Karyotype analysis and genome relationships of 22 diploid species in the tribe Triticeae

1986 ◽  
Vol 28 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Catherine Hsiao ◽  
Richard R.-C. Wang ◽  
Douglas R. Dewey
Keyword(s):  
Chromosome Pairing ◽  
Karyotype Analysis ◽  
Diploid Species ◽  
Root Tip ◽  
Diagnostic Features ◽  
Genome Relationship ◽  
Microcomputer Program ◽  
Basic Set ◽  
Genome Content ◽  
Tribe Triticeae

Karyotypes were analyzed on 24 diploid taxa (mostly perennials) belonging to eight Triticeae genera, which are defined by genome content (basic set of seven chromosomes): (i) Agropyron (P genome), (ii) Thinopyrum (J genome), (iii) Secale (R genome), (iv) Hordeum (i genome), (v) Pseudoroegneria (S genome), (vi) Psathyrostachys (N genome), (vii) Australopyrum (W genome), and (viii) Critesion (H genome). In addition to traditional karyotype preparations, the metaphase root-tip chromosomes were analyzed by an interactive microcomputer program that printed an idiogram in which chromosomes were arranged by length. Genomes, arranged by decreasing length, are R, I, P, N, J, S, H, and W (with lengths ranging from 61.29 to 39.39 μm). Almost without exception, karyotypes of species within a genus manifest a pattern that is unique to the genome. Morphologically unique genomes are useful diagnostic features in genome identification and can complement interpretation of chromosome pairing in genome analysis.Key words: Triticeae, diploid, karyotype, genome relationship.

Genome analysis of Elytrigia caespitosa, Lophopyrum nodosum, Pseudoroegneria geniculata ssp. scythica, and Thinopyrum intermedium (Triticeae: Gramineae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R.-C. Wang
Keyword(s):  
Karyotype Analysis ◽  
Diploid Species ◽  
Pollen Grains ◽  
Root Tip ◽  
Meiotic Pairing ◽  
Tetraploid Species ◽  
Thinopyrum Intermedium ◽  
Male Sterile ◽  
Stainable Pollen ◽  
C Banding

To elucidate the genome constitutions of the tetraploid (2n = 4x = 28) species Elytrigia caespitosa, Lophopyrum nodosum, and Pseudoroegneria geniculata ssp. scythica and the hexaploid (2n = 6x = 42) Thinopyrum intermedium, meiotic pairing was studied in these species as well as 10 hybrids. Karyotype analysis with aceto-orcein stained root-tip cells was performed for the four species and the hybrids of T. bessarabicum with E. caespitosa, P. geniculata ssp. scythica, and T. intermedium. Karyotype analysis by Giemsa C-banding was carried out with the three tetraploid species and the two triploid hybrids involving T. bessarabicum. The species behaved as strict allopolyploids. All hybrids were male sterile with few stainable pollen grains. It is concluded from the results that the three tetraploid species have the genome formula JeJeSS and T. intermedium has the formula JeJeJeJeSS. The chromosomes of the Je and S genomes in these species had C-banding patterns differing from each other and from those of the extant diploid species. Based on these findings, the four species investigated should be placed in the same genus or the same section of a genus. However, new combinations are not proposed at this time pending future taxonomic investigation of the genome constitution of Elytrigia repens (L.) Nevski.Key words: genome, hybrid, meiosis, karyotype, chromosome banding, speciation.

CHROMOSOME RELATIONSHIPS BETWEEN THE CULTIVATED OAT AVENA SATIVA (6x) AND A. VENTRICOSA (2x)

1970 ◽  
Vol 12 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Hugh Thomas
Keyword(s):  
Chromosome Pairing ◽  
Avena Sativa ◽  
Diploid Species ◽  
Meiotic Behaviour ◽  
Hexaploid Species ◽  
C Genome

Chromosome pairing in the F1 hybrid between the cultivated oat Avena sativa and a diploid species A. ventricosa, and in the derived amphiploid, shows that the diploid species is related to one of the genomes of the hexaploid species. The amount of chromosome pairing observed in complex interamphiploid hybrids demonstrates further that A. ventricosa is related to the C. genome of A. sativa. However, the chromosomes of the diploid species have become differentiated from that of the C genome of A. sativa and this is readily apparent in the meiotic behaviour of both the F1 hybrid and the amphiploid.

Chromosome pairing and potential for intergeneric recombination in some hypotetraploid somatic hybrids of Lycopersicon esculentum (+) Solanum tuberosum

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1032-1041 ◽  
Author(s):  
J. H. de Jong ◽  
A. M. A. Wolters ◽  
J. M. Kok ◽  
H. Verhaar ◽  
J. van Eden
Keyword(s):  
Solanum Tuberosum ◽  
Lycopersicon Esculentum ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Somatic Hybrids ◽  
Cytogenetic Study ◽  
Unreduced Gametes ◽  
Root Tip ◽  
Prophase I ◽  
Metaphase I

Three somatic hybrids resulting from protoplast fusions of a diploid kanamycin-resistant line of tomato (Lycopersicon esculentum) and a dihaploid hygromycin-resistant transformant of a monohaploid potato (Solanum tuberosum) line were used for a cytogenetic study on chromosome pairing and meiotic recombination. Chromosome counts in root-tip meristem cells revealed two hypotetraploids with chromosome complements of 2n = 46 and one with 2n = 47. Electron microscope analyses of synaptonemal complex spreads of hypotonically burst protoplasts at mid prophase I showed abundant exchanges of pairing partners in multivalents involving as many as eight chromosomes. In the cells at late pachytene recombination nodules were found in multivalents on both sides of pairing partner exchanges, indicating recombination at both homologous and homoeologous sites. Light microscope observations of pollen mother cells at late diakinesis and metaphase I also revealed multivalents, though their occurrence in low frequencies betrays the reduction of multivalent number and complexity. Precocious separation of half bivalents at metaphase I and lagging of univalents at anaphase I were observed frequently. Bridges, which may result from an apparent inversion loop found in the synaptonemal complexes of a mid prophase I nucleus, were also quite common at anaphase I, though the expected accompanying fragments could be detected in only a few cells. Most striking were the high frequencies of first division restitution in preparations at metaphase II/anaphase II, giving rise to unreduced gametes. In spite of the expected high numbers of balanced haploid and diploid gametes, male fertility, as revealed by pollen staining, was found to be negligible.Key words: synaptonemal complex, recombination, chromosome pairing, somatic hybrid, Lycopersicon esculentum (+) Solanum tuberosum.

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.

Dilemma of genome relationship in the diploid species Thinopyrum bessarabicum and Thinopyrum elongatum (Triticeae: Poaceae)

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 944-946 ◽  
Author(s):  
Prem P. Jauhar
Keyword(s):  
Chromosome Pairing ◽  
Constitutive Heterochromatin ◽  
Diploid Species ◽  
Total Content ◽  
Ploidy Levels ◽  
5S Dna ◽  
Thinopyrum Bessarabicum ◽  
Thinopyrum Elongatum ◽  
Relationship Of ◽  
The Relationship

Evidence on the relationship of the J genome of diploid Thinopyrum bessarabicum and the E genome of diploid Thinopyrum elongatum (= Lophopyrum elongatum) is discussed. Low chromosome pairing between J and E at different ploidy levels, suppression of J–E pairing by the Ph1 pairing regulator that inhibits homoeologous pairing, complete sterility of the diploid hybrids (JE), karyotypic differentiation of the two genomes and differences in their biochemical organization as reflected in total content and distribution of constitutive heterochromatin, and marked differences in isozymes, 5S DNA, and rDNA indicate that J and E are distinct genomes. These genomes are homoeologous and not homologous. There is no justification for the merger of J and E genomes.Key words: chromosome pairing, Ph1 pairing regulator, C-banding, isozymes, 5S DNA, rDNA.

scholarly journals Polyploidy in Stokes Aster (Stokesia laevis)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1101A-1101
Author(s):  
Jessica Gaus ◽  
Dennis Werner ◽  
Shyamalrau Tallury
Keyword(s):  
Segregation Analysis ◽  
Karyotype Analysis ◽  
Flow Cytometric Analysis ◽  
Root Tip ◽  
Hybrid Progeny ◽  
Chromosome Counts ◽  
Segregation Behavior ◽  
Flow Cytometric ◽  
Triploid Block ◽  
Aberrant Segregation

Segregation analysis of two different F2 families of stokes aster created by hybridizing two blue-flowered cultivars [`Peaches Pick' (PE) and `Omega Skyrocket' (OSR)] with the yellow-flowered cultivar `Mary Gregory' (MG) gave disparate results. The F2 progeny of PE × MG segregated in the expected 3:1 (blue:yellow) ratio. In contrast, all 782 progeny from the MG × OSR F2 family were blue-flowered. Flow cytometric analysis of the parents and F1 hybrids was conducted to determine if ploidy differences existed among the parents, as such differences could account for aberrant segregation behavior in the MG × OSR F2 family. Peak ratios suggested that MG and PE were diploid, OSR was tetraploid, and F1 hybrids of MG × OSR were triploid. Chromosome counts from root tip squashes confirmed that MG and PE were diploid (2n= 2x= 14), OSR was tetraploid (2n= 4x= 28), and F1 hybrid progeny of MG × OSR were triploid (2n= 3x= 21). Karyotype analysis also confirmed these results. We propose that the lack of recovery of yellow-flowered progeny in the MG × OSR F2 family is due to differences in parental chromosome number. These results document the first report of polyploidy in stokes aster, and suggest the absence of a triploid block in this species.

THE SIGNIFICANCE OF MEIOTIC CHROMOSOME PAIRING IN TETRAPLOID (2n = 28) BROMUS PUMPELLIANUS SCRIBN. SSP. DICKSONII

1972 ◽  
Vol 14 (4) ◽  
pp. 763-771 ◽  
Author(s):  
K. C. Armstrong
Keyword(s):  
Chromosome Pairing ◽  
High Frequency ◽  
Chiasma Frequency ◽  
Karyotype Analysis ◽  
Meiotic Chromosome ◽  
Low Frequency ◽  
Meiotic Chromosome Pairing ◽  
Ring Bivalents ◽  
Bivalent Formation

Bivalent formation was predominant at meiosis in B. pumpellianus ssp. dicksonii. The average in 15 plants ranged from 11.38 to 13.77 bivalents per cell. The high chiasma frequency (23.41-26.74) was a reflection of the high frequency of ring bivalents (9.48-12.42). A low frequency of quadrivalents occurred (0.06-1.22). A karyotype of this species was presented from both a highly contracted and moderately contracted cell and the differences between these two were noted. Four satellites were found, two large and two minute. There were 3-5 submedian and 5-7 median chromosomes depending on the cell studied. In addition two subterminal chromosomes were present. The meiotic and karyotype analysis suggest a deviation from an autotetraploid behaviour, but the presence of quadrivalents and similarities between pairs in the karyotype suggested closely related genomes. Alternatively it was considered that the quadrivalents could be due to translocation heterozygotes. The implications of these results were discussed in relation to the reported meiotic events in the octoploids, B. inermis and B. pumpellianus.

scholarly journals The external mechanics of the chromosomes III-Meiosis in triploids

1936 ◽  
Vol 121 (823) ◽  
pp. 290-300 ◽  
Keyword(s):  
Sexual Reproduction ◽  
Chromosome Pairing ◽  
Natural Experiment ◽  
Diploid Species ◽  
Homologous Chromosomes ◽  
Normal Series ◽  
Mitosis And Meiosis ◽  
Meiosis I ◽  
Prophase Of Meiosis ◽  
The Way

Triploid organisms have three homologous chromosomes of each kind instead of the two of diploids. The regular mechanism of heredity fails in these circumstances. The triploid is incapable of breeding true by sexual reproduction. But the way in which it carries out the process of chromosome pairing and segregation is of great significance. The processes take place in normal series, but the relationships they establish are abnormal. A triploid thus provides a natural experiment, with the diploid of its own species as a control for one variable, and with triploids of different species as controls for others. In Tulipa and Hyacinthus I have made use of this experiment for inducing the principles of the external mechanics of chromosomes during the prophase of meiosis. I have inferred from them the relationships between the forces working in mitosis and meiosis. The triploid forms of various Fritillaria species make it possible to test the principles of metaphase mechanics induced from observations on structural hybrids and other polyploids (Darlington, 1932, b , and 1933, c ) as well as from the exceptional behaviour in the diploid species of Fritillaria already discussed.

scholarly journals Root tip chromosome karyotype analysis of hyacinth cultivars

2015 ◽  
Vol 14 (3) ◽  
pp. 10863-10876 ◽  
Author(s):  
F.R. Hu ◽  
H.H. Liu ◽  
F. Wang ◽  
R.L. Bao ◽  
G.X. Liu
Keyword(s):  
Karyotype Analysis ◽  
Root Tip ◽  
Chromosome Karyotype

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.

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