Metaphase I pairing of deficient chromosomes and genetic mapping of deficiency breakpoints in common wheat

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 553-560 ◽  
Author(s):  
C. A. Curtis ◽  
A. J. Lukaszewski ◽  
M. Chrzastek
Keyword(s):  
Triticum Aestivum ◽  
Genetic Mapping ◽  
Chromosome Pairing ◽  
Triticum Aestivum L ◽  
Genetic Distances ◽  
Homologous Chromosomes ◽  
Transmission Rates ◽  
Chromosome 5B ◽  
Pairing Initiation ◽  
Metaphase I

Metaphase I pairing of deficient chromosomes was analyzed in a set of 'Chinese Spring' (CS) wheat (Triticum aestivum L. em. Thell.) plants with varying lengths of deficiencies in the long arm of chromosome 4A (6, 8, 11, 17, 23, 34, 36, 39, and 50% missing), the long arm of chromosome 5B (49% missing), and the long arm of chromosome 2B (33% missing). Pairing in homologous chromosomes between deficient and complete arms was greatly reduced even by small differences in arm length. In deficiency homozygotes and in an isochromosome derived from a deficient 4AL arm, pairing of the two deficient arms was high and approached that of two complete arms. In plants where deficient and complete arms competed for pairing partners, pairing was exclusively between arms of the same length. These results suggest that in wheat, pairing initiation sites are distributed throughout at least the distal halves of the arms and that the alignment of telomeres may be critical for pairing success. Genetic mapping of the deficiency breakpoints was confounded by misdivision of unpaired chromosomes and abnormal transmission rates. Genetic distances between centromeres and breakpoints appeared to be proportional to metaphase I pairing frequencies.Key words: bread wheat, deficiency, chromosome pairing competition, mapping, telomere, pairing initiation.

GENETIC REGULATION OF HETEROGENETIC CHROMOSOME PAIRING IN POLYPLOID SPECIES OF THE GENUS TRITICUM sensu lato

1982 ◽  
Vol 24 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Patrick E. McGuire ◽  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Genetic Regulation ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
D Genome ◽  
Chromosome 5B ◽  
A Genome

Polyploid species of Triticum sensu lato were crossed with Triticum aestivum L. em. Thell. cv. Chinese Spring monotelodisomics or ditelosomics that were monosomic for chromosome 5B. Progeny from these crosses were either euploid, nullisomic for 5B, monotelosomic for a given Chinese Spring chromosome, or nullisomic for 5B and monotelosomic simultaneously. The Chinese Spring telosome in the hybrids permitted the evaluation of autosyndesis of chromosomes of the tested species. In addition, several Chinese Spring eu- and aneuhaploids were produced. Genotypes of T. cylindricum Ces., T. juvenale Thell., T. triunciale (L.) Raspail, T. ovatum (L.) Raspail, T. columnare (Zhuk.) Morris et Sears, T. triaristatum (Willd.) Godr. et Gren., and T. rectum (Zhuk.) comb. nov. were all shown to have suppressive effects on heterogenetic pairing in hybrids lacking 5B or 3AS, whereas T. kotschyi (Boiss.) Bowden had no effect. It was concluded that diploid-like meiosis in these species is due to genetic regulation. A number of these genotypes promoted heterogenetic pairing in the presence of 5B. A model is presented to explain this dichotomous behavior of the tested genotypes. Monotelosomic-3AL haploids had a greater amount of pairing than did euhaploid Chinese Spring, which substantiated the presence of a pairing suppressor(s) on the 3AS arm. Evidence is presented that shows that T. juvenale does not have a genome homologous with the D genome of T. aestivum.

METAPHASE I PAIRING FREQUENCIES OF INDIVIDUAL AGROPYRON ELONGATUM CHROMOSOME ARMS WITH TRITICUM CHROMOSOMES

1979 ◽  
Vol 21 (2) ◽  
pp. 243-254 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chromosome Complement ◽  
Triticum Aestivum L ◽  
Diploid Hybrid ◽  
Agropyron Elongatum ◽  
D Genome ◽  
Telocentric Chromosomes ◽  
Metaphase I

Ten telocentric chromosomes of diploid Agropyron elongatum (Host.) P.B. (2n = 14) were added to the chromosome complement of Triticum aestivum L. emend. Thell. The ditelosomic additions were crossed with Triticum speltoides (Tausch) Gren. ex Richter, and in the tetraploid hybrids the pairing frequencies of the telosomes were determined, expressed as percent of PMC's in which a telosome paired at metaphase I. All Agropyron telosomes paired with Triticum chromosomes. The pairing frequencies ranged from 4.4% to 41.2% of the PMC's, it is concluded that none of the ten Agropyron chromosome arms has a homologous partner among the four Triticum genomes involved. The pairing frequencies did not correlate with the lengths of the telosomes. Pairing of the Agropyron telosomes in these tetraploid hybrids approximated the chromosome pairing that occurred in a diploid hybrid T. tauschii (Coss.) Schmal. (the donor of the D genome of T. aestivum) × A. elongatum.

Mapping of a chromosome pairing gene and 5S rRNA genes in Triticum aestivum L. by a spontaneous deletion in chromosome arm 5Bp

1986 ◽  
Vol 28 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Rama S. Kota ◽  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Aestivum L ◽  
5S Rrna ◽  
Rrna Genes ◽  
C Banding ◽  
Aegilops Longissima ◽  
Chromosome 5B ◽  
5S Rrna Genes

A deletion in the p arm of chromosome 5B of Triticum aestivum L. cv. Chinese Spring was identified by C-banding during the production of disomic substitutions of 6B of Aegilops longissima Schweinf. et Muschl. for chromosome 5B of cv. Chinese Spring. The deletion was terminal with a breakpoint just proximal to the interstitial C-band. The degree of metaphase I chromosome pairing in plants homozygous for the deletion indicated that the chromosome pairing promoting gene known to be in the p arm of chromosome 5B is located in the deleted portion of that arm. Additionally, all of the 5S ribosomal RNA genes known to exist on arm 5Bp were mapped to this deleted portion.Key words: C-banding, 5S rRNA genes, Triticum, Aegilops chromosome aberration.

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.

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.

Cytogenetic studies of progenies from crosses between 'Centurk' wheat and its doubled haploids derived from anther culture

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 622-628 ◽  
Author(s):  
Sawsan S. Youssef ◽  
R. Morris ◽  
P. S. Baenziger ◽  
C. M. Papa
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Doubled Haploid ◽  
Structural Changes ◽  
Meiotic Chromosome ◽  
Doubled Haploids ◽  
Triticum Aestivum L ◽  
Root Tips ◽  
Doubled Haploid Lines ◽  
A Minor

Karyotype stability, which is essential when using wheat (Triticum aestivum L.) doubled haploids in a breeding program, was evaluated in 14 anther-derived doubled-haploid lines after at least three generations of selfing, by crossing them as females with the parent cultivar 'Centurk' and doing cytological studies on the progenies. There were no deviations from the hexaploid chromosome number (2n = 42) in root tips. Meiotic chromosome pairing was as stable as that in the control ('Centurk' × 'Centurk') in most progenies. Chromosomal structural changes and (or) behavioral deviations were detected at the metaphase I, anaphase I, telophase I, and quartet stages of meiosis in a minor proportion of the cells. The frequencies of multivalents, lagging bivalents and univalents, bridges, and micronuclei were higher in some progenies than in the control. Chromosomal fragments were infrequent. The ranges in percentages of normal cells were 72.4–90.0 at anaphase I, 76.4–92.6 at telophase I, and 82.6–93.2 at quartet stages in the doubled-haploid progenies, compared with 95–100, 92–100, and 94–96, respectively, in the control. On the basis of these results, the doubled-haploid lines should produce enough normal gametes to provide adequate seed supplies when they are used as parents in wheat cultivar and population improvement.Key words: Triticum aestivum, chromosome pairing, chromosome aberrations, gametoclonal variation.

Identification and genetic mapping of PmAF7DS a powdery mildew resistance gene in bread wheat (Triticum aestivum L.)

2016 ◽  
Vol 129 (6) ◽  
pp. 1127-1137 ◽  
Author(s):  
I. N. Bheema Lingeswara Reddy ◽  
K. Chandrasekhar ◽  
Y. Zewdu ◽  
A. Dinoor ◽  
B. Keller ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Genetic Mapping ◽  
Resistance Gene ◽  
Bread Wheat ◽  
Powdery Mildew Resistance ◽  
Triticum Aestivum L ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance

Development and genetic mapping of sequence-tagged microsatellites (STMs) in bread wheat (Triticum aestivum L.)

2006 ◽  
Vol 113 (7) ◽  
pp. 1271-1281 ◽  
Author(s):  
M. J. Hayden ◽  
P. Stephenson ◽  
A. M. Logojan ◽  
D. Khatkar ◽  
C. Rogers ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Genetic Mapping ◽  
Bread Wheat ◽  
Triticum Aestivum L

Genetic mapping of three alleles at the Pm3 locus conferring powdery mildew resistance in common wheat (Triticum aestivum L.)

Genome ◽  
2004 ◽  
Vol 47 (6) ◽  
pp. 1130-1136 ◽  
Author(s):  
Xiu-Qiang Huang ◽  
Sai L.K Hsam ◽  
Volker Mohler ◽  
Marion S Röder ◽  
Friedrich J Zeller
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Genetic Mapping ◽  
Microsatellite Markers ◽  
Microsatellite Marker ◽  
Powdery Mildew Resistance ◽  
Triticum Aestivum L ◽  
Mildew Resistance ◽  
Marker Loci ◽  
Mapping Populations

A set of differential isolates of Blumeria graminis f.sp. tritici was used to identify 10 alleles at the Pm3 locus on the short arm of chromosome 1A. Three F3 populations were used to map Pm3h in Abessi, Pm3i in line N324, and Pm3j alleles in GUS 122 relative to microsatellite markers. In total, 13 marker loci were mapped on chromosome 1AS and 1 marker on 1AL. The order of marker loci in the 3 mapping populations is consistent with previously published maps. All 3 alleles were mapped in the distal region of chromosome 1AS. The present study indicated that microsatellite markers are an ideal marker system for comparative mapping of alleles at the same gene locus in different mapping populations. The linkage distances of the closest microsatellite marker, Xgwm905–1A, to Pm3h, Pm3i, and Pm3j were 3.7 cM, 7.2 cM, and 1.2 cM, respectively. The microsatellite marker Xgwm905–1A cannot be used to distinguish between Pm3 alleles. The development of specific markers for individual Pm3 alleles is discussed on the basis of the recently cloned Pm3b allele.Key words: genetic mapping, marker-assisted selection, microsatellite markers, Pm3 locus, powdery mildew resistance, Triticum aestivum.

Interlocked bivalents in reconstructed metaphase I cells of bread wheat

1985 ◽  
Vol 75 (1) ◽  
pp. 85-92
Author(s):  
J.S. Heslop-Harrison ◽  
M.D. Bennett
Keyword(s):  
Triticum Aestivum ◽  
Light Microscopy ◽  
Bread Wheat ◽  
Chromosome Pairing ◽  
Light Microscope ◽  
Serial Sections ◽  
Ring Bivalents ◽  
Mother Cells ◽  
I Cells ◽  
Metaphase I

Complete reconstructions of all the bivalents were made from electron micrographs of serial sections through six pollen mother cells at metaphase I of meiosis in Triticum aestivum (hexaploid bread wheat). At least two of these metaphases contained interlocked pairs of bivalents. In one, two ring bivalents were interlocked, while in another a rod bivalent ran through the centre of a ring bivalent. Two other groups of bivalents were too closely appressed to allow separation into individual bivalents and may have contained interlocks. Meiosis in other anthers of the same plants examined by light microscopy was considered normal. The frequency of interlocking found was much higher than reported from light-microscope spreads. Not all interlocks in metaphase I cells need adversely affect meiosis, but knowledge of their regularity and form may facilitate understanding the processes of chromosome pairing.

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