Meiotic pairing of specific chromosome arms in triploid rye

1984 ◽  
Vol 26 (6) ◽  
pp. 717-722 ◽  
Author(s):  
Elena Benavente ◽  
Juan Orellana
Keyword(s):  
Meiotic Pairing ◽  
Preferential Pairing ◽  
Specific Chromosome ◽  
C Banding ◽  
Expected Values ◽  
Metaphase I

From the meiotic configurations at metaphase I of triploid plants it is possible to estimate the frequency of trivalent pairing (f) at pachytene. Although the meiotic pairing frequencies for specific chromosome arms (detected by C-banding) could not always be estimated owing to restrictions of the model, a good fit between observed and expected values was generally found. One case of preferential pairing between heteromorphic chromosome arms was observed. Heterochromatin apparently does not play any role in determining pairing preferences.Key words: triploid rye, C-heterochromatin, meiotic pairing.

Chromosome pairing in hybrids of ph1b mutant wheat with rye

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 639-646 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
R. Giraldez ◽  
P. G. Goicoechea
Keyword(s):  
Common Wheat ◽  
Chromosome Pairing ◽  
Chromosome Structure ◽  
Preferential Pairing ◽  
C Banding ◽  
Homoeologous Chromosomes ◽  
Metaphase I

Metaphase I pairing was studied in five ph1b mutant wheat × rye hybrids to verify the presence of translocations between homoeologous chromosomes in ph1b mutant wheat and to establish the pairing homoeology between wheat and rye chromosomes. Three 5B-deficient ABDR hybrids with standard chromosome structure were used as controls. Chromosomes 1R and 5R of rye and most wheat chromosomes, as well as their arms, were identified by means of C-banding. The presence of 5BS in ph1b hybrids raised the overall pairing level. The pattern of pairing between wheat chromosomes in ph1b hybrids, as in 5B-deficient hybrids, was characterized by the occurrence of preferential pairing between chromosomes of the A and D genomes in most homoeologous groups. The existence of a double translocation involving 4BL, 5AL, and 7BS in common wheat was confirmed. Deviation from the standard pairing pattern suggested the existence of a translocation involving 1BL and 1DL in one ph1b ABDR plant and another translocation involving 3AL and 3DL in three other ph1b hybrids. In ph1b hybrids, wheat – rye pairing was relatively frequent for 1RL, 5RL, and an arm of a metacentric rye chromosome, probably 2R, that is homoeologous to 2BL, and the homoeologous arms of 2A and 2D. The existence of a translocation involving 5RL and 4RL in rye was confirmed.Key words: homoeologous, homologous, 5B-deficient, translocations, C-banding.

Pairing affinities of the B- and G-genome chromosomes of polyploid wheats with those of Aegilops speltoides

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 814-819 ◽  
Author(s):  
S Rodríguez ◽  
B Maestra ◽  
E Perera ◽  
M Díez ◽  
T Naranjo
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Triticum Turgidum ◽  
Aegilops Speltoides ◽  
Meiotic Pairing ◽  
Triticum Timopheevii ◽  
C Banding ◽  
Tetraploid Wheats ◽  
B Genome ◽  
Metaphase I

Chromosome pairing at metaphase I was studied in different interspecific hybrids involving Aegilops speltoides (SS) and polyploid wheats Triticum timopheevii (AtAtGG), T. turgidum (AABB), and T. aestivum (AABBDD) to study the relationships between the S, G, and B genomes. Individual chromosomes and their arms were identified by means of C-banding. Pairing between chromosomes of the G and S genomes in T. timopheevii × Ae. speltoides (AtGS) hybrids reached a frequency much higher than pairing between chromosomes of the B and S genomes in T. turgidum × Ae. speltoides (ABS) hybrids and T. aestivum × Ae. speltoides (ABDS) hybrids, and pairing between B- and G-genome chromosomes in T. turgidum × T. timopheevii (AAtBG) hybrids or T. aestivum × T. timopheevii (AAtBGD) hybrids. These results support a higher degree of closeness of the G and S genomes to each other than to the B genome. Such relationships are consistent with independent origins of tetraploid wheats T. turgidum and T. timopheevii and with a more recent formation of the timopheevi lineage.Key words: Triticum turgidum, Triticum timopheevii, Aegilops speltoides, meiotic pairing, evolution, C-banding.

Rye C-banding patterns and meiotic stability of hexaploid triticale (× Triticosecale) selections differing in kernel shriveling

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 686-689 ◽  
Author(s):  
Charles M. Papa ◽  
R. Morris ◽  
J. W. Schmidt
Keyword(s):  
Secale Cereale ◽  
Chromosome Banding ◽  
Agronomic Performance ◽  
Hexaploid Triticale ◽  
Kernel Development ◽  
Banding Patterns ◽  
C Banding ◽  
Meiotic Stability ◽  
Metaphase I

Two winter hexaploid triticale populations derived from the same cross were selected on the basis of grain appearance and agronomic performance. The five lines from 84LT402 showed more kernel shriveling than the four lines from 84LT401. The derived lines were analyzed for aneuploid frequencies, rye chromosome banding patterns, and meiotic stability to detect associations with kernel development. The aneuploid frequencies were 16% in 84LT401 and 18% in 84LT402. C-banding showed that both selection groups had all the rye chromosomes except 2R. The two groups had similar telomeric patterns but differed in the long-arm interstitial patterns of 4R and 5R. Compared with lines from 84LT402, those from 84LT401 had significantly fewer univalents and rod bivalents, and more paired arms at metaphase I; fewer laggards and bridges at anaphase I; and a higher frequency of normal tetrads. There were no significant differences among lines within each group for any meiotic character. Since there were no differences within or between groups in telomeric banding patterns, the differences in kernel shriveling and meiotic stability might be due to genotypic factors and (or) differences in the interstitial patterns of 4R and 5R. By selecting plump grains, lines with improved kernel characteristics along with improved meiotic stability are obtainable.Key words: triticale, meiotic stability, C-banding, Secale cereale, heterochromatin.

Evidence of nonchiasmate bonds at metaphase I in inbred rye

1984 ◽  
Vol 26 (4) ◽  
pp. 409-414 ◽  
Author(s):  
M. C. Cermeño ◽  
J. Orellana ◽  
J. R. Lacadena
Keyword(s):  
Secale Cereale ◽  
Chiasma Frequency ◽  
Meiotic Pairing ◽  
Secale Cereale L ◽  
Chromosome 1R ◽  
Metaphase I

The loss of bound chromosome arms through early, middle, and late metaphase I has been analyzed in a plant of inbred rye (Secale cereale L.) heterozygous for a terminal heterochromatic C-band of the long arm of chromosome 1R. From the increase in the number of univalent pairs due to bound arm loss, and from the comparison between the frequencies of bound arms at metaphase I and recombinant chromosomes at anaphase I, it is concluded that some of the chromosome bonds appearing at metaphase I are actually nonchiasmate associations that can be considered as remnants of prophase pairing. Conclusions concerning recombination obtained solely from the analysis of chiasma frequency measured as bound arms may be invalid.Key words: inbred rye, C-heterochromatin, meiotic pairing, nonchiasmate bonds.

C-banding and DNA content in seven species of Tenebrionidae (Coleoptera)

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 834-839 ◽  
Author(s):  
C. Juan ◽  
E. Petitpierre
Keyword(s):  
Genome Size ◽  
X Chromosome ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
C Banding ◽  
Metaphase I

The relative amount of C-banded heterochromatin varies strikingly in seven species of tenebrionid beetles, from 25 to 58%, but most species show procentric bands only. Nevertheless, Gonocephalum patruele exhibits an almost completely heterochromatic X chromosome. The nuclear DNA content of Feulgen-stained spermatids has yielded up to a threefold difference, from 0.27 to 0.86 pg, which is not completely in accordance with the amount of C-banded heterochromatin. However, the genome sizes correlate significantly with the total chromosome areas at metaphase I and with the spermatid areas. Furthermore, the genome sizes agree with the subfamilial taxonomic groupings of these tenebrionids.Key words: Tenebrionidae, genome size, C-banding.

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.

Homoeologous pairing and recombination between the long arms of group 1 chromosomes in wheat × rye hybrids

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 293-301 ◽  
Author(s):  
T. Naranjo ◽  
P. Fernández-Rueda ◽  
P. G. Goicoechea ◽  
A. Roca ◽  
R. Giráldez
Keyword(s):  
Banding Pattern ◽  
Homoeologous Pairing ◽  
Parental Type ◽  
C Banding ◽  
Group 1 Chromosomes ◽  
The Relationship ◽  
Double Recombinant ◽  
Group 1 ◽  
Metaphase I

The relationship between homoeologous pairing at metaphase I and recombination at anaphase I between the arms 1AL, 1BL, 1DL, and 1RL was analyzed in ph1b, 5B-deficient, and ph2b wheat × rye hybrids. All four arms could be identified at metaphase I, as well as the arms 1BL and 1RL at anaphase I, by means of C-banding. On the basis of the C-heterochromatin constitution that 1BL and 1RL showed at anaphase I and that association at metaphase I was essentially homoeologous, the following anaphase I chromosome types could be distinguished: parental type, single and double recombinant types between 1BL and 1AL or 1DL, between 1BL and 1RL, and between 1RL and 1AL or 1DL. Recombinant types 1AL – 1DL did not differ from the parental type for the C-banding pattern and was not considered. In the three genotypes, most if not all of 1BL – 1AL, 1BL – 1DL, and 1BL – 1RL metaphase I bonds were chiasmatic. 1RL – 1AL and 1RL – 1DL associations were scarce. Frequencies of one chiasma and two chiasmata for the arm combinations 1BL – 1AL plus 1BL – 1DL, 1BL – 1RL, and 1RL – 1AL plus 1RL – 1DL were estimated. Values decreased in the order ph1b, 5B-deficient, and ph2b hybrids.Key words: C-banding, chiasmata, homoeologues, anaphase I, ph genes.

scholarly journals Timing imbalance in the meiosis of the F1 hybrid Oryza sativa × O. australiensis

1961 ◽  
Vol 2 (3) ◽  
pp. 373-383 ◽  
Author(s):  
S. V. S. Shastry ◽  
D. R. Ranga Rao
Keyword(s):  
Oryza Sativa ◽  
Comparative Morphology ◽  
Meiotic Pairing ◽  
F1 Hybrid ◽  
Oryza Saliva ◽  
End To End ◽  
Primitive Member ◽  
Meiotic Cycle ◽  
Metaphase I

The meiosis in the F1 hybrid Oryza saliva × O. australiensis was studied. Contrary to the observations of Gopalakrishnan (1959), true allosyndetic bivalents were not found at metaphase I. The most frequent associations were non-chiasmatic, end-to-end pseudobivalents. Autosyndetic bivalents were recorded mostly in the complement belonging to O. sativa, which are distinguishable by their smallness and lighter staining. The meiotic cycle exhibits timing imbalance with earlier condensation, and possibly migration, of the univalents belonging to O. australiensis. The data on meiotic pairing in the F1 hybrid and the comparative morphology of O. sativa, O. officinalis and O. australiensis inicate that the last species is the most primitive member, having originated from the pre-Sativa and pre-Officinalis complex.

scholarly journals Morphology and Meiotic Behavior of Three Dendrobium Amphidiploids and Their Diploid Counterparts

HortScience ◽  
1993 ◽  
Vol 28 (9) ◽  
pp. 935-937 ◽  
Author(s):  
James McConnell ◽  
H. Kamemoto
Keyword(s):  
Small Chromosome ◽  
Chromosome Size ◽  
Meiotic Behavior ◽  
Preferential Pairing ◽  
Bivalent Formation ◽  
Metaphase I

Floral characteristics, meiotic behavior, and sporad formation were compared in three Dendrobium tetraploids (amphidiploids) and their diploid counterparts. Amphidiploid flowers were larger than those of diploids. Diploid meiotic behavior varied; mean configurations at Metaphase I ranged from 14.3 bivalents and 9.4 univalents to 18.9 bivalents and 0.2 univalents. In amphidiploids, nearly all cells had 38 bivalents. Sporad formation also varied; diploids had 36% to 70% tetrads and amphidiploids had 97% to 100% tetrads. Preferential pairing and small chromosome size may promote bivalent formation in amphidiploids.

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