Reinvestigation of the S genome in Triticum kotschyi

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 521-524 ◽  
Author(s):  
Yang Yen ◽  
Gordon Kimber
Keyword(s):  
Chromosome Pairing ◽  
Reciprocal Translocation ◽  
Triploid Hybrid ◽  
First Report ◽  
Tetraploid Hybrid ◽  
Donor Species

Hybrids of Triticum kotschyi with induced autotetraploids of Triticum longissimum, Triticum speltoides, and Triticum bicorne and diploid T. speltoides were obtained. This is the first report of successful hybridization between T. kotschyi and T. bicorne. Optimizing meiotic data showed that the tetraploid hybrid involving T. longissimum (4x) fit the 3:1 model best with an x-value of 1.000, while those involving T. speltoides (4x) and T. bicorne (4x) fit the 2:2 and 2:1:1 models best with an x-value of 0.744 and 0.989, respectively. The triploid hybrid of T. kotschyi × T. speltoides fit the 3:0 model best with an x-value of 0.500. A reciprocal translocation was observed between T. kotschyi and T. speltoides. It is suggested that T. longissimum is the possible donor species of the S genome to T. kotschyi and that this S genome has remained essentially unchanged since its incorporation. This and other evidence suggest that T. kotschyi likely originated from the hybridization of T. longissimum × T. umbellulatum.Key words: hybrid, meiosis, chromosome pairing, autotetraploid, phylogenesis.

Chromosome pairing in triploid and tetraploid hybrids in Elytrigia (Triticeae; Poaceae)

1984 ◽  
Vol 26 (5) ◽  
pp. 519-522 ◽  
Author(s):  
Patrick E. McGuire
Keyword(s):  
Chromosome Pairing ◽  
Genome Analysis ◽  
Triploid Hybrid ◽  
Pollen Mother Cells ◽  
Tetraploid Hybrid ◽  
A Genome ◽  
Mother Cells ◽  
Metaphase I

Mean chromosome pairing of 5.14I + 1.28II (rod) + 3.86II (ring) + 1.47III + 0.11IV (open) + 0.11V was observed in pollen mother cells at metaphase I in the triploid hybrid Elytrigia scirpea (K. Presl) Holub, 2n = 4x = 28 × E. bessarabica (Savul. et Rayss) Dubrovik, 2n = 4x = 14. Mean chromosome pairing of 3.71I + 2.29II (rod) + 1.82II (ring) + 2.64III + 0.29IV (open) was observed in the triploid hybrid E. curvifolia (Lange) Holub, 2n = 4x = 28 × E. bessarabica. Mean chromosome pairing of 3.00I + 0.93II (rod) + 1.57II (ring) + 1.36III + 1.79IV (open) + 1.I4IV (closed) + 0.79V was observed in the tetraploid hybrid E. junceiformis Löve et Löve, 2n = 4x = 28 × E. curvifolia. The first hybrid provides the first evidence by genome analysis that E. bessarabica possesses a genome (designated Eb) which is closely related to the genomes of E. scirpea (ES and ESC) and hence to the E genome of E. elongata (Host) Nevski, 2n = 2x = 14. The second and third hybrids provide the first evidence that the two genomes of E. curvifolia (designated EC and ECU) are related to the Eb genome of E. bessarabica and thus to the E genome of E. elongata.Key words: Elytrigia, homoeology, Triticum, phylogeny, triploid, tetraploid.

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.

Genome analysis of Thinopyrum junceiforme and T. sartorii

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 758-764 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Chromosome Banding ◽  
Triploid Hybrid ◽  
Meiotic Pairing ◽  
Organizational Changes ◽  
Banding Patterns ◽  
Small Satellites ◽  
Basic Genome ◽  
Dna Organization ◽  
Karyotype Analyses

Genome constitutions of Thinopyrum junceiforme (A. Löve and D. Löve) A. Löve (2n = 4x = 28) and T. sartorii (Boiss. &Heldr.) A. Löve (2n = 4x = 28) were determined by studying (i) meiotic pairing patterns in hybrids involving the two species and other pertinent hybrids; (ii) mitotic chromosome karyotypes based on length, arm ratio, and satellites; and (iii) C-banding patterns. New hybrids synthesized and reported are T. sartorii × T. bessarabicum (2n = 3x = 21), T. sartorii × (T. bessarabicum × T. elongatum) amphidiploid (2n = 4x = 28), and the reciprocal of the latter. Mean meiotic pairing in the triploid hybrid and the two tetraploid hybrids were 3.83 I + 3.92 II + 3.11 III, 0.931 + 7.46 II + 0.62 III + 2.44 IV + 0.07 V + 0.03 VI, and 3.41 I + 9.39 II + 0.74 III + 0.88 IV, respectively. Based on the chromosome pairing data, it can be concluded that T. junceiforme and T. sartorii have two versions (Jb and Je) of the J genome and behave like true allotetraploids owing to bivalentization. Karyotype analyses of the species and their hybrids with T. bessarabicum revealed minor structural differentiations of the genomes in the two species. Thinopyrum sartorii has one genome basically unchanged from the Jb genome of T. bessarabicum while another is a modified Je genome of T. elongatum. One genome of T. junceiforme is modified from Jb and the other is modified from Je. There are two pairs of large and one pair of small satellites in T. sartorii, but there are only one pair of each in T. junceiforme. Thinopyrum junceiforme is rich and T. sartorii is poor in interstitial C-bands for both sets of genomes. Thinopyrum sartorii has larger terminal C-bands on the Jb genome chromosomes than those of T. junceiforme. These organizational changes of chromosomes could not be detected by studying chromosome pairing alone. However, this study demonstrates that meiotic pairing is the first criterion for determining basic genome symbols. Other techniques, such as those involving chromosome banding, isozymes, and DNA probes, may then be used to detect differences in chromosome (or DNA) organization and gene expression.Key words: genome, hybrid, meiosis, karyotype, chromosome banding, speciation.

Can epigenetic control explain pronounced within-plant heterogeneity of meiosis in a translocation trisome of Secale L.?

Genome ◽  
2012 ◽  
Vol 55 (4) ◽  
pp. 257-264 ◽  
Author(s):  
J. Sybenga
Keyword(s):  
Chromosome Pairing ◽  
Sexual Differentiation ◽  
Reciprocal Translocation ◽  
Meiotic Metaphase ◽  
Homology Search ◽  
Crossing Over ◽  
Somatic Variation ◽  
Cell Lineages ◽  
Secale Cereale L ◽  
Plant Grown

Meiotic metaphase I configuration frequencies were determined in different tillers of genetically related plants of rye ( Secale cereale L.) heterozygous for reciprocal translocation T248W (between chromosome arms 1RS and 6RS) and with an additional (telocentric) arm 1RS. Seventeen different configurations could be recognized, grouped into three categories. Very different configuration frequencies were found not only between sister plants from the same parents but also between tillers of the same plant grown under identical conditions (climate chambers at 15 °C and 20 °C). The heterogeneity reflects variation in chromosome pairing and crossing over, and is variable and unpredictable. Anthers within florets were homogeneous. Between tiller heterogeneity is insufficient to explain differences between sister plants. It is ascribed to random somatic variation in the conditions of the chromatin which, at meiosis, govern chromosome pairing. During sexual differentiation, these conditions are fixed and subsequent cell lineages have the same pairing and crossing over characteristics. As homology search is an activity of DNA, this control of pairing and crossing over, consistent over long cell lineages, may be considered to be epigenetic even when no realistic suggestions concerning its character can be given.

Interspecific hybrids between a transgenic rapeseed (Brassica napus) and related species: cytogenetical characterization and detection of the transgene

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1099-1106 ◽  
Author(s):  
M. C. Kerlan ◽  
A. M. Chevre ◽  
F. Eber
Keyword(s):  
Chromosome Pairing ◽  
Related Species ◽  
Interspecific Hybrids ◽  
Plant Production ◽  
Triploid Hybrid ◽  
Bar Gene ◽  
Meiotic Behavior ◽  
Gene Dispersal ◽  
Gene Characterization ◽  
Transgenic Rapeseed

In interspecific hybrids produced between a transgenic rapeseed, an allotetraploid species, resistant to herbicide, phosphinotricin, and five diploid related species, the risk for gene introgression in weed genomes was explored through cytogenetic and bar gene characterizations. Among the 75 hybrids studied, most had the expected triploid structure, with the exception of B. napus – B. oleracea amphidiploid plants and one B. napus – S. arvensis amphidiploid plant. In triploid hybrid plants, the reciprocal hybrids did not exhibit any difference in their meiotic behavior. The comparison of the percentage of chromosome pairing in the hybrids with that of haploid rapeseed permit to conclude that allosyndesis between AC genomes and related species genomes took place. This possibility of recombination was confirmed by the presence of multivalent associations in all the interspecific hybrids. Nevertheless, in B. napus – B. adpressa hybrids a control of chromosome pairing seemed to exist. The possibility of amphidiploid plant production directly obtained in the F1 generation increased the risk of gene dispersal. The B. napus – B. oleracea amphidiploid plant presented a meiotic behavior more regular than that of the B. napus – S. arvensis amphidiploid plant. Concerning the herbicide bar gene characterization, the presence of the gene detected by DNA amplification was correlated with herbicide resistance, except for two plants. Different hypotheses were proposed to explain these results. A classification of the diploid species was established regarding their gene dispersal risk based on the rate of allosyndesis between chromosomes of AC genomes of rapeseed and the genomes of the related species.Key words: Brassicaceae, transgenic rapeseed, risk assessment, interspecific hybrids, chromosome pairing, bar gene characterization.

Chromosome pairing in triploid hybrids and amphidiploids involving Lolium and diploid Festuca species

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 472-477 ◽  
Author(s):  
W. G. Morgan
Keyword(s):  
Chromosome Pairing ◽  
Phylogenetic Relationships ◽  
Meiotic Behaviour ◽  
Triploid Hybrid ◽  
Chromosome Size ◽  
Chromosome Homology ◽  
Precise Identification

Chromosome homology between Lolium and Festuca complements are assessed in triploid and tetraploid hybrids with variable doses of the different diploid genomes. In general, the chromosome pairing observed in the triploid hybrid gave a better prediction of the meiotic behaviour of the tetraploid amphidiploids than that found in the diploid hybrids. Differences in chromosome size between the complements allowed the precise identification of the chromosomes in chiasmate associations and there was evidence that most chromosome pairing was between homologues. In the triploid hybrids, associations between nonhomologous chromosomes were recorded. The results, based on chromosome pairing data, are briefly discussed in relation to genome homologies and phylogenetic relationships in the Lolium-Festuca complex.Key words: Lolium, Festuca, chromosome pairing, nonhomologous, triploid hybrids, amphidiploids.

scholarly journals Genome Size and Ploidy of Phlox paniculata and Related Germplasm in Subsections Paniculatae and Phlox

2015 ◽  
Vol 140 (5) ◽  
pp. 436-448 ◽  
Author(s):  
Peter J. Zale ◽  
Pablo Jourdan
Keyword(s):  
Genome Size ◽  
Ornamental Plants ◽  
Size Variation ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Triploid Hybrid ◽  
Chromosome Counts ◽  
Ploidy Levels ◽  
First Report ◽  
Phlox Paniculata

Phlox is an important genus of herbaceous ornamental plants previously targeted for germplasm development, characterization, and enhancement by the U.S. Department of Agriculture, National Plant Germplasm System. Among Phlox in cultivation, Phlox paniculata is the most widely grown and intensively bred species, but little is known about variation in genome size and ploidy of this species or of related taxa that may be used for germplasm enhancement. The objective of this study was to assess cytotype variation in a diverse collection of cultivars and wild germplasm of P. paniculata (subsection Paniculatae) and of related taxa in subsections Paniculatae and Phlox. The collection included 138 accessions from seven species and two interspecific hybrids. Flow cytometry was used to estimate holoploid (2C) genome sizes and to infer ploidy levels. Chromosome counts were made to calibrate ploidy with genome size for a subset of taxa. Most cultivars were diploid (2n = 2x = 14) and had mean genome sizes that did not vary between subsections Paniculatae (14.33 pg) and Phlox (14.23 pg) although size variation was greater among cultivars within subsection Phlox. Triploid cultivars of P. paniculata, with a mean genome size of 21.36 pg and mitotic chromosome counts of 2n = 3x = 21, were identified. Such triploids suggests previous interploid hybridization within this taxon. Five tetraploid (2n = 4x = 28) cultivars were found in subsection Phlox; all were selections of P. glaberrima ssp. triflora, and had a mean genome size of 25.44 pg; chromosome counts in one of these confirmed they were tetraploid. The putative hybrid Phlox Suffruticosa Group ‘Miss Lingard’ showed an intermediate genome size of 21.21 pg supporting a triploid, hybrid origin of this taxon. Mean 2C genome sizes among wild-collected accessions were similar to values reported for cultivars (Paniculatae = 14.59 pg, Phlox = 14.23 pg), but taxa in subsection Phlox exhibited greater variation that included two tetraploids identified among wild-collected accessions; one, of P. pulchra, had a mean genome size of 26.17 pg, representing the first report of polyploidy in the taxon. This is the first report on genome size for the majority of species in the study. Although genome size could not be used to differentiate taxa in subsections Paniculatae and Phlox, the data provide further insights into cytotype variation of Phlox germplasm useful for plant breeders and systematists.

Further hybrids involving the perennial autotetraploid oat Avena macrostachya

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 273-275 ◽  
Author(s):  
J. M. Leggett
Keyword(s):  
Chromosome Pairing ◽  
Triploid Hybrid ◽  
Genome Species ◽  
A Genome ◽  
C Genome

Chromosome pairing in the triploid hybrid Avena damascena × A. macrostachya is very similar to the chromosome pairing observed in previously reported triploid hybrids involving the A genome diploid taxa A. atlantica and A. prostrata, indicating that little more than residual homology remains between these A genome diploids and either of the genomes of A. macrostachya. The chromosome pairing in the hybrid between A. macrostachya and the C genome diploid A. ventricosa is similar to that observed in the previously reported hybrid A. eriantha × A. macrostachya. In both these hybrids, the frequency of trivalents is greater than that observed in hybrids involving the A genome species and A. macrostachya, which is indicative of closer homology of A. macrostachya to the C genome diploids than the A genome diploids.Key words: Avena, hybrids, interspecific chromosome pairing, phylogeny.

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.

scholarly journals Meiotic Behavior and RAPD Segregation in a Tetraploid Hybrid (Vaccinium darrowi × V. corymbosum) Suggests Genomic Divergence in Blueberry

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 808D-808 ◽  
Author(s):  
Nicholi Vorsa ◽  
Richard Novy
Keyword(s):  
Chromosome Pairing ◽  
Backcross Progeny ◽  
Tetraploid Hybrid ◽  
Ring Bivalents ◽  
Genome Homology ◽  
Pairing Model ◽  
Vaccinium Darrowi ◽  
Mother Cells ◽  
Wild Blueberry ◽  
Interspecific Recombination

Vaccinium darrowi (D) is a wild blueberry species with low chilling requirements for budbreak, and heat and drought tolerance. Breeding efforts to incorporate these desirable traits into cultivated blueberry (V. corymbosum) (C) would be facilitated with a better understanding of the genomic homology between the two species. An interspecific tetraploid hybrid (CCDD, 2n=4x=48) was used to evaluate genome homology and interspecific recombination. Pollen mother cells examined at diakinesis and early metaphase I exhibited an average of 4.6 chain bivalents, 11.4 ring bivalents, 1.0 chain quadrivalent, and 3.0 ring quadrivalents. This data most closely fits a chromosome pairing model in which there is a greater pairing affinity between homologues than homoeologues. An analysis of the inheritance of 14 RAPD markers unique to V. darrowi in 72 backcross progeny of the V. darrowi–corymbosum hybrid also supported the pairing model: Seven of the 14 markers deviated significantly from tetrasomic inheritance ratios, expected if chromosome pairing was totally random. On the basis of the cytogenetic and RAPD analyses, the genomes of V. darrowi and V. corymbosum are divergent from one another, with preferential pairing within genomes. This outcome suggests there may be difficulty in breaking undesirable linkages when introgressing desirable traits from V. darrowi to V. corymbosum.

Sign in / Sign up

Export Citation Format

Share Document