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.

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.

CHROMOSOME PAIRING IN TWO INTERSPECIFIC HYBRIDS OF TRIFOLIUM

1970 ◽  
Vol 12 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Chi-Chang Chen ◽  
Pryce B. Gibson
Keyword(s):  
Phylogenetic Relationship ◽  
Chromosome Pairing ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Triploid Hybrid ◽  
Close Phylogenetic Relationship ◽  
Metaphase I

Both Trifolium repens (2n = 32) and T. nigrescens (2n = 16) formed bivalents during meiosis. However, their triploid hybrid showed an average of 4.27 trivalents per microsporocyte at metaphase I. The frequency of trivalents in the hybrid between T. nigrescens and autotetraploid T. occidentale (2n = 32) was 5.69. The data are interpreted to indicate: (1) a possible autotetraploid origin of T. repens; and (2) a close phylogenetic relationship among T. repens, T. nigrescens and T. occidentale.

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.

A TENTATIVE IDENTIFICATION OF CHROMOSOMES PRESENT IN TETRAPLOID TRITICALE BASED ON HETEROCHROMATIC BANDING PATTERNS

1978 ◽  
Vol 20 (2) ◽  
pp. 199-204 ◽  
Author(s):  
J. P. Gustafson ◽  
K. D. Krolow
Keyword(s):  
Secale Cereale ◽  
Banding Pattern ◽  
Triticum Turgidum ◽  
Staining Technique ◽  
Wheat Genome ◽  
Banding Patterns ◽  
Tentative Identification ◽  
C Banding ◽  
B Genome ◽  
Secale Cereale L

Three tetraploid triticales were analysed by C-banding techniques in order to establish their chromosome constitutions. All three tetraploid triticales contained seven rye chromosomes with the banding pattern of Secale cereale L. A mixture of A- and B-genome chromosomes from Triticum turgidum L. constituted the wheat genome present in the tetraploid triticales. Triticale Trc 4x3 contained 1A, 2B, 3A, 4A, 5B, 6A, and 7B. Triticale Trc 4x2 contained 1A, 2B, 3B, 4B, 5B, 6A, and 7B, while triticale Trc 4x5 contained 1A, 2B, 3B, 4A, 5A, 6A, and 7B. The reliability of the staining technique is subject to errors in identification, which are discussed.

Chromosome structural changes and their role in the evolution of tetraploid wheats

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 257-261 ◽  
Author(s):  
Kaz. Noda ◽  
Ge Koulin
Keyword(s):  
Key Words ◽  
Structural Changes ◽  
Triticum Dicoccoides ◽  
Aegilops Speltoides ◽  
Banding Patterns ◽  
Tetraploid Wheats ◽  
B Genome ◽  
Triticum Boeoticum

The possibility that chromosomal interchanges present in the Timopheevi group (AAGG) are responsible for the differentiation of two different groups of tetraploid wheats, the Emmer group (AABB) and the Timopheevi (AAGG) group, has been examined. Chromosomes of Triticum dicoccoides (2n = 28, AABB) and six interchange types of the Timopheevi group (2n = 28, AAGG) were studied by N-banding. The banding patterns of the G genome were distinct from those of the B genome. The banding patterns of the G genome chromosomes of the interchange types were similar to the basic banding patterns of the G genome except those of interchanged chromosomes. No intermediate banding patterns between the B and G genomes were observed. These interchanges might have occurred after establishment of the basic karyotype of the G genome and would not be related to the differentiation of AABB and AAGG from a progenitor tetraploid, such as amphidiploid (AASS) between Aegilops speltoides (SS) and Triticum boeoticum (AA).Key words: tetraploid wheats, N-banding, interchange.

CHROMOSOME PAIRING IN HEXAPLOID HYBRIDS FROM BROMUS ERECTUS (2n = 28) × B. INERMIS (2n = 56)

1973 ◽  
Vol 15 (3) ◽  
pp. 427-436 ◽  
Author(s):  
K. C. Armstrong
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Meiotic Chromosome ◽  
The Other ◽  
Meiotic Chromosome Pairing ◽  
Hybrid Plants ◽  
Quadrivalent Frequency ◽  
Bromus Erectus ◽  
Metaphase I

Meiotic chromosome pairing was studied at metaphase I of B. erectus (2n = 28), B. inermis (2n = 56) and interspecific hybrids from B. erectus × B. inermis (2n = 42). The B. erectus material averaged 2.08 IV + 0.11 III + 9.51 II + 0.35 I and B. inermis 0.05 VIII + 0.06 VI + 0.02 V + 2.25 IV + 0.11 III + 22.95 II + 0.25 I. The hybrid plants (2n = 42) averaged 0.18 VI + 1.90 IV + 0.19 III + 16.10 II + 0.39 I and one hybrid with 2n = 41 averaged 0.08 VI + 0.02 V + 0.95 IV + 0.50 III + 17.42 II + 0.72 I. Karyotype evidence supported the conclusion that B. erectus was an autotetraploid. The karyotype contains four large satellites and four subterminal chromosomes but the other four groups of four are median, with one group possibly a submedian. Since chromosome pairing in the hybrids was complete and the quadrivalent frequency in the parents and hybrids was similar, it was concluded that the genomic formula of B. erectus, B. inermis, and the hybrid was AAAA, AAAABBBB, and AAAABB, respectively.

Amphidiploids of perennial Triticeae. I. Synthetic Thinopyrum species and their hybrids

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 951-956 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Gene Flow ◽  
Chromosome Pairing ◽  
Colchicine Treatment ◽  
Meiotic Pairing ◽  
Pseudoroegneria Spicata ◽  
Genomic Relationships ◽  
Thinopyrum Elongatum ◽  
Metaphase I

Amphiploids of the hybrid Thinopyrum elongatum (Host) D.R. Dewey (2n = 2x = 14; JeJe) × Pseudoroegneria spicata (Pursh) A. Löve (2n = 2x = 14; SS) were obtained by the colchicine treatment of regenerants from inflorescence culture. Meiotic pairings in the JJSS amphiploids averaged 2.90 I + 4.44 rod II + 7.50 ring II + 0.14 III + 0.20 IV at metaphase I but had 13.38 ring II + 0.30 IV at diakinesis. This amphidiploid was crossed with that of T. bessarabicum (Savul. &Rayss) A. Löve (2n = 2x = 14; JbJb) × T. elongatum and the latter was also crossed with T. scirpeum (K. Presl) D.R. Dewey (2n = 4x = 28; JeJeJeJe) to obtain JbJeJeS and JeJeJeJb hybrids, respectively. The former hybrid had a metaphase I pairing pattern of 7.82 I + 4.33 rod II + 2.76 ring II + 1.51 III + 0.35 IV. The latter hybrid had 3.04 I + 4.05 rod II + 4.31 ring II + 1.26 III + 1.08 IV. These meiotic pairing data are in agreement with the genomic relationships based on the diploid hybrids involving these genomes. Fertility of the hybrid between T. scirpeum and the amphiploid of T. bessarabicum × T. elongatum suggested that their genomes were similar and balanced and that gene flow could occur between the JJ diploids and the JJJJ tetraploid.Key words: hybrid, amphidiploid, genome, isozyme, chromosome pairing, Triticeae, Thinopyrum.

Chromosome structure of Triticum timopheevii relative to T. turgidum

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 923-930 ◽  
Author(s):  
S Rodríguez ◽  
E Perera ◽  
B Maestra ◽  
M Díez ◽  
T Naranjo
Keyword(s):  
Chromosome Structure ◽  
Triticum Turgidum ◽  
Chromosomal Rearrangements ◽  
In Situ Hybridisation ◽  
Triticum Timopheevii ◽  
C Banding ◽  
Genomic In Situ Hybridisation ◽  
Banding Analysis ◽  
Wild Accessions ◽  
Species Specific

The chromosome structure of four different wild populations and a cultivated line of Triticum timopheevii (2n = 28, AtAtGG) relative to Triticum turgidum (2n = 28, AABB) was studied, using genomic in situ hybridisation (GISH) and C-banding analysis of meiotic configurations in interspecific hybrids. Two wild accessions and the cultivated line showed the standard C-banding karyotype. The other two accessions are homozygous for translocation 5At/3G and translocations 1G/2G and 5G/6G. GISH analysis revealed that all the T. timopheevii accessions carry intergenome translocations 6At/1G and 1G/4G and identified the position of the breakpoint in translocation 5At/3G. C-banding analysis of pairing at metaphase I in the hybrids with T. turgidum provides evidence that four species-specific translocations (6AtS/1GS, 1GS/4GS, 4GS/4AtL, and 4AtL/3AtL) exist in T. timopheevii, and that T. timopheevii and T. turgidum differ in the pericentric inversion of chromosome 4A. Bridge plus acentric fragment configurations involving 4AL and 4AtL were identified in cells at anaphase I. This result suggests that the paracentric inversion of 4AL from T. turgidum does not exist in T. timopheevii. Both tetraploid species have undergone independent and distinct evolutionary chromosomal rearrangements. The position, intercalary or subdistal, of the breakpoints in species-specific translocations and inversions contrasts with the position, at or close to the centromere, of intraspecific translocations. Different mechanisms for intraspecific and species-specific chromosome rearrangements are suggested.Key words: Triticum timopheevii, chromosome pairing, translocation, evolution, C-banding, GISH.

Meiotic pairing in new hybrids of Hordeum procerum (6x) with H. parodii (6x) and Elymus virginicus (4x)

1986 ◽  
Vol 28 (3) ◽  
pp. 416-419 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrid ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Metaphase I

Hybrids of Hordeum procerum were readily produced with H. parodii (7.9%) and Elymus virginicus (14.3%). The average meiotic pairing per cell in the interspecific hybrid between H. procerum and H. parodii was 14.56 I + 12.19 II + 1.04 III, which indicated that the species have two genomes in common. In the hybrid between H. procerum and E. virginicus the average metaphase I configuration was 20.35 I + 6.86 II + 0.31 III indicating one common genome. Keywords: interspecific, intergeneric hybrids, chromosome pairing, Hordeum, Elymus.

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