Image analysis of C-banded chromosomes and pairing regionalization in wheat

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 1062-1067 ◽  
Author(s):  
Angeles Bernardo ◽  
Martin Montero ◽  
Angeles Cuadrado ◽  
Nicolás Jouve

C-banding and image analysis are used to characterize nine somatic chromosomes of wheat and to quantify a series of physical parameters (arm length, heterochromatic band intensity and position) in tetraploid Triticum turgidum and hexaploid T. aestivum wheat. The arm-by-arm meiotic association of the chromosomes at first meiotic metaphase is evaluated with respect to these parameters and genetic pairing regulators. The effect of the genetic factors is analyzed comparatively in homozygous lines or both normal and mutant lines (Ph1/Ph1, ph1a/ph1a, ph1b/ph1b, and ph1c/ph1c) and in aneuploids (ditelo-5BL and nulli-5B–tetra-5D). The pairing values were progressively reduced as follows: 'Chinese Spring' Ph1/Ph1 > 'Chinese Spring' dt-5BL > 'Chinese Spring' ph1a/ph1a > 'Chinese Spring' nulli-5B–tetra-5D > 'Chinese Spring' ph1b/ph1b > 'Cappelli' ph1c/ph1c. The results indicate that although a different contribution to overall pairing exists for each specific chromosome region, the differences in the genetic systems regulating pairing from line to line indiscriminately affected chiasma levels and did not lead to specific deviations in any line. The results seem to show that maintenance of chiasmata at first metaphase of meiosis depends on chromosome length and correlation is strong for the chance of double chiasmata. Moreover, there are indications that some C-bands, particularly in intercalary positions in chromosome arms 4AL, 2BL, 5BS, and 7BL, increase the frequency of chiasma at first metaphase. The pairing intensity in each specific chromosomal segment may be the product of an integrated action of chromosome length, the presence or absence of heterochromatin, and genetic factors.Key words: image analysis, heterochromatin, Triticum, C-banding, meiotic pairing.

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 814-819 ◽  
Author(s):  
S Rodríguez ◽  
B Maestra ◽  
E Perera ◽  
M Díez ◽  
T Naranjo

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 ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 873-882 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
P. G. Goicoechea ◽  
R. Giraldez

Meiotic pairing was studied at metaphase I in three different cv. Chinese Spring × rye hybrid combinations (5B deficient, 3D deficient, and normal ABDR) to establish the arm homoeology of wheat and rye chromosomes. The majority of individual wheat chromosomes and their arms, as well as the arms of chromosomes 1R and 5R, were identified by means of C-banding. The results on pairing relationships support the genome reallocation of chromosomes 4A and 4B. The short arms of wheat chromosomes belonging to homoeologous groups 1, 3, 5, and 6 and of chromosome pairs 4A–4D and 7A–7D showed full pairing homoeology as well as the long arms of wheat chromosomes of groups 1, 3, 6, and 7 and of chromosome pairs 4A–4D and 5B–5D. Chromosomes 2A, 2B, and 2D were homoeologous, but the homoeologies of their arms were not identified. Reduced homoeologies of the 4BL arm to 7AS and 7DS, of the 5AL arm to 4AL and 4DL, and of the 7BS arm to 5BL and 5DL were identified. Arms 4BL, 5AL, and 7BS are involved in a double translocation that arose during the evolution of common wheat. The homoeology relationships of chromosome arm 4BS were not identified since this arm seldom paired. The homoeologous pairing pattern between wheat chromosomes was characterized by a remarkable predominance of A–D associations, altered only by structural changes in groups 4 and 5. Chromosome arm 1RL showed full pairing homoeology to 1AL, 1BL, and 1DL, while 5RL was homoeologous to 5AL and partially homoeologous to 4AL and 4DL. It is concluded that 5RL carries a translocated segment from 4RL. Key words: homoeologous pairing, translocations, wheat evolution, C-banding.


2013 ◽  
Author(s):  
Krzysztof Nowakowski ◽  
Barbara Raba ◽  
Robert J. Tomczak ◽  
Piotr Boniecki ◽  
Sebastian Kujawa ◽  
...  

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 8-11
Author(s):  
H. S. Balyan ◽  
G. Fedak

Three hybrids of Triticum turgidum cv. Ma with Hordeum californicum × T. aestivum cv. Chinese Spring amphiploid were obtained at a frequency of 1.6% of the pollinated florets. Meiotic analysis of the hybrid plants revealed an average chiasma frequency per pollen mother cell ranging from 15.27 to 17.60. The lower than expected chromosome pairing in the hybrid plants was attributed to the suppression of pairing between homologous wheat chromosomes by pairing regulatory gene(s) in H. californicum.Key words: intergeneric hybrids, Hordeum californicum, Triticum turgidum, meiosis, chromosome pairing.


1985 ◽  
Vol 27 (6) ◽  
pp. 689-696 ◽  
Author(s):  
A. Fominaya ◽  
N. Jouve

The characterization of reciprocal interchanges between chromosomes of wheat in the progeny of the backcross ((T. aestivum H-53 × S. cereale) × T. aestivum H-53) using Feulgen and C-banding staining techniques has been attempted. The translocated chromosomes were studied in detail in three lines using monosomic analysis. In the F1 of the crosses between these lines and the 21 monosomic lines of 'Chinese Spring' a total of five interchanges were identified. Using a Giemsa C-banding procedure it was possible to confirm the identity of the interchange chromosome pairs that were previously identified by monosomic analysis. Moreover, a total of 12 new interchanges were characterized or identified. C-banding also facilitated the identification of the arms involved in translocations and permitted the quantitative analysis of each multivalent in multiple interchange heterozygotes. The comparative availability of Feulgen and C-banding in studies of cytogenetic structure in wheat is discussed.Key words: C-banding, meiosis, heterochromatin, translocations, wheat, Triticum.


2000 ◽  
Vol 663 ◽  
Author(s):  
M. Kemppainen ◽  
E. Oila ◽  
M. Siitari-Kauppi ◽  
P. Sardini ◽  
K-H. Hellmuth

ABSTRACTRadioelement migration within a rock matrix under natural long-term conditions is a complex process controlled by various parameters. Pure physical parameters such as porosity, hydraulic conductivity and diffusivity are usually sufficient to describe transport in well-defined laboratory systems. In natural rock matrices transport is influenced by physical pore properties such as pore size distribution, connectivity, tortuosity, constrictivity and petrological and chemical nature and charge on the fluid-rock interface. The overall characterization of heterogeneous rock structures is needed for the accurate heterogeneous diffusion modeling.Here we describe a method for the detection of μ-particles from uranium in cm-scale rock samples based on the analysis of the tracks formed in organic polymer, CR-39. On the other hand the uranium tracks were compared with the migration pathways and porosity distribution produced with the 14C-polymethylmethacrylate impregnation method (14C-PMMA). For analyzing mineral specific uranium occurrence and porosities the staining methods were used to produce the mineral map of the rock sample. Digital image analysis techniques were applied to the different cm-scale pictures of rock samples. Scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS) were performed in order both to study the pore apertures of grain boundaries and fissures in greater detail and to detect the uranium phases.The high uranium content was found to be congruent with the porous mineral phases; altered plagioclase and biotite grains, and the intra- and intergranular fissures detected with the 14C-PMMA technique. Plenty of microfractures transsecting potassium feldspar and quartz grains were filled with calcite together with precipitated uranium.


Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 689-696 ◽  
Author(s):  
A Fominaya ◽  
S. Molnar ◽  
G. Fedak ◽  
K. C. Armstrong ◽  
N.-S. Kim ◽  
...  

Diagnostic markers for eight Thinopyrum distichum addition chromosomes in Triticum turgidum were established using C-banding, in situ hybridization, and restriction fragment length polymorphism analysis. The C-band karyotype conclusively identified individual Th. distichum chromosomes and distinguished them from chromosomes of T. turgidum. Also, TaqI and BamHI restriction fragments containing 5S and 18S–5.8S–26S rRNA sequences were identified as positive markers specific to Th. distichum chromosomes. Simultaneous fluorescence in situ hybridization showed both 5S and 18S–5.8S–26S ribosomal RNA genes to be located on chromosome IV. Thinopyrum distichum chromosome VII carried only a 18S–5.8S–26S rRNA locus and chromosome pair II carried only a 5S rRNA locus. The arrangement of these loci on Th. distichum chromosome IV was different from that on wheat chromosome pair 1B. Two other unidentified Th. distichum chromosome pairs also carried 5S rRNA loci. The homoeologous relationship between Th. distichum chromosomes IV and VII and chromosomes of other members of the Triticeae was discussed by comparing results obtained using these physical and molecular markers.Key words: Triticum turgidum, homoeologous relationship, Triticeae, addition lines, NOR.


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