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.

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.

CYTOLOGY AND FERTILITY OF PENTAPLOID WHEAT HYBRIDS WITH INDUCED PAIRING BETWEEN HOMOEOLOGOUS CHROMOSOMES

1982 ◽  
Vol 24 (4) ◽  
pp. 397-408 ◽  
Author(s):  
U. Kushnir ◽  
G. M. Halloran
Keyword(s):  
Chromosome Pairing ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Triticum Aestivum L ◽  
The Other ◽  
Homoeologous Chromosome ◽  
D Genome ◽  
Homoeologous Chromosome Pairing ◽  
Wheat Hybrids ◽  
Homoeologous Chromosomes

Two mutants, each promoting homoeologous chromosome pairing in hexaploid wheat (Triticum × aestivum L. emend gr. aestivum), in the cultivar Chinese Spring, ph1b at the Ph locus on chromosome 5BL and the other, ph2, on chromosome 3DS, were compared for their influence on chromosome pairing and fertility in pentaploid hybrids with Triticum turgidum L. emend var. dicoccoides (Korn. in litt. in Schweinf.). The mutants induced increased multivalent frequency over the normal pentaploid. Lower univalent frequencies in the ph2-pentaploid, compared with the normal pentaploid, indicated that D-genome chromosomes of the former were substantially involved in homoeologous pairing. Certain differences in other meiotic processes and fertility among the pentaploids may reflect differences in the activity of the pairing genes. There appeared to be a higher level of univalent elimination in pollen and egg cells in the ph2-, compared with the ph1b-pentaploid. Tetrad formation was close to normal in the ph2- pentaploid but exhibited high levels of abnormality (monads, dyads, triads and apolar tetrads) in the ph1b-pentaploid. Fertility levels in crosses of the pentaploids with hexaploid wheat, while low, were much lower for the ph1b-, compared with the ph2-pentaploid.

GENETIC SUPPRESSION OF HOMOEOLOGOUS CHROMOSOME PAIRING IN HEXAPLOID WHEAT

1972 ◽  
Vol 14 (1) ◽  
pp. 39-42 ◽  
Author(s):  
C. J. Driscoll
Keyword(s):  
Chromosome Pairing ◽  
Hexaploid Wheat ◽  
Homoeologous Pairing ◽  
Homoeologous Group ◽  
Homoeologous Chromosome ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
Genetic Complexity ◽  
Genetic Suppression ◽  
Group 3

Greater genetic complexity has been revealed for the control of bivalency in hexaploid wheat. A suppressor of homoeologous pairing has been detected on chromosome 3A. Thus, there are two suppressors in homoeologous group 3. The 3A suppressor may be homoeoallelic to either the suppressor on 3Dβ or the promoter, detected in this study, on 3Dα. Individually these two suppressors are less effective than the suppressor on the long arm of chromosome 5B; however, their combined effect is yet to be studied. This greater complexity suggests that hexaploid wheat may not be too dissimilar to other polyploids as regards genetic control of bivalency. The mode of action of these suppressors appears to be consistent with a heteromultimeric hypothesis.

Comparison of homoeologous chromosome pairing between hybrids of wheat genotypes Chinese Spring ph1b and Kaixian-luohanmai with rye

Genome ◽  
2011 ◽  
Vol 54 (12) ◽  
pp. 959-964 ◽  
Author(s):  
Ming Hao ◽  
Jiangtao Luo ◽  
Min Yang ◽  
Lianquan Zhang ◽  
Zehong Yan ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Genomic In Situ Hybridization ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Wheat Genotypes ◽  
Phenotypic Differences ◽  
Homoeologous Chromosome Pairing

The ph-like genes in the Chinese common wheat landrace Kaixian-luohanmai (KL) induce homoeologous pairing in hybrids with alien species. In the present study, meiotic phenotypic differences on homoeologous chromosome pairing at metaphase I between hybrids of wheat genotypes Chinese Spring ph1b (CSph1b) and KL with rye were studied by genomic in situ hybridization (GISH). The frequency of wheat–wheat associations was higher in CSph1b × rye than in KL × rye. However, frequencies of wheat–rye and rye–rye associations were higher in KL × rye than in CSph1b × rye. These differences may be the result of different mechanisms of control between the ph-like gene(s) controlling homoeologous chromosome pairing in KL and CSph1b. Wheat–wheat associations were much more frequent than wheat–rye pairing in both hybriods. This may be caused by lower overall affinity, or homoeology, between wheat and rye chromosomes than between wheat chromosomes.

Assessment of chromosome associations in haploids and their parental accessions in Hordeum

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 204-210 ◽  
Author(s):  
R. von Bothmer ◽  
N. C. Subrahmanyam
Keyword(s):  
Genetic Variation ◽  
Chromosome Pairing ◽  
Diploid Species ◽  
Meiotic Behaviour ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Homologous Pairing ◽  
Homoeologous Chromosome Pairing ◽  
Chromosome Associations

Meiotic pairing was studied in the following species and their haploid derivatives: Hordeum cordobense 2x, H. marinum 2x and 4x, H. secalinum 4x, H. capense 4x, H. jubatum 4x, H. brachyantherum 4x and 6x, H. lechleri 6x, and H. procerum 6x. The study revealed (i) homologous pairing in diploid species and very little nonhomologous associations in their mono-haploids; (ii) the alloploid nature of the polyploid taxa; (iii) a certain degree of homoeologous pairing in polyhaploids despite the diploid-like meiotic behaviour of the polyploids; (iv) genetic variation in the suppression of homoeologous chromosome pairing in different Hordeum species.Key words: Hordeum, meiotic pairing, haploids.

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.

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.

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.

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