scholarly journals Chromosome pairing in allohexaploid wheat var. Chinese Spring. Transformation of multivalents into bivalents, a mechanism for exclusive bivalent formation

1981 ◽  
Vol 46 (3) ◽  
pp. 129-173 ◽  
Author(s):  
Palle Hobolth
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Bivalent Formation ◽  
Allohexaploid Wheat

CHROMOSOME PAIRING IN POA ANNUA L.

1973 ◽  
Vol 15 (3) ◽  
pp. 549-551 ◽  
Author(s):  
W. M. Ellis ◽  
B. T. O. Lee ◽  
D. M. Calder
Keyword(s):  
Chromosome Pairing ◽  
Breeding System ◽  
Tetraploid Plant ◽  
Poa Annua ◽  
Diploid Population ◽  
Bivalent Formation

Cytological studies carried out on six tetraploid and one diploid population and a synthesized tetraploid plant have shown regular bivalent formation at meiosis. This regularity appears to be genetically controlled in this species. Plants from all the populations behave as diploids. The implications of this regular disomic chromosome pairing on recombination, variation and the breeding system of P. annua are considered.

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.

Suppression of homologous pairing between chromosomes of A and B genomes of 4x and 6x wheats by Hordeum californicum Covas and Stebbins

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 8-11
Author(s):  
H. S. Balyan ◽  
G. Fedak
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chiasma Frequency ◽  
Mother Cell ◽  
Triticum Turgidum ◽  
Regulatory Gene ◽  
Intergeneric Hybrids ◽  
Homologous Pairing ◽  
Meiotic Analysis ◽  
Hybrid Plants

Three hybrids of Triticum turgidum cv. Ma with Hordeum californicum × T. aestivum cv. Chinese Spring amphiploid were obtained at a frequency of 1.6% of the pollinated florets. Meiotic analysis of the hybrid plants revealed an average chiasma frequency per pollen mother cell ranging from 15.27 to 17.60. The lower than expected chromosome pairing in the hybrid plants was attributed to the suppression of pairing between homologous wheat chromosomes by pairing regulatory gene(s) in H. californicum.Key words: intergeneric hybrids, Hordeum californicum, Triticum turgidum, meiosis, chromosome pairing.

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.

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.

Segregation in the pollen of F2 rye (Secale cereale) plants for induction of homoeologous chromosome pairing in hybrids with wheat (Triticum aestivum)

Genome ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 888-891 ◽  
Author(s):  
P. K. Gupta ◽  
G. Fedak
Keyword(s):  
Spring Wheat ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chiasma Frequency ◽  
Significant Variation ◽  
Intergeneric Hybrids ◽  
Homoeologous Chromosome Pairing ◽  
Chinese Spring Wheat ◽  
Pollen Plants ◽  
Partial Amphiploids

An attempt was made to determine the inheritance of the rye genes which induce high chiasma frequency in hybrids with wheat and to study if the ability of rye to induce partial amphiploidy in hybrids with wheat was heritable. Five to eight F2 pollen plants were derived from seeds taken from each of three F1 plants that had given high chiasma frequency in hybrids with 'Chinese Spring' wheat in earlier studies. Similarly, six to seven F2 pollen plants were derived from each of three F1 plants that had given partial amphiploids in hybrids with 'Chinese Spring' wheat in earlier studies. Chiasma frequency was studied in 127 hybrids with 'Chinese Spring' wheat. In the present study, significant differences in chiasma frequency were observed (i) among the 38 families represented by 127 plants, and (ii) between two groups of three sets each, one known for inducing high pairing and the other known for inducing partial amphiploidy associated with low pairing in wheat × F1 rye plants. Significant variation was also observed between families within sets (each originated from one F1 rye plant) suggesting that F2 rye plants derived from the same F1 plants also differed genetically for inducing heterogenetic (homoeologous) pairing in wheat × rye hybrids. One of the six sets particularly showed significantly higher pairing with a mean of 2.13 per cell (individual hybrids gave a chiasma frequency as high as a mean of 6.07 per cell) as against a range of 0.96 to 1.18 in the remaining five sets, suggesting accumulation of genes in F2 rye plants for inducing pairing in wheat × rye hybrids. It is expected that by intermating the segregating rye plants, it should be possible to accumulate genes and eventually to isolate homozygous lines inducing high pairing in hybrids with wheat. Contrary to expectation, no partial amphiploids were obtained in a study of 127 wheat × F2 rye hybrids, although three of the six F1 rye plants had earlier given partial amphiploids in wheat × F1 rye hybrids. Key words: intergeneric hybrids, wheat, rye, genetic control, chromosome pairing.

scholarly journals Dmc1 is a candidate for temperature tolerance during wheat meiosis

2019 ◽  
Author(s):  
Tracie Draeger ◽  
Azahara Martin ◽  
Abdul Kader Alabdullah ◽  
Ali Pendle ◽  
María-Dolores Rey ◽  
...  
Keyword(s):  
High Temperatures ◽  
Chromosome Pairing ◽  
Meiotic Recombination ◽  
Low Temperatures ◽  
Chinese Spring ◽  
Deletion Mutant ◽  
Meiotic Chromosome ◽  
Wheat Chromosome ◽  
Chromosome Synapsis ◽  
Recombination Gene

AbstractWe have assessed the effects of high and low temperatures on meiotic chromosome synapsis and crossover formation in the hexaploid wheat (Triticum aestivum L.) variety ‘Chinese Spring’. At low temperatures, asynapsis and chromosome univalence have been observed before in Chinese Spring lines lacking the long arm of chromosome 5D (5DL), which led to the proposal that 5DL carries a gene (Ltp1) that stabilises wheat chromosome pairing at low temperatures. In the current study, Chinese Spring wild type and 5DL interstitial deletion mutant plants were exposed to low (13°C) or high (30°C) temperatures in controlled environment rooms during a period from premeiotic interphase to early meiosis I. A 5DL deletion mutant was identified whose meiotic chromosomes exhibit extremely high levels of asynapsis and chromosome univalence at metaphase I after seven days at 13°C. This suggests that the mutant, which we name ttmei1 (temperature tolerance in meiosis 1) has a deletion of a gene that, like Ltp1, normally stabilises chromosome pairing at low temperatures. Immunolocalisation of the meiotic proteins ASY1 and ZYP1 on ttmei1 mutants showed that low temperature results in a failure to complete synapsis at pachytene. After 24 hours at 30°C, ttmei1 mutants exhibited a reduced number of crossovers and increased univalence, but to a lesser extent than at 13°C. KASP genotyping revealed that ttmei1 has a 4 Mb deletion in 5DL. Of 41 genes within this deletion region, the strongest candidate for the stabilisation of chromosome pairing at low (and possibly high) temperatures is the meiotic recombination gene Dmc1.Key messageThe meiotic recombination gene Dmc1 on wheat chromosome 5D has been identified as a candidate for the maintenance of normal chromosome synapsis and crossover at low and possibly high temperatures.

Meiotic pairing in wheat–rye addition and substitution lines

1984 ◽  
Vol 26 (1) ◽  
pp. 25-33 ◽  
Author(s):  
J. Orellana ◽  
M. C. Cermeño ◽  
J. R. Lacadena
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Constitutive Heterochromatin ◽  
Banding Technique ◽  
Addition Line ◽  
Meiotic Pairing ◽  
Addition Lines ◽  
Substitution Lines ◽  
Homologous Chromosomes ◽  
Complex Process

Chromosome pairing was examined in wheat–rye addition and substitution lines using the C-banding technique. It was found that both rye and wheat chromosomes affect each other's homologous pairing. The strongest diminution of wheat pairing (measured as bound arms per cell) was produced by chromosome 5R of rye (7.5 and 7.2% in 'Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). The weakest diminution of wheat pairing was produced by chromosome 3R in the 'Chinese Spring' – 'Imperial' addition line (1.1%). The diminution of rye chromosome pairing produced by wheat chromosomes ranges from 6.9 to 48.4% ('Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). When put into a wheat background, the rye chromosomes suffer a worse fate than the wheat chromosomes. For example, chromosome 6R reduces the wheat complement pairing in the 'Holdfast' – 'King II' addition line by 3.8% but its own pairing is reduced by 41.4%. The decrease in pairing of both wheat and rye homologous chromosomes in addition and substitution lines is a complex process in which factors such as genes controlling meiotic pairing, constitutive heterochromatin, and cryptic wheat–rye interactions can play important roles.

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.

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