Arm homoeology of wheat and rye chromosomes

Genome ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 873-882 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
P. G. Goicoechea ◽  
R. Giraldez
Keyword(s):  
Key Words ◽  
Common Wheat ◽  
Chinese Spring ◽  
Structural Changes ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Wheat Evolution ◽  
C Banding ◽  
Chromosome Arm ◽  
Homoeology Relationships

Meiotic pairing was studied at metaphase I in three different cv. Chinese Spring × rye hybrid combinations (5B deficient, 3D deficient, and normal ABDR) to establish the arm homoeology of wheat and rye chromosomes. The majority of individual wheat chromosomes and their arms, as well as the arms of chromosomes 1R and 5R, were identified by means of C-banding. The results on pairing relationships support the genome reallocation of chromosomes 4A and 4B. The short arms of wheat chromosomes belonging to homoeologous groups 1, 3, 5, and 6 and of chromosome pairs 4A–4D and 7A–7D showed full pairing homoeology as well as the long arms of wheat chromosomes of groups 1, 3, 6, and 7 and of chromosome pairs 4A–4D and 5B–5D. Chromosomes 2A, 2B, and 2D were homoeologous, but the homoeologies of their arms were not identified. Reduced homoeologies of the 4BL arm to 7AS and 7DS, of the 5AL arm to 4AL and 4DL, and of the 7BS arm to 5BL and 5DL were identified. Arms 4BL, 5AL, and 7BS are involved in a double translocation that arose during the evolution of common wheat. The homoeology relationships of chromosome arm 4BS were not identified since this arm seldom paired. The homoeologous pairing pattern between wheat chromosomes was characterized by a remarkable predominance of A–D associations, altered only by structural changes in groups 4 and 5. Chromosome arm 1RL showed full pairing homoeology to 1AL, 1BL, and 1DL, while 5RL was homoeologous to 5AL and partially homoeologous to 4AL and 4DL. It is concluded that 5RL carries a translocated segment from 4RL. Key words: homoeologous pairing, translocations, wheat evolution, C-banding.

Cytogenetic identification of Triticum peregrinum chromosomes added to common wheat

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 272-276 ◽  
Author(s):  
B. Friebe ◽  
E. D. Badaeva ◽  
B. S. Gill ◽  
N. A. Tuleen
Keyword(s):  
Triticum Aestivum ◽  
Key Words ◽  
Common Wheat ◽  
Addition Lines ◽  
Karyotypic Analysis ◽  
Chromosome Addition ◽  
C Banding ◽  
Chromosome Addition Lines ◽  
Complete Set ◽  
Donor Species

C-banded karyotypes of a complete set of 14 Triticum peregrinum whole chromosome addition lines and 25 telosomic addition lines are reported. The added T. peregrinum chromosomes were not structurally rearranged compared with the corresponding chromosomes of the donor accession. Comprehensive karyotypic analysis confirmed Triticum umbellulatum as the donor species of the Uv genome and identified Triticum longissimum as the donor species of the Sv genome of T. peregrinum. Neither the Uv nor Sv genome chromosomes of the T. peregrinum accession showed large modifications when compared with the ancestral U and S1 genomes. Key words : Triticum aestivum, Triticum peregrinum, Triticum umbellulatum, Triticum longissimum, chromosome addition lines, C-banding.

Effect of Ph2 mutants promoting homoeologous pairing on spindle sensitivity to colchicine in common wheat

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 658-663
Author(s):  
Carla Ceoloni ◽  
Moshe Feldman
Keyword(s):  
Common Wheat ◽  
Suppressor Gene ◽  
Intergeneric Hybrids ◽  
Differential Sensitivity ◽  
Root Tip ◽  
Lower Sensitivity ◽  
Homoeologous Pairing ◽  
Wild Type ◽  
Cellular Target ◽  
Chromosome Arm

Two lines of common wheat cv. Chinese Spring carrying mutant alleles for the Ph2 homoeologous pairing-suppressor gene on chromosome arm 3DS promoting homoeologous pairing in wheat interspecific and intergeneric hybrids have been tested for their mitotic sensitivity to colchicine. Both the ph2a mutation, which corresponds to a fairly long deletion of 3DS, and ph2b, which is either an intragenic change or a very small deletion, as well as the ph2a/ph2b heteroallelic combination and the deficiency for the entire 3DS arm (ditelo 3DL), conditioned a significantly lower sensitivity to colchicine than that determined by the wild-type allele Ph2 (euploid and ditelo 3DS). Observation of both metaphase and anaphse root-tip cell populations, treated with various colchicine concentrations, provided similar results. The degree of spindle disruption in 2 × 10−4 M colchicine, as measured by the percentage of fully affected metaphases (C type), was significantly reduced in ph2 and Ph2− genotypes and, consequently, a larger proportion of cells could proceed toward anaphase and also had a regular segregation pattern at this stage. The differential sensitivity of ph2 genotypes to colchicine is in the opposite direction to that previously found for ph1 genotypes, lacking the homoeologous pairing suppressor on chromosome arm 5BL. The ph2 mutation, while promoting homoeologous pairing as ph1 does, decreases spindle sensitivity to colchicine with respect to the wild-type (ph2) allele rather than increasing it, as ph1 does. The observed alteration of spindle sensitivity to colchicine that mutants for structurally unrelated but functionally related genes (Ph1 and Ph2) condition is interpreted as a highly probable coincidence in their cellular target. It is assumed therefore that these loci affect the equilibrium between tubulin and microtubules. Through this effect they presumably determine chromosome positioning in somatic and premeiotic stages, leading to different pairing patterns at meiosis. Key words: Triticum aestivum, tubulin, pairing suppressors, somatic association.

Identification of chromosome segments controlling the synthesis of peroxidases in wheat seeds and in transfer lines with Agropyron elongatum

1978 ◽  
Vol 56 (8) ◽  
pp. 1091-1094 ◽  
Author(s):  
K. Kobrehel
Keyword(s):  
Common Wheat ◽  
Gel Electrophoresis ◽  
Chinese Spring ◽  
Electrophoretic Analysis ◽  
Agropyron Elongatum ◽  
Transfer Lines ◽  
Chromosome Arm ◽  
Chromosome Segments ◽  
Wheat Seeds

The genes coding the synthesis of the three major cathodic isoperoxidases a, c, and d in common wheat cv. Chinese Spring, as determined by polyacrylamide slab gel electrophoresis, are located on the chromosome arms 7DS, 4BL, and 7AS, respectively. Transfer lines with Agropyron elongatum can be detected by electrophoretic analysis of peroxidases if the chromosome arm 7AgS is involved in these transfers. Results have also shown a homology between the chromosome 7D of common wheat and the chromosome 7Ag of Agropyron elongatum.

Image analysis of C-banded chromosomes and pairing regionalization in wheat

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 1062-1067 ◽  
Author(s):  
Angeles Bernardo ◽  
Martin Montero ◽  
Angeles Cuadrado ◽  
Nicolás Jouve
Keyword(s):  
Image Analysis ◽  
Chinese Spring ◽  
Genetic Factors ◽  
Triticum Turgidum ◽  
Chromosome Region ◽  
Chromosome Length ◽  
Physical Parameters ◽  
Meiotic Pairing ◽  
C Banding ◽  
Mutant Lines

C-banding and image analysis are used to characterize nine somatic chromosomes of wheat and to quantify a series of physical parameters (arm length, heterochromatic band intensity and position) in tetraploid Triticum turgidum and hexaploid T. aestivum wheat. The arm-by-arm meiotic association of the chromosomes at first meiotic metaphase is evaluated with respect to these parameters and genetic pairing regulators. The effect of the genetic factors is analyzed comparatively in homozygous lines or both normal and mutant lines (Ph1/Ph1, ph1a/ph1a, ph1b/ph1b, and ph1c/ph1c) and in aneuploids (ditelo-5BL and nulli-5B–tetra-5D). The pairing values were progressively reduced as follows: 'Chinese Spring' Ph1/Ph1 > 'Chinese Spring' dt-5BL > 'Chinese Spring' ph1a/ph1a > 'Chinese Spring' nulli-5B–tetra-5D > 'Chinese Spring' ph1b/ph1b > 'Cappelli' ph1c/ph1c. The results indicate that although a different contribution to overall pairing exists for each specific chromosome region, the differences in the genetic systems regulating pairing from line to line indiscriminately affected chiasma levels and did not lead to specific deviations in any line. The results seem to show that maintenance of chiasmata at first metaphase of meiosis depends on chromosome length and correlation is strong for the chance of double chiasmata. Moreover, there are indications that some C-bands, particularly in intercalary positions in chromosome arms 4AL, 2BL, 5BS, and 7BL, increase the frequency of chiasma at first metaphase. The pairing intensity in each specific chromosomal segment may be the product of an integrated action of chromosome length, the presence or absence of heterochromatin, and genetic factors.Key words: image analysis, heterochromatin, Triticum, C-banding, meiotic pairing.

EFFECT OF THE REMOVAL OF GENES PROMOTING HOMOEOLOGOUS CHROMOSOME PAIRING ON CHROMOSOME PAIRING IN TRITICUM AESTIVUM × TRITICUM URARTU AMPHIPLOIDS

1978 ◽  
Vol 20 (4) ◽  
pp. 539-544 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Triticum Urartu ◽  
The Poor ◽  
Homoeologous Chromosome Pairing ◽  
Chromosome Arm ◽  
Specific Strain

Chromosome pairing in Triticum aestivum cv. Chinese Spring × T. urartu hybrids lacking chromosome arm 5AS or 5BS was shown to be lower than in similar hybrids involving euploid Chinese Spring. Amphiploids were produced from crosses of Chinese Spring, ditelosomic 5AL, and ditelosomic 5BL with a specific strain of T. urartu. The absence of asynapsis in the amphiploids lacking chromosome arm 5AS or 5BS provides evidence that the poor chromosome pairing observed in the corresponding F1 hybrids was due to suppression of homoeologous pairing and not to general asynapsis. This conclusion is supported by the finding that heterogenetic chromosome pairing, as evidenced by the frequency of multivalents, was lower in the ditelo 5BL × T. urartu amphiploids than in the amphiploids from the cross Chinese Spring × T. urartu.

The analysis of meiosis of the B genome in common wheat

1985 ◽  
Vol 27 (1) ◽  
pp. 17-22 ◽  
Author(s):  
N. Jouve ◽  
J. M. Gonzalez ◽  
A. Fominaya ◽  
E. Ferrer
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Triticum Aestivum L ◽  
Genome Chromosome ◽  
Meiotic Analysis ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
B Genome ◽  
Whole Genomes ◽  
Chromosome Arm

Two intervarietal hybrids of common wheat, Triticum aestivum L., are meiotically analyzed using the C-banding staining method. The C-banding pattern of nine meiotic chromosomes (4A, 7A, and the seven of the B genome) permitted their unequivocal recognition at first metaphase plates. The pairing frequency of each B-genome chromosome arm was scored. Data on the pairing frequency of the arms, separately considered, are applied to calculate expected pairing of whole chromosomes and whole genomes. The application of mathematical models to predict the genome pairing using either equal or different frequencies per chromosome arm is discussed.Key words: meiotic analysis, Triticum aestivum L., C-banding.

Combining mutations for the two homoeologous pairing suppressor genes Ph1 and Ph2 in common wheat and in hybrids with alien Triticeae

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 377-386 ◽  
Author(s):  
Carla Ceoloni ◽  
Paolo Donini
Keyword(s):  
Common Wheat ◽  
Interspecific Hybrids ◽  
Double Mutant ◽  
Homoeologous Pairing ◽  
Suppressor Genes ◽  
Plant Variation ◽  
Significant Difference ◽  
Chromosome Arm ◽  
Aegilops Variabilis ◽  
Pairing Behaviour

Two lines of common wheat cv. Chinese Spring, carrying simultaneous mutations for the two major homoeologous pairing wheat suppressor genes Ph1 and Ph2 have been developed and their pairing behaviour compared with that of the ph1b mutant of the same cultivar. Besides carrying the ph1b mutation, the first double mutant line lacked the chromosome arm pair 3DS, containing Ph2, whereas the second had a euploid constitution and carried the ph1b allele on 3DS. Hybrids of Aegilops variabilis and Secale cereale with mono-5B (ph1b) and 3D/3DL plants have also been obtained, where the 3D versus 3DL presence marked the two pairing alternatives (ph1b only and ph1b + Ph2−, respectively). In the wheat × Ae. variabilis hybrids, an 8% increase in total chromosome pairing, almost entirely ascribable to an increment of multivalent associations, was observed in the 2n = 34 + t plants with respect to their 2n = 35 sibs. The number of bivalents showed no significant difference, but a tendency towards a decrease, which was significant for the rod types, was exhibited by the Ph2− plants. A weaker but similar effect was observed in wheat itself. The different mutants, in fact, showed a similar percentage of paired chromosomes but varied in their pairing pattern. A significant reduction in the number of bivalents, owing to a decrease of the rings, only partly compensated for by an increase of the rods, was observed in the double mutants. They also exhibited an increase in the multivalent fraction, which was significant for the most complex associations. In both common wheat and its hybrids with Ae. variabilis the addition of a ph2 mutation thus seems to reinforce the ph1b effect in promoting homoeologous pairing. On the other hand, such an effect was not noticed in the wheat × S. cereale hybrids. However, possible quantitative differences could have been masked by the considerable plant-to-plant variation and potential differences in relative incidence of wheat–wheat versus wheat–rye associations were undetectable in the Feulgen-stained materials analyzed.Key words: common wheat, interspecific hybrids, homoeologous pairing, Ph mutations.

Meiotic duration in wheat genotypes with or without homoeologous meiotic chromosome pairing

1974 ◽  
Vol 187 (1087) ◽  
pp. 191-207 ◽  
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Meiotic Chromosome ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Meiotic Chromosome Pairing ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
The Cross ◽  
Pairing Behaviour

In order to investigate the possible relation between meiotic time and meiotic chromosome pairing behaviour, meiosis was timed in various forms of wheat and wheat hybrids. First, meiosis was timed in ten Triticum aestivum (var. Chinese Spring) genotypes with different chromosome constitutions which differed widely in the meiotic pairing behaviour. Secondly, in order to escape from the disadvantage of aneuploid material, meiosis was also timed in plants which differed in the extent of homoeologous pairing because of the activities of different alleles at one or two loci. For this experiment use was made of F 1 -hybrids from the cross T. aestivum x Aegilops mutica which, although they all have 28 chromosomes, differ widely in the amount of homoeologous pairing. Thirdly, meiosis was also timed in 28-chromosome and 29-chromosome plants derived from the cross between rye (Secale cereale) x 43-chromosome T. aestivum containing a single Ae. mutica addition chromosome known to carry genes which greatly affect the level of homoeologous pairing in wheat. Although the 28-chromosome plants display very little pairing (chiasma frequency per cell (c. f.) = 0.5) while 29-chromosome plants display a much higher amount of pairing (c. f. = 7.8) no difference in meiotic time was detected between them. Similarly, the duration of meiosis was not significantly different between the three types of F 1 -hybrids between T. aestivum x Ae. mutica which had chiasma frequencies of 14.3, 7.4 and 0.9. Thus, these results agree in showing that there was no correlation between the duration of meiosis and the amount of homoeologous chromosome pairing. The results obtained for genotypes of Chinese Spring also provided no evidence to support the notion that there is a relation between the level of chromosome pairing and the duration of the pairing process. Consequently some doubt must be cast upon the idea that the time available for pairing is limiting to the pairing process. It was shown that individual wheat chromosomes in Chinese Spring differed in their effects on meiotic duration. For instance, the absence of chromosome 7B has no detectable effect on meiotic duration. The absence of chromosome 5B in two genotypes resulted in an increase in meiotic time from that found in euploid plants (24 h) to that found in tetraploid wheat species (about 30 h). By using plants ditelosomic for chromosome 5B L it was shown that most, if not all, of the genetic effects of chromosome 5B on meiotic time are determined by the short arm.

Effect of different doses of group-2 chromosomes on homoeologous pairing in intergeneric wheat hybrids

1986 ◽  
Vol 28 (2) ◽  
pp. 240-246 ◽  
Author(s):  
C. Ceoloni ◽  
I. Strauss ◽  
M. Feldman
Keyword(s):  
Common Wheat ◽  
Chinese Spring ◽  
Intergeneric Hybrid ◽  
Homoeologous Pairing ◽  
Aegilops Variabilis ◽  
Group 2 ◽  
Wheat Hybrids ◽  
A Minor ◽  
Homoeologous Chromosomes ◽  
Different Doses

While an extra dose of chromosome 2A of common wheat, previously reported to carry a pairing promoter on its short arm, did not increase pairing between homoeologous chromosomes in F1 hybrids between common wheat cv. Chinese Spring (CS) and Aegilops variabilis, two doses of chromosome 2D or 2B caused a significant increase in homoeologous pairing. Evidently, chromosomes 2D and 2B carry a pairing promoter(s). Studies of F1 hybrids between aneuploids of CS, either deficient for chromosome 2D or having it in an extra dose, and Ae. variabilis, Ae. longissima, and Secale cereale supported the finding that this chromosome carries a pairing promoter. Using ditelosomic lines, the promoter was found to be located on the short arm of 2D (2DS). It was deduced that the promoter of 2B is also located on the homoeologous short arm, i.e., on 2BS. Evidence was obtained that the long arm of 2D may carry a suppressor(s) of pairing. Thus, the short arm of 2A, 2D, and 2B carries a pairing promoter(s), while the long arm of 2D and possibly of 2A and 2B carry a minor suppressor(s). The promoters are more potent than the suppressors and the overall effect of group-2 chromosomes is pairing promotion.Key words: wheat, homoeologous pairing, pairing promoter, pairing suppressor, intergeneric hybrid, meiosis.

Different genetic systems in rye affecting homoeologous pairing in wheat – rye combinations

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 793-796 ◽  
Author(s):  
M. C. Cuadrado ◽  
C. Romero
Keyword(s):  
Triticum Aestivum ◽  
Secale Cereale ◽  
Chinese Spring ◽  
Genetic System ◽  
The Other ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Major Genes ◽  
Genetic Systems ◽  
Polygenic System

The present study analyzed meiotic pairing in wheat – rye hybrids obtained by crossing of Triticum aestivum cv. Chinese Spring with allogamous ryes, two cultivars of Secale cereale ('Don Enrique' and 'Selectión') and Secale cereale ssp. segetale. The results indicate that each rye type has different behaviour on hybrid meiotic pairing because they contain distinct genetic systems affecting meiotic pairing. In the case of 'Don Enrique' and 'Selección,' a polygenic system could be present, but not identical in both cultivars. On the other hand, Secale cereale ssp. segetale contained genes that strongly affect the genetic system controlling homoeologous pairing in wheat.Key words: homoeologous pairing, wheat – rye hybrids, polygenic system, major genes.

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