Effect of nullisomy for D-genome chromosomes and chromosome 5B on the cytological characteristics of pentaploid Triticum aestivum × T. dicoccoides hybrids

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 221-224
Author(s):  
G. Ganeva ◽  
B. Bochev
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Functional Ability ◽  
Meiotic Chromosome ◽  
Specific Effect ◽  
Homoeologous Chromosome ◽  
D Genome ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
Cytological Characteristics

The effect of nullisomy for D-genome chromosomes and chromosome 5B on the meiotic behaviour of pollen mother cell chromosomes of pentaploid F1 hybrids of Triticum aestivum (cv. Bezostaya 1) × T. dicoccoides (Körn) was studied. The functional ability of female gametes with diverse chromosome constitution and the frequency of their inheritance in BC1 was assessed. Absence of individual T. aestivum D-genome chromosomes had a specific effect on meiotic chromosome pairing. The genetic systems involving chromosome 5B of the two species did not have the same effect on homologous and homoeologous chromosome pairing. Chromosome 5B of T. dicoccoides reduced bivalent pairing and increased multivalent associations. In BC1 the frequency of female gametes with n = 16–18 chromosomes was highest. Key words: nullisomy, chromosome pairing, Triticum, pentaploid hybrids.

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.

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.

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 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.

scholarly journals The position of a locus on chromosome 5B of Triticum aestivum affecting homoeologous meiotic pairing

1971 ◽  
Vol 18 (3) ◽  
pp. 329-339 ◽  
Author(s):  
A. M. Wall ◽  
Ralph Riley ◽  
M. D. Gale
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Single Locus ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
Mutant Locus ◽  
Homoeologous Chromosomes ◽  
Pairing Behaviour

SUMMARYAn investigation was made of the chromosomal position of the mutant locus, in Mutant 10/13 of Triticum aestivum (2n = 6x = 42), affecting homoeologous chromosome pairing at meiosis. In hybrids between Mutant 10/13 and rye (Secale cereale 2n = 14), homoeologous chromosomes frequently pair at meiosis although normally, in wheat-rye hybrids, this happens infrequently.The association of the mutant condition with chromosome 5B was determined by (i) the absence of segregation in hybrids obtained when Mutant 10/13 monosomic 5B was pollinated by rye; (ii) the occurrence of trisomie segregation for pairing behaviour in 28-chromosome wheat-rye hybrids, obtained from SB trisomie wheat parents with two 5B chromosome from a non-mutant and one from a mutant parent; (iii) the absence of segregation for pairing behaviour in the 29-chromosome wheat-rye hybrids obtained from the same trisomie wheat parents.The alternative pairing behaviours segregated independently of the centromere when wheat plants that were simultaneously heteromorphic, 5BL telocentric/5B complete, and heterozygous for the Mutant 10/13 state, were pollinated by rye. The alternative chromosome-pairing patterns segregated to give a ratio not different from 1:1, so that the association of homoeologous pairing with Mutant 10/13 probably derived from the occurrence of mutation at a single locus on 5BL. In the disomic heteromorphic state, 5BL was 91 map units in length.Trisomie wheats with two complete 5B chromosomes and one 5BL telocentric, that were also heterozygous for the Mutant 10/13 condition, were pollinated by rye. Among the resulting 28-chromosome hybrids there was a 2:1 segregation of hybrids with low pairing: high (homoeologous) pairing and also of hybrids with complete 5B: telocentric 5BL. However, there was no evidence of linkage in this trisomie segregation. All the 29-chromosome hybrids from this cross had low pairing and it could be concluded that the single mutant allele, in Mutant 10/13, was recessive. In the trisomie condition, relative to a simplex situation, 5BL was 33·05 map units in length.The critical locus on 5BL was designated Pairing homoeologous. The normal dominant allele was symbolized Ph and the recessive allele, in Mutant 10/13, ph.The prevention of homoeologous pairing by the activity of a single locus makes the evolution of the regular meiotic behaviour of T. aestivum more readily comprehensible.

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.

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.

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