The effect of different doses of Ph1 on chromosome pairing in hybrids between tetraploid Agropyron elongatum and common wheat

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 974-977 ◽  
Author(s):  
A. Charpentier ◽  
M. Feldman ◽  
Y. Cauderon

Chromosome pairing at first meiotic metaphase was studied in F1 hybrids between tetraploid cytotypes of Agropyron elongatum and common wheat lines of the cultivar Chinese Spring, carrying zero, one, and two doses of Ph1. The bivalentization gene system of A. elongatum could not compensate for the absence of Ph1: hybrids deficient for this gene exhibited pairing between the Agropyron E1 and E2 chromosomes, between the wheat A, B, and D chromosomes, and between the Agropyron and the wheat chromosomes. In hybrids with one or two doses of Ph1, pairing was restricted to the Agropyron E1 and E2 chromosomes. It was concluded that E1 and E2 are distant homologues, thus further supporting the autoploidy nature of tetraploid A. elongatum. The genomic relationships in other polyploid species of the genus Agropyron is discussed in the light of this evidence.Key words: chromosome pairing, Triticum, common wheat, Agropyron.

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 978-983 ◽  
Author(s):  
A. Charpentier ◽  
M. Feldman ◽  
Y. Cauderon

Chromosome pairing at first meiotic metaphase was studied in hybrids between the common wheat cultivar Chinese Spring (CS) and an induced autotetraploid line derived from diploid Agropyron elongatum. The latter was found to carry genes for homoeologous pairing. To determine the chromosomal location of these and other genes that control pairing, disomic addition lines of A. elongatum in the cv. Chinese Spring were crossed with tetraploid cytotypes of A. elongatum, and pairing was then compared in the resulting hybrids and in hybrids between cv. Chinese Spring and tetraploid A. elongatum. The elongatum chromosomes were classified into those that suppress (6E), promote (5E, 3E, and possibly 1E), or have no effect on pairing (4E). The effect of chromosomes 2E and 7E was not studied. Chromosomes 5E and 3E differed in their effect on the degree and pattern of chromosome pairing. These findings are compared with the available data on the control of pairing in A. elongatum and in other Triticinae species.Key words: chromosome pairing, pairing promoter, Triticum, common wheat, Agropyron.


1981 ◽  
Vol 23 (2) ◽  
pp. 287-303 ◽  
Author(s):  
J. Dvořák

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.


1983 ◽  
Vol 25 (3) ◽  
pp. 278-282
Author(s):  
Julian B. Thomas ◽  
P. J. Kaltsikes ◽  
S. Shigenaga

Chromosome 1B in 'Rosner' and chromosome 6B in line 125 both reduced the frequency with which chromosomes were paired at first meiotic metaphase of hexaploid triticale. On the other hand, chromosome 6B in 'Rosner' and chromosomes 1B and 6B in line 110 had no such effect. The 1B pairing suppressor in 'Rosner' was located on the short arm of the chromosome (1Bs). Between 10 and 30 °C, pairing frequency was quite stable in 'Rosner' triticale in comparison with common wheat, although the level was consistently lower in the triticale. Some reduction of pairing frequency was noted at 10 °C in 'Rosner'. This effect of low temperature did not interact with 1B dosage to cause a disproportionate decrease in pairing frequency when plants with high 1B dosage were grown at 10 °C.


1982 ◽  
Vol 24 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Patrick E. McGuire ◽  
Jan Dvořák

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.


1976 ◽  
Vol 18 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Jan Dvořák

Chromosome pairing was studied in a number of hybrids involving a 56-chromosome wheat-Agropyron derivative, PW 327. PW 327 originated from the cross, Triticum aestivum cv. Chinese Spring (Chinese Spring × A. elongatum, 2n = 70). In hybrids between PW 327 and T. aestivum a number of multivalent chromosome associations were formed at metaphase I. These multivalents result from interchanges which occurred among wheat chromosomes 1A, 1D, 2A, 2D, 4D and 6D of PW 327. One chromosome of the Agropyron chromosome set of PW 327 occasionally pairs with wheat chromosome 3B. The rest of the Agropyron chromosomes present in PW 327 do not pair with the chromosomes of T. aestivum. It is proposed that the set of Agropyron chromosomes present in PW 327 is not an intact genome of decaploid A. elongatum but rather a modified synthetic genome combining chromosomes and/or chromosome segments from different genomes of the Agropyron parent. The incorporation of duplication-deletions into synthetic genomes of natural polyploids is discussed and it is shown that the set of Agropyron chromosomes which is present in PW 327 carries at least one such duplication-deletion. Pairing between chromosomes of diploid and decaploid A. elongatum was studied in a 56-chromosome hybrid from a cross between an amphiploid, T. aestivum × A. elongatum (2n = 14), and PW 327. It appeared that at least four chromosomes of these two Agropyrons occasionally paired with each other in this hybrid in which the diploidizing system of wheat was active. The relationship between chromosomes of diploid and decaploid A. elongatum is discussed.


1986 ◽  
Vol 28 (1) ◽  
pp. 1-6 ◽  
Author(s):  
A. Charpentier ◽  
M. Feldman ◽  
Y. Cauderon

The degree and pattern of chromosomal pairing at first meiotic metaphase were analyzed in several lines of hexaploid Agropyron junceum (2n = 42; genome J1J1J2J2EE), in the F1 hybrid between this species and common wheat, and in the backcrossed progeny of the hybrid to common wheat. Hexaploid A. junceum exhibited a strict bivalent pairing despite the relatedness of its genomes. Chromosomes of the J1 and J2 genomes of Agropyron paired in the F1 hybrid and in the backcross derivatives, in the presence of the Ph1 gene of common wheat. It was concluded that the corresponding chromosomes of the J1 and J2 genomes are distant homologues. It is assumed that the strict bivalent pairing in A. junceum is brought about by a gene system, similar to that found in several autotetraploid species.Key words: Agropyron junceum, Triticum aestivum, common wheat, wheat × Agropyron hybrids, chromosome pairing, bivalentization.


1978 ◽  
Vol 56 (8) ◽  
pp. 1091-1094 ◽  
Author(s):  
K. Kobrehel

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.


1984 ◽  
Vol 26 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Giampiero Gualandi ◽  
Carla Ceoloni ◽  
Moshe Feldman ◽  
Lydia Avivi

Lines of common wheat cv. 'Chinese Spring' carrying different doses of the Ph1 gene, located on the long arm of chromosome 5B were treated with the antimitotic agents griseofulvin and isopropyl-N-phenyl-carbamate (IPC). Treatments with low griseofulvin concentrations and IPC resulted mainly in the production of a high percentage of cells exhibiting spindle disorganization at metaphase and multipolar cells at anaphase–telophase. These treatments did not differentially affect the tested genotypes. On the other hand, higher griseofulvin concentrations induced the appearance of frequent C-metaphases and C-anaphases because of complete disruption of the spindle microtubules; in such cases, more pronounced sensitivity was observed in a line lacking the Ph1 gene than in lines disomic and tetrasomic for chromosome 5B. From this evidence it can be concluded that subcellular structures regulating microtubule organization and orientation, which are apparently the target of IPC and low griseofulvin concentrations, are not related to the action of the Ph1 gene. Rather, tubulin–microtubules equilibrium, which is affected by colchicine and high griseofulvin concentrations, is influenced by the action of this gene. Thus, the Ph1 gene product may correspond to a tubulin or a microtubule-associated protein which in turn stabilizes microtubule structure. In either case, the equilibrium tubulin–microtubules would be shifted towards microtubules in plants containing two doses of Ph1 and even more in plants containing an extra dose of this gene.Key words: spindle, Triticum, microtubules, antitubulins, griseofulvin.


1986 ◽  
Vol 28 (2) ◽  
pp. 240-246 ◽  
Author(s):  
C. Ceoloni ◽  
I. Strauss ◽  
M. Feldman

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.


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