Chromosome pairing in hybrids of ph1b mutant wheat with rye

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 639-646 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
R. Giraldez ◽  
P. G. Goicoechea
Keyword(s):  
Common Wheat ◽  
Chromosome Pairing ◽  
Chromosome Structure ◽  
Preferential Pairing ◽  
C Banding ◽  
Homoeologous Chromosomes ◽  
Metaphase I

Metaphase I pairing was studied in five ph1b mutant wheat × rye hybrids to verify the presence of translocations between homoeologous chromosomes in ph1b mutant wheat and to establish the pairing homoeology between wheat and rye chromosomes. Three 5B-deficient ABDR hybrids with standard chromosome structure were used as controls. Chromosomes 1R and 5R of rye and most wheat chromosomes, as well as their arms, were identified by means of C-banding. The presence of 5BS in ph1b hybrids raised the overall pairing level. The pattern of pairing between wheat chromosomes in ph1b hybrids, as in 5B-deficient hybrids, was characterized by the occurrence of preferential pairing between chromosomes of the A and D genomes in most homoeologous groups. The existence of a double translocation involving 4BL, 5AL, and 7BS in common wheat was confirmed. Deviation from the standard pairing pattern suggested the existence of a translocation involving 1BL and 1DL in one ph1b ABDR plant and another translocation involving 3AL and 3DL in three other ph1b hybrids. In ph1b hybrids, wheat – rye pairing was relatively frequent for 1RL, 5RL, and an arm of a metacentric rye chromosome, probably 2R, that is homoeologous to 2BL, and the homoeologous arms of 2A and 2D. The existence of a translocation involving 5RL and 4RL in rye was confirmed.Key words: homoeologous, homologous, 5B-deficient, translocations, C-banding.

FERTILITY AND MEIOTIC BEHAVIOUR IN TETRAPLOID BARLEY

1975 ◽  
Vol 17 (1) ◽  
pp. 121-123 ◽  
Author(s):  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Behaviour ◽  
Preferential Pairing ◽  
Subsequent Fertility ◽  
Structural Differences ◽  
Hordeum Leporinum ◽  
Metaphase I

Chromosome pairing at metaphase I and distribution at anaphase I were examined in 3 autotetraploid and 3 amphidiploid parents and their F1 hybrids and related to spike fertility of the respective plants. Structural differences translocated from the Hordeum leporinum chromosomes to H. vulgare did not significantly enhance preferential pairing and subsequent fertility in the latter as anticipated. Quadrivalent formation was not related but regular disjunction at anaphase I was related to spike fertility.

Meiotic pairing in haploids and amphidiploids of spontaneous versus synthetic origin in rape, Brassica napus L.

1986 ◽  
Vol 28 (3) ◽  
pp. 330-334 ◽  
Author(s):  
T. Attia ◽  
G. Röbbelen
Keyword(s):  
Brassica Napus ◽  
Chromosome Number ◽  
Chromosome Pairing ◽  
Structural Modification ◽  
Meiotic Pairing ◽  
Chromosome Behaviour ◽  
Preferential Pairing ◽  
Brassica Napus L ◽  
Bivalent Formation ◽  
Homoeologous Chromosomes

Newly resynthesized AC amphihaploids, which were characterized by high meiotic pairing and multivalent formulation, after doubling of their chromosome number showed preferential pairing and bivalent formation in the resynthesized amphidiploid Brassica napus (AACC). However, univalents as well as multivalents were also formed indicating that their chromosome behaviour was not fully diploidized. Stabilization of chromosome pairing in newly resynthesized amphidiploids can be achieved through genetic control or structural modification of the homoeologous chromosomes. A comparison of the meiotic behaviour of spontaneous haploids of natural rapeseed with that of the newly synthesized AC amphihaploids provides some evidence that both processes may be involved in the regulation of chromosome pairing in Brassica.Key words: Brassica, amphihaploid, amphidiploid, meiosis, univalents, multivalents.

Genome constitutions of Thinopyrum curvifolium, T. scirpeum, T. distichum, and T. junceum (Triticeae: Gramineae)

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 641-651 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Banding Pattern ◽  
Triploid Hybrid ◽  
Target Species ◽  
Banding Patterns ◽  
C Banding ◽  
Geographical Separation ◽  
Basic Genome ◽  
Karyotype Analyses ◽  
Metaphase I

The objective of this study is to elucidate genome constitutions of Thinopyrum curvifolium (Lange) D.R. Dewey, T. scirpeum (K. Presl) D.R. Dewey, T. distichum (Thunb.) A. Löve, and T. junceum (L.) A. Löve. Hybrids of T. sartorii (Boiss. &Heidr.) A. Löve with T. scirpeum and T. junceum, as well as the hybrid between T. curvifolium and Pseudoroegneria geniculata ssp. scythica (Nevski) A. Löve, were made and chromosome pairing at metaphase I was studied. The karyotype analyses of mitotic cells stained by aceto-orcein were conducted for both hybrids and the four target species. The Giemsa C-banding following acetocarmine staining was carried out for the above species and the triploid hybrid T. curvifolium × T. bessarabicum (Savul &Rayss) A. Löve. Meiotic data indicate that all target species have two sets of the basic genome J, but they behave like true allopolyploids because of bivalentization. Karyotypes of T. curvifolium and its triploid hybrid with T. bessarabicum indicate that T. curvifolium contains two different versions of the Jb genome, designated as Jb3 and Jb4, rather than two Je genomes as previously believed. Thinopyrum scirpeum and T. elongatum (4x) have similar karyotypes. Both are segmental allotetraploids carrying two forms of the Je genome. Their genome formulae are Je2 Je3 and Je1 Je3, respectively. Thinopyrum distichum has a karyotype similar to T. junceiforme, which has the Jb2 Je2 genome formula. However, the two species differ in C-banding patterns, reflecting their geographical separation. Thinopyrum junceum is a hexaploid with two pairs of Jb2 genomes and one pair of the Je2 genome, and it has a C-banding pattern similar to that of T. junceiforme, which has one pair each of the Jb2 and Je2 genomes.Key words: genome, meiosis, karyotype, C-banding, Triticeae, Thinopyrum.

Chromosome pairing and aneuploidy in tetraploid triticale. II. Unstabilized karyotypes

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 562-569 ◽  
Author(s):  
Adam J. Lukaszewski ◽  
Barbara Apolinarska ◽  
J. Perry Gustafson ◽  
K.-D. Krolow
Keyword(s):  
Key Words ◽  
Chromosome Pairing ◽  
Homoeologous Pairing ◽  
Polyploid Species ◽  
C Banding ◽  
Group 4 ◽  
Genome Recombination ◽  
Segregation Ratios ◽  
Homoeologous Chromosomes

In the progeny of tetraploid triticale plants that segregated for either one, two, or three pairs of homoeologous wheat chromosomes, plants were selected that had 13 pairs of homologues and 1 pair of presumed wheat homoeologues. Segregation ratios of "homoeologues" were close to 1:2:1 except for group 4, where no 4B homozygotes were recovered. Aneuploid frequency among 190 progeny of the segregating plants was 4.74%. C-banding at meiosis showed that "homoeologues" paired with frequencies ranging from 0.1 to 1.74 paired arms per chromosome. The only exception was the 4A–4B pair, which did not synapse. It was concluded that the high pairing frequencies between "homoeologous" chromosomes were due to translocations that had accumulated during line development. With few exceptions, translocations could not be detected by C-banding. The results demonstrate that genome recombination in polyploid species may occur at two levels simultaneously: by segregation of complete chromosomes and by translocations between homoeologues. Key words: C-banding, homoeologous pairing, translocations.

Meiotic pairing of specific chromosome arms in triploid rye

1984 ◽  
Vol 26 (6) ◽  
pp. 717-722 ◽  
Author(s):  
Elena Benavente ◽  
Juan Orellana
Keyword(s):  
Meiotic Pairing ◽  
Preferential Pairing ◽  
Specific Chromosome ◽  
C Banding ◽  
Expected Values ◽  
Metaphase I

From the meiotic configurations at metaphase I of triploid plants it is possible to estimate the frequency of trivalent pairing (f) at pachytene. Although the meiotic pairing frequencies for specific chromosome arms (detected by C-banding) could not always be estimated owing to restrictions of the model, a good fit between observed and expected values was generally found. One case of preferential pairing between heteromorphic chromosome arms was observed. Heterochromatin apparently does not play any role in determining pairing preferences.Key words: triploid rye, C-heterochromatin, meiotic pairing.

Pairing affinities of the B- and G-genome chromosomes of polyploid wheats with those of Aegilops speltoides

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 814-819 ◽  
Author(s):  
S Rodríguez ◽  
B Maestra ◽  
E Perera ◽  
M Díez ◽  
T Naranjo
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Triticum Turgidum ◽  
Aegilops Speltoides ◽  
Meiotic Pairing ◽  
Triticum Timopheevii ◽  
C Banding ◽  
Tetraploid Wheats ◽  
B Genome ◽  
Metaphase I

Chromosome pairing at metaphase I was studied in different interspecific hybrids involving Aegilops speltoides (SS) and polyploid wheats Triticum timopheevii (AtAtGG), T. turgidum (AABB), and T. aestivum (AABBDD) to study the relationships between the S, G, and B genomes. Individual chromosomes and their arms were identified by means of C-banding. Pairing between chromosomes of the G and S genomes in T. timopheevii × Ae. speltoides (AtGS) hybrids reached a frequency much higher than pairing between chromosomes of the B and S genomes in T. turgidum × Ae. speltoides (ABS) hybrids and T. aestivum × Ae. speltoides (ABDS) hybrids, and pairing between B- and G-genome chromosomes in T. turgidum × T. timopheevii (AAtBG) hybrids or T. aestivum × T. timopheevii (AAtBGD) hybrids. These results support a higher degree of closeness of the G and S genomes to each other than to the B genome. Such relationships are consistent with independent origins of tetraploid wheats T. turgidum and T. timopheevii and with a more recent formation of the timopheevi lineage.Key words: Triticum turgidum, Triticum timopheevii, Aegilops speltoides, meiotic pairing, evolution, C-banding.

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.

The influence of fixation on the morphology of mitotic chromosomes

1986 ◽  
Vol 28 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Axel J. J. Dietrich
Keyword(s):  
Acetic Acid ◽  
Chemical Composition ◽  
Strong Influence ◽  
Chromosome Structure ◽  
Human Lymphocytes ◽  
Chromosome Morphology ◽  
Mitotic Chromosomes ◽  
Specific Chemical ◽  
C Banding ◽  
Sister Chromatids

It is well known that there is a strong influence of fixation, i.e., acetic methanol versus formaldehyde, on the chromosome morphology at stages of the first meiotic division. In this study the influence of both these types of fixation on the morphology of mitotic chromosomes was examined in human lymphocytes. After methanol – acetic acid (3:1) fixation, the chromosomes show the "classical" condensed shape in which it is not always possible to recognize the two sister chromatids. These chromosomes are accessible to the conventional G-, R-, and C-banding techniques. After formaldehyde fixation at a relatively high pH, the chromosomes are thinner and longer (two to six times) when compared with chromosomes following methanol – acetic acid fixation. They show a scaffold-like morphology, sometimes with a halo of thin material around it. In all cases the two sister chromatids could be recognized. This chromosome structure could be easily stained with silver, Giemsa, 4,6-diamino-2-phenyl-indole (DAPI), and fluorescein isocyanate isomere 1 (FITC). The results obtained following these stainings gave no indication to any specific chemical composition of a probable central scaffold. The scaffold-like structures were not accessible to G-, R-, or C-banding techniques. The only effect observed following these banding techniques was the disappearance of the halo of thin material around the central scaffold-like structure.Key words: chromosome structure, fixation influence, human lymphocytes.

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