Hybrids of Hordeum californicum and 2x H. brevisubulatum s.l. with Agropyron caninum

1985 ◽  
Vol 27 (4) ◽  
pp. 380-386 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Floral Morphology ◽  
Embryo Rescue ◽  
Intergeneric Hybrid ◽  
Bivalent Formation ◽  
The Difference ◽  
Agropyron Caninum ◽  
Hordeum Species

Two diploid Hordeum species, H. californicum (2n = 2x = 14) and H. brevisubulatum s.l. (2n = 2x = 14), were used successfully to produce hybrids with Agropyron caninum (2n = 4x = 28) through embryo rescue techniques. The floral morphology of the hybrids was intermediate between the parents in each case. Both hybrids were triploids (2n = 3x = 21), and chromosome pairing exhibited a mean of 3.86 bivalents in the hybrid with H. californicum and a mean of 5.53 bivalents in the hybrid with H. brevisubulatum. Bivalent formation was attributed to a common genome between the diploid Hordeum species and the tetraploid A. caninum. It could not be ascertained whether the difference in the two hybrids was due to a difference in the degree of homology or difference in meiotic control mechanisms.Key words: Hordeum, Agropyron, homeology, triploid, intergeneric hybrid.

Genetic control of meiotic chromosome pairing in polyploids in the genus Hordeum

1985 ◽  
Vol 27 (5) ◽  
pp. 515-530 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Meiotic Chromosome ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Major Locus ◽  
In The Wild ◽  
Hordeum Species ◽  
Homoeologous Chromosomes ◽  
Existing Data

Existing data on meiosis in hexaploid and tetraploid species of Hordeum, their respective polyhaploids, and intergeneric – interspecific hybrids indicate that a meiotic pairing control system exists in this genus. The system is probably polygenic and it is therefore unlikely that a major locus such as Ph in Triticum controls chromosome pairing. It is more efficient in the tetraploids than hexaploids, permitting some intergenomic pairing in the latter. In the polyhaploids the pairing control is somewhat hemizygous ineffective. The pairing of homoeologous chromosomes in the wild polyploid Hordeum species is generally inhibited by H. vulgare and variably enhanced by genomes of Secale species.Key words: Hordeum, synapsis regulation, intergeneric hybrid, polyhaploids, hemizygous.

Intergeneric hybrids of Hordeum vulgare with Agropyron caninum and A. dasystachyum

1985 ◽  
Vol 27 (4) ◽  
pp. 387-392 ◽  
Author(s):  
George Fedak
Keyword(s):  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Meiotic Chromosome ◽  
Intergeneric Hybrids ◽  
Spindle Fibre ◽  
Chromosome Behavior ◽  
Paternal Parent ◽  
Agropyron Caninum

Hybrids were obtained by pollinating Hordeum vulgare cv. Betzes with Agropyron caninum (4x) and A. dasystachyum (4x) at frequencies of 1.4 and 6.1% of pollinated florets, respectively. The hybrids were sterile and phenotypically resembled the paternal parent, except for floret structure which was intermediate between the parental types. Chromosome pairing at meiosis was very low and thus provided no indication of homoeology between parental genomes. Abnormal meiotic chromosome behavior in meiocytes that occurred in sectors on the 'Betzes' × A. dasystachyum hybrid was attributed to abnormal spindle fibre function.Key words: intergeneric hybrids, Hordeum vulgare, Agropyron caninum, Agropyron dasystachyum.

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.

Phylogeny in the genus Hordeum based on nucleotide sequences closely linked to the vrs1 locus (row number of spikelets)

Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 973-981 ◽  
Author(s):  
Takao Komatsuda ◽  
Ken-ichi Tanno ◽  
Björn Salomon ◽  
Tomas Bryngelsson ◽  
Roland von Bothmer
Keyword(s):  
Nuclear Dna ◽  
Sister Group ◽  
Single Copy ◽  
Nucleotide Sequences ◽  
Restriction Maps ◽  
Deletion Event ◽  
Single Base ◽  
Genome Group ◽  
The Difference ◽  
Hordeum Species

The phylogenetic relationship between four basic genomes designated H, I, Xa, and Xu in the genus Hordeum was studied using a nuclear DNA sequence. The sequence, cMWG699, is single copy in the H. vulgare genome, and tightly linked to the vrs1 locus which controls two- and six-rowed spikes. DNA fragments homologous to cMWG699 were amplified from diploid Hordeum species and the nucleotide sequences were determined. A phylogeny based on both base substitutions and an insertion-deletion event showed that the H- and Xa-genome groups are positioned in one monophyletic group indicating that the Xa-genome taxa should be included in the H-genome group. The large H-genome group is highly homogeneous. The I and Xu genomes are distinctly separated from H and Xa, and form sister groups. Another phylogeny pattern based on data excluding the insertion-deletion gave a result that the Xa genome forms a sister group to the H-genome group. The difference between the H and Xa genomes was affected only by a single base insertion-deletion event, thus the H and Xa genomes are likely to be closely related. The I and Xu genomes were again distinctly separated from the H and Xa genomes.Key words: genome DNA, molecular markers, restriction maps, barley, Psathyrostachys.

Analysis of synaptonemal complexes and chromosome pairing at metaphase I in the diploid intergeneric hybrid Lolium multiflorum × Festuca drymeja

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Hum M. Thomas ◽  
W. G. Morgan
Keyword(s):  
Chromosome Pairing ◽  
Complex Analysis ◽  
Lolium Multiflorum ◽  
Intergeneric Hybrid ◽  
Chiasma Formation ◽  
Genotypic Effect ◽  
Synaptonemal Complexes ◽  
Dna Values ◽  
Synaptonemal Complex Analysis ◽  
Metaphase I

The synaptonemal complexes in the diploid hybrid Lolium multiflorum × Festuca drymeja were examined by the surface spreading technique, and chromosome pairing at metaphase I was analysed. Synaptonemal complex analysis revealed "illegitimate" pairing, including multivalents and foldback pairing. At metaphase I, most chiasmata were between chromosomes of the same genome, and again multivalents were found. It was concluded that most synaptonemal complexes resulted in chiasma formation. The effects of the large differences in DNA values of the two species and the possible genotypic effect of F. drymeja on chromosome pairing are discussed.Key words: Lolium-Festuca, synaptonemal complexes, nonhomologous pairing, DNA values.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

THE SIGNIFICANCE OF MEIOTIC CHROMOSOME PAIRING IN TETRAPLOID (2n = 28) BROMUS PUMPELLIANUS SCRIBN. SSP. DICKSONII

1972 ◽  
Vol 14 (4) ◽  
pp. 763-771 ◽  
Author(s):  
K. C. Armstrong
Keyword(s):  
Chromosome Pairing ◽  
High Frequency ◽  
Chiasma Frequency ◽  
Karyotype Analysis ◽  
Meiotic Chromosome ◽  
Low Frequency ◽  
Meiotic Chromosome Pairing ◽  
Ring Bivalents ◽  
Bivalent Formation

Bivalent formation was predominant at meiosis in B. pumpellianus ssp. dicksonii. The average in 15 plants ranged from 11.38 to 13.77 bivalents per cell. The high chiasma frequency (23.41-26.74) was a reflection of the high frequency of ring bivalents (9.48-12.42). A low frequency of quadrivalents occurred (0.06-1.22). A karyotype of this species was presented from both a highly contracted and moderately contracted cell and the differences between these two were noted. Four satellites were found, two large and two minute. There were 3-5 submedian and 5-7 median chromosomes depending on the cell studied. In addition two subterminal chromosomes were present. The meiotic and karyotype analysis suggest a deviation from an autotetraploid behaviour, but the presence of quadrivalents and similarities between pairs in the karyotype suggested closely related genomes. Alternatively it was considered that the quadrivalents could be due to translocation heterozygotes. The implications of these results were discussed in relation to the reported meiotic events in the octoploids, B. inermis and B. pumpellianus.

Location of the Ph1 locus in the metaphase chromosome map and the linkage map of the 5Bq arm of wheat

1986 ◽  
Vol 28 (4) ◽  
pp. 511-519 ◽  
Author(s):  
R. Jampates ◽  
J. Dvořák
Keyword(s):  
Linkage Map ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chromosome Rearrangement ◽  
Distal Region ◽  
Crossing Over ◽  
Chromosome 5B ◽  
Ph1 Locus ◽  
The Difference ◽  
Two Populations

Heterogenetic chromosome pairing in wheat is prevented by the Ph1 locus on the q (=L) arm of chromosome 5B. Two durum wheat cv. Cappelli structural mutants with rearranged 5Bq chromosome arms were investigated to determine the location of the Ph1 locus in the metaphase map and the linkage map of the arm. One of the mutants, Cap5Bq−, has a deletion of subregion 5Bq12.3 between C-bands 5Bq12.2 and 5Bq21 and the other one, Cap5Bq+, has the same subregion duplicated. Each mutant and standard cv. Cappelli were crossed with Aegilops kotschyi, Ae. ovata, Ae. cylindrica, Ae. ventricosa, Ae. juvenalis, and "Ae. crassa 6x." Hybrids involving Cap5Bq− had higher levels of chromosome pairing than those involving cv. Cappelli, whereas those involving Cap5Bq+ had lower levels of pairing than those involving cv. Cappelli. Cap5Bq− was crossed with cv. Cappelli and the F1 was hybridized with Ae. kotschyi and Ae. ventricosa. All hybrids with the 5Bq− chromosome had a higher level of chromosome pairing than those with the standard chromosome. Cap5Bq+ was crossed with cv. Cappelli and the F1 was hybridized with Ae. kotschyi. Most hybrids with the 5Bq+ chromosome had a lower level of chromosome pairing than those with the standard chromosome. Because the difference between the means of the two populations was small (0.43 chiasmata per cell) and the distributions overlapped, the strength of the linkage between the duplication and reduced pairing could not be determined; the data, nevertheless, showed that the reduced pairing must be strongly, if not completely, linked to the duplication. It is therefore concluded that the Ph1 locus is in the euchromatic subregion 5Bq12.3, 5Bq− is a null for Ph1, and 5Bq+ has two Ph1 loci. The 5Bq+ chromosome was substituted into Triticum aestivum cv. Chinese Spring, the substitution was crossed with cv. Chinese Spring ditelosomic 5Bq, and the F1 was crossed with cv. Chinese Spring monosomic 5B. Recombination of C-bands relative to each other and the centromere was determined with the objective of determining the distribution of crossing-over along the 5Bq arm and the linkage of the subregion 5Bq12.3 with the centromere. The distibution of crossing-over was greatly distorted, most occurred in the distal region of the arm. The subregion 5Bq12.3 showed a tight linkage with the centromere, even though it is in the middle of the 5Bq arm. It is proposed to designate the cv. Cappelli Ph1− mutation as ph1c.Key words: Triticum, map distortion, homoeologous pairing, chromosome pairing, chromosome rearrangement.

GENOME RELATIONSHIPS IN BROMUS ERECTUS, B. PUMPELLIANUS SSP. DICKSONII AND B. PUMPELLIANUS

1975 ◽  
Vol 17 (3) ◽  
pp. 391-394
Author(s):  
K. C. Armstrong
Keyword(s):  
Genetic Control ◽  
Chromosome Pairing ◽  
Low Frequency ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Bivalent Formation ◽  
Bromus Erectus

Chromosome pairing was studied in hexaploid (2n = 42) hybrids of B. erectus (2n = 28) × B. pumpellianus (2n = 56) and B. pumpellianus ssp. dicksonii (2n = 28) × B. pumpellianus. Chromosome pairing in the B. erectus × B. pumpellianus hybrid was complete with predominantly bivalent formation and a low frequency of quadrivalents. The pairing results support the contention that B. pumpellianus is an autoalloploid with an AAAABBBB genome formula. The B. pumpellianus ssp. dicksonii × B. pumpellianus hybrid has an AAABBB genome formula. The presence of quadrivalents, hexavalents and cells containing a total number of bivalents or bivalents plus trivalents in excess of 14 indicated pairing between the A and B genomes. However, a high univalent frequency showed that the A and B genomes were homoeologous rather than homologous. Evidence for genetic control of homoeologous chromosome pairing and homoeologous differentiation between the genomes of the species is discussed.

Cytogenetic studies of interspecific hybrids between diploid species of Festuca

1986 ◽  
Vol 28 (6) ◽  
pp. 921-925 ◽  
Author(s):  
W. G. Morgan ◽  
Hugh Thomas ◽  
M. Evans ◽  
M. Borrill
Keyword(s):  
Genome Size ◽  
Chromosome Pairing ◽  
Dna Content ◽  
Interspecific Hybrids ◽  
Parental Species ◽  
Diploid Species ◽  
Chromosome Size ◽  
Cytogenetic Studies ◽  
The Difference

Chromosome pairing in hybrids between diploid species of Festuca is described. The chromosome complements of the species from different taxonomic sections vary in chromosome size and DNA content. In interspecific hybrids involving species of the section Montanae there was a relationship between the difference in DNA content of the parental species and chromosome pairing in the F1 hybrids. The larger the difference between the DNA content of the parental species, the more pronounced the failure of chromosome pairing in the F1 hybrids. Factors other than divergence in genome size were also shown to have an effect on chromosome pairing in other hybrid combinations.Key words: chromosome pairing, DNA content, Festuca, hybrids (interspecific).

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