctatus Riek could not be clearly separated from one another and so support a more broadly defined C. cuspidatus. The four species that make up the 'C. destructor' complex (C. albidus Clark, C. davisi Clark, C. destructor Clark and C. esculus Riek) and C. rotundus Clark appear to be part of a single, morphologically variable, species, C. destructor. The redefinition of the northern Australian species C. quadricarinatus to include C. bicarinatus (Gray) from the north-west and C. albertisii (Nobili) from New Guinea is also supported on the basis of both electrophoretic and morphological data. Two species, C. punctatus and C. robustus Riek are more tentatively recognised solely on the basis of morphological evidence.

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