Cytogenetic studies of progeny from the intergeneric crosses Elymus × Hordeun and Elymus × Secale

Genome ◽  
1990 ◽  
Vol 33 (3) ◽  
pp. 425-432 ◽  
Author(s):  
Bao-Rong Lu ◽  
Björn Salomon ◽  
Roland von Bothmer
Keyword(s):  
Intergeneric Hybrid ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Homoeologous Chromosome ◽  
Intergeneric Crosses ◽  
Homoeologous Chromosome Pairing ◽  
Cytogenetic Studies ◽  
Elymus Species ◽  
Hordeum Vulgare Ssp

Meiotic pairing was studied in three Elymus species, E. pseudonutans (2n = 28), E. shandongensis (2n = 28), and E. semicostatus (2n = 28), as well as their dihaploids (2n = 14) which were produced from the intergeneric crosses E. pseudonutants × Hordeum vulgare ssp. spontaneum, E. shandongensis × Triticum aestivum, and E. semicostatus × H. bulbosum. An average of 12.82 I + 0.55 II + 0.03 III; 12.59 I + 0.65 II + 0.01 III, and 12.70 I + 0.76 II + 0.02 III per cell characterized meioses in the dihaploids, respectively. Intergeneric hybrids (2n = 21) of the three species were also obtained with diploid Secale cereal and S. montanum. Meiotic configurations of the hybrids were 14.64 I + 2.82 II + 0.20 III + 0.01 IV and 16.38 I + 2.02 II + 0.16 III for two combinations of E. pseudonutans × S. cereale; 15.59 I + 2.62 II + 0.08 III and 19.63 I + 0.65 II for E. shandongensis × S. cereale and E. semicostatus × S. montanum, respectively. A large number of chromosomes were involved in secondary associations in the different combinations. The study revealed (i) low affinity between S and Y genomes in the investigated Elymus species, (ii) a certain degree of homoeology between genomes of Elymus (S or Y) and rye (R), and (iii) that the rye genome affects homoeologous chromosome pairing between different genomes in the Elymus species.Key words: Elymus, Hordeum, Secale, dihaploid, chromosome elimination, intergeneric hybrid, meiotic pairing.

Coenocytism, ameiosis, and chromosome diminution in intergeneric hybrids in the perennial Triticeae

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 766-775 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Intergeneric Hybrid ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Pollen Grain ◽  
Unreduced Gamete ◽  
Pollen Mother Cells ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Mother Cells ◽  
Pollen Grain Wall

Three different pathways of ameiotic microsporogenesis were observed in some intergeneric hybrids of the perennial Triticeae grasses. In one of the hybrids between Pseudoroegneria spicata ssp. inermis and Psathyrostachys juncea, pollen mother cells remained as premeiotic interphase cells when the pollen grain wall started to form. The microspores in such an ameiotic plant are presumably unreduced. Coenocyte formation coupled with ameiosis occurred in two hybrid plants of Psathyrostachys huashanica × Secale montanum. Less than 10% of the pollen mother cells had one nucleus. An average of 4.44 nuclei, ranging from 1 to 25 per pollen mother cell, was observed. The nuclei in coenocytes remained unfused when the pollen grain wall was formed. Nucleus splitting followed by cytoplasmic budding or cleavage, possibly a process of chromosome diminution or elimination, replaced meiotic divisions in most of the pollen mother cells in one plant of Leymus angustus × Hordeum bulbosum and two plants of Thinopyrum elongatum × Psathyrostachys juncea. It is evident that these meiotic abnormalities are under genetic control. Probable locations for these genes controlling these phenomena are suggested.Key words: coenocyte, ameiosis, chromosome diminution, chromosome elimination, microsporogenesis, unreduced gamete, polyploidy, intergeneric hybrid.

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.

Synaptonemal complex analysis of hybrid cattle. III. Meiotic pairing mechanisms in F1 Brahman × Hereford hybrids

Genome ◽  
1991 ◽  
Vol 34 (2) ◽  
pp. 228-235 ◽  
Author(s):  
A. E. Dollin ◽  
J. D. Murray ◽  
C. B. Gillies
Keyword(s):  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Complex Analysis ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Meiotic Pairing ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Synaptonemal Complex Analysis ◽  
Complex Hybrid

The mechanisms of homoeologous chromosome pairing were studied in synaptonemal complex (SC) spreads of F1 Brahman (Bos indicus) × Hereford (Bos taurus) cattle. The most common SC abnormalities were bivalents with partial pairing failure and interlocks. While C-band polymorphisms could underlie most of the SC abnormalities observed in the full-blood cattle, other causes seem also to be contributing in the hybrids. The pattern of the abnormalities indicates that genie differences between the species were probably involved. Pachytene substaging data suggest that in some spreads, early pachytene bivalents with partial pairing failure may achieve complete synapsis or may be converted to interlocks by late pachytene.Key words: synaptonemal complex, hybrid cattle, interlocks.

Assessment of chromosome associations in haploids and their parental accessions in Hordeum

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 204-210 ◽  
Author(s):  
R. von Bothmer ◽  
N. C. Subrahmanyam
Keyword(s):  
Genetic Variation ◽  
Chromosome Pairing ◽  
Diploid Species ◽  
Meiotic Behaviour ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Homologous Pairing ◽  
Homoeologous Chromosome Pairing ◽  
Chromosome Associations

Meiotic pairing was studied in the following species and their haploid derivatives: Hordeum cordobense 2x, H. marinum 2x and 4x, H. secalinum 4x, H. capense 4x, H. jubatum 4x, H. brachyantherum 4x and 6x, H. lechleri 6x, and H. procerum 6x. The study revealed (i) homologous pairing in diploid species and very little nonhomologous associations in their mono-haploids; (ii) the alloploid nature of the polyploid taxa; (iii) a certain degree of homoeologous pairing in polyhaploids despite the diploid-like meiotic behaviour of the polyploids; (iv) genetic variation in the suppression of homoeologous chromosome pairing in different Hordeum species.Key words: Hordeum, meiotic pairing, haploids.

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.

Variation in induction of homoeologous chromosome pairing in 6x Aegilops crassa by genomes of six different species of Secale

1985 ◽  
Vol 27 (5) ◽  
pp. 531-537 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Control System ◽  
Chromosome Pairing ◽  
Meiotic Pairing ◽  
Homoeologous Chromosome ◽  
Homoeologous Chromosome Pairing ◽  
Total Dna ◽  
Heterochromatin Content ◽  
Aegilops Crassa

Meiosis was studied in hybrids between Aegilops crassa (Boiss.) Hitch and Hensl. (2n = 6x = 42) having the genomes DD2MCr and six species of Secale. The chiasmata frequency per cell ranged from 6.86 in hybrids with S. cereale to 9.93 in hybrids with S. montanum ssp. dalmaticum. These results provide further evidence that a meiotic pairing control system is operating in Ae. crassa. The Secale genotypes suppress the function of this system in a manner which was inversely related to their heterochromatin content and total DNA content.Key words: Secale, Aegilops, chiasmata, meiotic pairing control, hybrids.

Intergeneric hybrids between Thinopyrum and Psathyrostachys (Triticeae)

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 845-849 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Genome Analysis ◽  
Parental Species ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Green Leaves ◽  
Psathyrostachys Juncea ◽  
Basic Genome ◽  
Chromosome Associations ◽  
Thinopyrum Elongatum ◽  
First Time

Intergeneric hybrids were synthesized for the first time from the diploid crosses Thinopyrum elongatum (JeJe) × Psathyrostachys juncea (NjNj), T. elongatum × P. fragilis (NfNf), T. bessarabicum (JbJb) × P. huashanica (NhNh), and T. bessarabicum × P. juncea, as well as from a cross between the amphidiploid of T. bessarabicum × T. elongatum (JbJbJeJe) and P. juncea. Spikes of these hybrids are morphologically intermediate between those of the parental species. Double spikelets occurred occasionally at central nodes of the spikes. Glaucous blue leaves appeared in the F1 only in the cross T. bessarabicum × P. huashanica, suggesting that the gene(s) for glaucous blue leaves in T. bessarabicum is (are) recessive to a gene(s) for green leaves in P. juncea but is (are) dominant to that for yellowish green leaves in P. huashanica. Meiotic pairing at metaphase I in these diploid (JN) and triploid (JJN) hybrids revealed a very low level of homology between the basic J and N genome. Therefore, the J and N genomes are nonhomologous and justifiably represented by different genome symbols. The triploid hybrids exhibited a pattern of chromosome associations that substantiated the earlier conclusion that the genomes in T. bessarabicum and T. elongatum are two versions of a basic genome (J). These hybrids will be useful in genome analysis, forming new Leymus species with the J and N genomes and broadening the diversity in the genus Pascopyrum with the SHJN genomes.Key words: hybrid, Thinopyrum, Psathyrostachys, genome.

scholarly journals VARIATION AMONG PERENNIAL RYEGRASS x TALL FESCUE PLANTS FROM TISSUE CULTURE

1988 ◽  
pp. 81-86
Author(s):  
A.G. Scott ◽  
D.W.R. White
Keyword(s):  
Tissue Culture ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Chromosome Doubling ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Hybrid Plants ◽  
Spontaneous Chromosome

Tissue culture was used in an attempt to obtain a fertile perennial ryegrass x tall fescue hybrid. Regenerated hybrid plants were found to be morphologically variable and contain extensive chromosome rearrangements. Spontaneous chromosome doubling had occurred as well as chromosome elimination. though no fertile hybrid plants have been obtained to date. Keywords: somaclonal variation, Lolium perenne, Festuca arundinacea, intergeneric hybrids

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