EFFECT OF RYE ON HOMOEOLOGOUS CHROMOSOME PAIRING IN WHEAT × RYE HYBRIDS

1977 ◽  
Vol 19 (3) ◽  
pp. 549-556 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Aestivum L ◽  
Homoeologous Chromosome ◽  
Wheat Genotype ◽  
Hybrid Plants ◽  
Homoeologous Chromosome Pairing ◽  
Secale Cereale L ◽  
Polygenic System

The number of chiasmata per cell at metaphase I was scored in eight haploid plants of Triticum aestivum L. emend. Thell. cv. 'Chinese Spring' and 100 hybrid plants of Chinese Spring × Secale cereale L. Mean chiasma frequency per cell ranged from 0.00 to 3.59 in the hybrids and from 0.17 to 0.35 in the haploids. Since the same wheat genotype was present in both the haploids and hybrids, it is concluded that some of the rye genotypes promoted homoeologous chromosome pairing. The absence of distinct segregation classes among the hybrids suggests that these genes constitute a polygenic system.

REDUCTION OF CHROMOSOME PAIRING BY A SPONTANEOUS MUTATION ON CHROMOSOMAL ARM 5DL OF TRITICUM AESTIVUM

1980 ◽  
Vol 22 (4) ◽  
pp. 569-575 ◽  
Author(s):  
Wanda S. Viegas ◽  
T. Mello-Sampayo ◽  
Moshe Feldman ◽  
Lydia Avivi
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Secale Cereale ◽  
Chinese Spring ◽  
Spontaneous Mutation ◽  
Triticum Aestivum L ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Promoter Allele

In a plant of Triticum aestivum L. em. Thell. cultivar Chinese Spring which was disomic for a mutant isochromosome of the long arm of chromosome 5D (di-isosomic 5DLM), partial chromosome asynapsis was detected at meiosis. Chromosome pairing in F1 hybrids from crosses of T. aestivum plants carrying the mutant isochromosome with Secale cereale, an intermediate pairing line of T. longissimum and with T. sharonensis disclosed that 5DLM carried a gene that reduced homoeologous chromosome pairing. This gene, designated Ph3 is less potent than its assumed homoeoallele on chromosomal arm 5BL, i.e., Ph1. The possibility of Ph1 being transferred from 5BL to 5DL through homoeologous chromosome pairing and recombination was discarded. Rather, it seems more likely that this allele resulted from a spontaneous mutation of the pairing-promoter allele known to be located on 5DL.

GENETIC VARIATION IN TRITICUM AFFECTING THE LEVEL OF CHROMOSOME PAIRING IN INTERGENERIC HYBRIDS

1970 ◽  
Vol 12 (2) ◽  
pp. 278-282 ◽  
Author(s):  
C. J. Driscoll ◽  
C. J. Quinn
Keyword(s):  
Triticum Aestivum ◽  
Genetic Variation ◽  
Natural Selection ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chiasma Frequency ◽  
Intergeneric Hybrids ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Aegilops Variabilis

Genetic differences which affect the extent of homoeologous chromosome pairing in intergeneric hybrids have been demonstrated between varieties of Triticum aestivum. Each of seven varieties of Triticum was crossed with the same strain of Aegilops variabilis. Significant differences in chiasma frequencies between varieties were found. Varieties Eureka, Gamut and Chinese Spring constitute one group with a relatively low chiasma frequency and varieties A. R. Falcon, Federation and Poso constitute a distinct second group with a relatively high chiasma frequency. The variety Bearded Yalta is intermediate to the two groups. Thus, this genetic variation appears to be common among varieties of Triticum. Presumably this variation does not become subject to natural selection as long as chromosome pairing in the parental varieties remains strictly homologous.

The inheritance of genetic variation in rye (Secale cereale) affecting homoeologous chromosome pairing in hybrids with bread wheat (Triticum aestivum)

1986 ◽  
Vol 28 (5) ◽  
pp. 844-851 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Triticum Aestivum ◽  
Genetic Variation ◽  
Chromosome Pairing ◽  
Secale Cereale ◽  
Chinese Spring ◽  
Continuous Distribution ◽  
Genetic System ◽  
Aegilops Speltoides ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing

Chiasmata frequencies ranging from 0.07 to 10.40 per cell were recorded in 125 hybrid plants derived from wheat × F1 rye crosses. These included 89 plants belonging to 28 families from the Triticum aestivum 'Chinese Spring' × Secale cereale F1 ('Petkus' × 'Prolific') cross and 36 plants belonging to 11 families from the 'Chinese Spring' × F1 ('Prolific' × 'Puma') cross. The data were analyzed to study the inheritance of genetic variation in rye affecting homoeologous chromosome pairing. The results were particularly interesting in the former case where segregation for major genes was evident. First, in this cross, a bimodal distribution was observed and second, chiasmata frequencies ranging from 6.11 to 10.40 per cell were observed in three families but without any hybrid falling in either the range of 3.0 to 6.0 or in the range of 6.11 to 9.82, showing discontinuous distribution. It was concluded that the genetic system in 'Petkus' differs from that in 'Prolific', and that genes both with major effects and minor effects may be present, the major effects possibly resulting from complementary gene action. In the second cross involving F1 rye plants derived from 'Prolific' × 'Puma', a smaller sample gave a continuous distribution with a single mode, the chiasmata frequency never exceeding 2.70 per cell. This could be due to a difference in genetic systems found in 'Puma' and 'Petkus' since 'Prolific' was a common parent in both crosses. The genetic variation in rye observed in the present study has been compared with that known in Aegilops speltoides and it was concluded that these may be of a similar nature.Key words: Triticum, Secale, pairing regulation, homoeologous pairing.

Promotion of homoeologous chromosome pairing in hybrids of Triticum aestivum × Aegilops variabilis

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 825-828 ◽  
Author(s):  
S. Farooq ◽  
N. Iqbal ◽  
T. M. Shah
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chiasma Frequency ◽  
Intergeneric Hybrids ◽  
Mutant Form ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Aegilops Variabilis

Intergeneric hybrids of Triticum aestivum variety Lu-26 and ph1b mutant of the cultivar Chinese Spring were produced with three accessions, A, B, and E, of Aegilops variabilis. Significant differences were found in the amount of homoeologous chromosome pairing at meiotic metaphase I. Hybrids between wheat variety Lu-26 and accessions A and B of Ae. variabilis showed very little pairing, as indicated by the chiasma frequency of 1.0 and 1.5 per cell, respectively. Hybrids between Lu-26 and accession E, on the other hand, showed significantly increased homoeologous pairing (mean chiasma frequency, 12.6/cell). The level of such pairing was essentially the same as that between the hybrids of ph1b 'Chinese Spring' × Ae. variabilis accessions A and B. However, when the ph1b mutant was hyridized with accession E, the level of chromosome pairing increased significantly (mean chiasma frequency, 17.52/cell). This is indicative of the presence of pairing promoter gene(s) in Ae. variabilis accession E, which are epistatic to the wheat Ph1 allele and positively interact with its mutant form to further increase the ph1b ceiling to homoeologous pairing in wheat.Key words: Triticum aestivum, ph1b mutant, Aegilops variabilis, intergeneric hybrids, homoeologous 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.

A bread wheat (Triticum aestivum) × cultivated barley (Hordeum vulgare) hybrid with homoeologous chromosome pairing

1986 ◽  
Vol 28 (5) ◽  
pp. 777-782 ◽  
Author(s):  
G. S. Sethi ◽  
R. A. Finch ◽  
T. E. Miller
Keyword(s):  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Nucleolus Organizer ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Partial Dominance ◽  
Nucleolus Organizer Regions ◽  
Homoeologous Chromosome Pairing

Triticum aestivum 'Chinese Spring' mutant ph1b lacking the major wheat homoeologous pairing prevention gene was pollinated with Hordeum vulgare line 'Tuleen 346,' a triple interchange homozygote with all chromosomes distinct from one another. Two wheat-like hybrids, one with 28 and one with 31 chromosomes, were produced. Homoeologous chromosome pairing occurred in the hybrids, but no evidence of interspecific chromosome pairing was observed. Both hybrids were sterile, but pollination of the 28-chromosome hybrid with 'Chinese Spring' pollen gave a few seeds. Within the F1 hybrids, chromosome numbers varied slightly, especially among pollen mother cells, and barley showed partial dominance of nucleolus organizer regions in somatic cells. The 31-chromosome hybrid was awned possibly indicating extra dosage of a homoeologous group-2 chromosome.Key words: wheat, barley, hybrid, homoeologous pairing.

CHROMOSOME DIFFERENTIATION IN POLYPLOID SPECIES OF ELYTRIGIA, WITH SPECIAL REFERENCE TO THE EVOLUTION OF DIPLOID-LIKE CHROMOSOME PAIRING IN POLYPLOID SPECIES

1981 ◽  
Vol 23 (2) ◽  
pp. 287-303 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Special Reference ◽  
Normal Level ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
Chromosome Differentiation

Triticum aestivum L. em Thell ditelosomics 7AL and 7DS and T. aestivum-Elytrigia elongata (Host) Holub (2n = 2x = 14) ditelosomic additions were crossed with "E. elongata 4x" (2n = 4x = 28), E. caespitosa (C. Koch) Nevski (2n = 4x = 28), and E. intermedia (Host) Nevski (2n = 6x = 42). The effect of each Elytrigia genotype on homoeologous (heterogenetic) chromosome pairing was assessed by comparing the pairing frequencies of T. aestivum cv. Chinese Spring telosomes 7AL and 7DS in the hybrids with the pairing frequency of telosome 7AL in haploid Chinese Spring. The genotype of "E. elongata 4x" had no effect on heterogenetic pairing in the hybrids. Although some genotypes of E. caespitosa and E. intermedia promoted heterogenetic pairing in the hybrids, others had no effect. Telosome VS of E. elongata interacted in a complementary fashion with the genotype of "E. elongata 4x," but not with the genotypes of Chinese Spring and E. caespitosa, and it promoted heterogenetic pairing. In hybrids in which the wheat diploidizing genes were active at the normal level, the E. elongata telosomes paired with chromosomes of "E. elongata 4x" in 5.8% to 24.6% of the cells, with chromosomes of E. caespitosa in 0.0% to 1.0% of the cells, and with chromosomes of E. intermedia in 0.0% to 2.8% of the cells. A model of chromosome differentiation is discussed and special attention is devoted to the origin of diploid-like pairing in polyploid species.

A WHEAT MUTATION CONDITIONING AN INTERMEDIATE LEVEL OF HOMOEOLOGOUS CHROMOSOME PAIRING

1982 ◽  
Vol 24 (6) ◽  
pp. 715-719 ◽  
Author(s):  
E. R. Sears
Keyword(s):  
Chromosome Pairing ◽  
Triticum Aestivum L ◽  
Terminal Segment ◽  
Intermediate Level ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
X Ray ◽  
Homoeologous Chromosome Pairing ◽  
Homozygous Line ◽  
A Minor

An X-ray-induced mutation in common wheat (Triticum aestivum L.), designated ph2, conditions an intermediate level of homoeologous chromosome pairing in hybrids with Triticum kotschyi var. variabilis. The number of chromosomes paired averaged 9.2 per sporocyte, compared with 2.0 in the control and 27.9 in the same hybrid involving ph1b, an apparent deficiency for Ph1 obtained in the same mutation experiment. The ph2 mutation is located on chromosome 3D and is believed to be a deficiency for a terminal segment of the short arm that includes the locus of Ph2, a minor suppressor of homoeologous pairing. Although no pairing of the ph2-carrying chromosome with telosome 3DS was observed, the mutation is clearly not a deficiency for the entire arm. It has little effect on pairing in wheat itself. Male transmission of the mutation is approximately normal, and fertility, while reduced, is sufficient for easy maintenance of the homozygous line.

Cytological and molecular characterization of a Triticum aestivum × Lophopyrum ponticum backcross derivative resistant to barley yellow dwarf

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 876-881 ◽  
Author(s):  
Gan-Yuan Zhong ◽  
Patrick E. Mcguire ◽  
Calvin O. Qualset ◽  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Barley Yellow Dwarf Virus ◽  
Virus Disease ◽  
Meiotic Chromosome ◽  
Yellow Dwarf ◽  
Homoeologous Chromosome ◽  
Barley Yellow Dwarf ◽  
Homoeologous Chromosome Pairing ◽  
Lophopyrum Ponticum

Barley yellow dwarf is the most damaging virus-caused disease in bread wheat (Triticum aestivum L.). A resistant line, SW335.1.2-13-11-1-5 (2n = 47), derived from a cross of T. aestivum × Lophopyrum ponticum was characterized by meiotic chromosome pairing, by in situ DNA hybridization and by expression of molecular markers to determine its chromosome constitution. All progeny of this line had three pairs of L. ponticum chromosomes from homoeologous chromosome groups 3, 5, and 6 and the 2n = 47 progeny had an additional L. ponticum monosome. The pairs from groups 3 and 6 were in the added state, while the group 5 pair was substituted for wheat chromosome 5D. Several wheat–wheat translocations with respect to the parental wheat genotype occurred in this line, presumably owing to the promotion of homoeologous chromosome pairing by L. ponticum chromosomes. It was hypothesized that homoeologous recombination results in homoeologous duplication–deletions in wheat chromosomes. An aberrant 3:1 disjunction creates the potential at each meiosis for replacement of these wheat chromosomes by homoeologous L. ponticum chromosomes. Wheat chromosomes 3A and 6A appeared to be in intermediate stages of this substitution process.Key words: wheat, wheatgrass, Lophopyrum, barley yellow dwarf virus, disease resistance, homoeologous chromosome recombination, homoeologous pairing, alien chromosome substitution.

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