COMPENSATED MONOSOMIC 5B-TRISOMIC 5A PLANTS IN TETRAPLOID WHEAT

1972 ◽  
Vol 14 (3) ◽  
pp. 463-475 ◽  
Author(s):  
T. Mello-Sampayo

Tetraploid wheat plants monosomic 5B-trisomic 5A were obtained by crossing nullisomic 5B-tetrasomic 5A plants of Triticum aestivum with T. durum and backcrossing five times with T. durum. These plants were found to carry a translocated 5A-5D chromosome. By self-pollination they originated plants carrying both a 5A-5D and 5B-5D translocated chromosome. In the latter the break point was located distally to the pairing suppressor gene. The translocations must have occurred by homoeologous pairing and recombination in the long arm of chromosomes of the group 5. F1 hybrids of monosomic 5B-trisomic 5A plants with rye and Aegilops sharonensis showed high homologous pairing when 5B was absent. Pairing promotion associated with the terminal segment of the long arm of 5D attached to the 5B-5D chromosome end was detected. It was suggested that the long arm of chromosomes of the homoeologous group 5 of wheat might carry two separate loci with genes for antagonistic effects on the pairing of chromosomes.

Genome ◽  
2006 ◽  
Vol 49 (7) ◽  
pp. 729-734 ◽  
Author(s):  
R C Leach ◽  
I S Dundas ◽  
A Houben

The physical length of the rye segment of a 4BS.4BL–5RL translocation derived from the Cornell Wheat Selection 82a1-2-4-7 in a Triticum aestivum 'Chinese Spring' background was measured using genomic in situ hybridization (GISH) and found to be 16% of the long arm. The size of this translocation was similar to previously published GISH measurements of another 4BS.4BL–5RL translocation in a Triticum aestivum 'Viking' wheat background. Molecular maps of both 4BS.4BL–5RL translocations for 2 different wheat backgrounds were developed using RFLP analysis. The locations of the translocation breakpoints of the 2 4BS.4BL–5RL translocations were similar even though they arose in different populations. This suggests a unique property of the region at or near the translocation breakpoint that could be associated with their similarity and spontaneous formation. These segments of rye chromosome 5 also contain a gene for copper efficiency that improves the wheat's ability to cope with low-copper soils. Genetic markers in these maps can also be used to screen for copper efficiency in bread wheat lines derived from the Cornell Wheat Selection 82a1 2-4-7.Key words: Triticum aestivum, wheat–rye translocation, homoeologous group 4, homoeologous group 5, GISH, comparative map, copper efficiency, hairy peduncle.


2008 ◽  
Vol 44 (No. 1) ◽  
pp. 22-29 ◽  
Author(s):  
K. Pánková ◽  
Z. Milec ◽  
M. Leverington-Waite ◽  
S. Chebotar ◽  
J.W. Snape

Several sets of wheat inter-varietal chromosome substitution lines (SLs) have been produced over the last fifty years at the CRI (formerly RICP) in Prague-Ruzyně, based on cytogenetic manipulations using aneuploids. Lines with defined genes have been obtained which significantly influence growth habit and flowering time and these have been used particularly in the study of the genetics and physiology of flowering. The sets of lines include substitutions of homoeologous group 5 chromosomes carrying Vrn genes that control vernalisation response, homoeologous group 2 chromosomes with Ppd genes controlling photoperiodic sensitivity, and some other substitutions, particularly those with chromosome 3B of the Czech alternative variety Česká Přesívka where a novel flowering time effect was located. Although the phenotypic and cytological analysis of substitution lines has been continually carried out during backcrossing generations, only the use of molecular markers can allow an unambiguous characterization to verify that substitutions are correct and complete. This analysis has allowed incorrect substitutions or partial substitutions to be identified and discarded. This paper summarizes the results of recent molecular checks of the substitution line collections at CRI.


1982 ◽  
Vol 24 (6) ◽  
pp. 715-719 ◽  
Author(s):  
E. R. Sears

An X-ray-induced mutation in common wheat (Triticum aestivum L.), designated ph2, conditions an intermediate level of homoeologous chromosome pairing in hybrids with Triticum kotschyi var. variabilis. The number of chromosomes paired averaged 9.2 per sporocyte, compared with 2.0 in the control and 27.9 in the same hybrid involving ph1b, an apparent deficiency for Ph1 obtained in the same mutation experiment. The ph2 mutation is located on chromosome 3D and is believed to be a deficiency for a terminal segment of the short arm that includes the locus of Ph2, a minor suppressor of homoeologous pairing. Although no pairing of the ph2-carrying chromosome with telosome 3DS was observed, the mutation is clearly not a deficiency for the entire arm. It has little effect on pairing in wheat itself. Male transmission of the mutation is approximately normal, and fertility, while reduced, is sufficient for easy maintenance of the homozygous line.


Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 658-663
Author(s):  
Carla Ceoloni ◽  
Moshe Feldman

Two lines of common wheat cv. Chinese Spring carrying mutant alleles for the Ph2 homoeologous pairing-suppressor gene on chromosome arm 3DS promoting homoeologous pairing in wheat interspecific and intergeneric hybrids have been tested for their mitotic sensitivity to colchicine. Both the ph2a mutation, which corresponds to a fairly long deletion of 3DS, and ph2b, which is either an intragenic change or a very small deletion, as well as the ph2a/ph2b heteroallelic combination and the deficiency for the entire 3DS arm (ditelo 3DL), conditioned a significantly lower sensitivity to colchicine than that determined by the wild-type allele Ph2 (euploid and ditelo 3DS). Observation of both metaphase and anaphse root-tip cell populations, treated with various colchicine concentrations, provided similar results. The degree of spindle disruption in 2 × 10−4 M colchicine, as measured by the percentage of fully affected metaphases (C type), was significantly reduced in ph2 and Ph2− genotypes and, consequently, a larger proportion of cells could proceed toward anaphase and also had a regular segregation pattern at this stage. The differential sensitivity of ph2 genotypes to colchicine is in the opposite direction to that previously found for ph1 genotypes, lacking the homoeologous pairing suppressor on chromosome arm 5BL. The ph2 mutation, while promoting homoeologous pairing as ph1 does, decreases spindle sensitivity to colchicine with respect to the wild-type (ph2) allele rather than increasing it, as ph1 does. The observed alteration of spindle sensitivity to colchicine that mutants for structurally unrelated but functionally related genes (Ph1 and Ph2) condition is interpreted as a highly probable coincidence in their cellular target. It is assumed therefore that these loci affect the equilibrium between tubulin and microtubules. Through this effect they presumably determine chromosome positioning in somatic and premeiotic stages, leading to different pairing patterns at meiosis. Key words: Triticum aestivum, tubulin, pairing suppressors, somatic association.


1987 ◽  
Vol 50 (2) ◽  
pp. 91-97 ◽  
Author(s):  
B. P. Forster ◽  
S. M. Reader ◽  
S. A. Forsyth ◽  
R. M. D. Koebner ◽  
T. E. Miller ◽  
...  

SummarySix wheat/Agropyron intermedium addition lines are described on the basis of their phenotype and biochemical markers. An assessment of homoeology of each addition chromosome is made. Chromosome morphology, plant phenotype, isozyme and protein studies are compared with similar data for other wheat/alien addition lines and other members of the Triticeae. These comparisons give consistent results and it is concluded that addition lines L1, L2, L3, L4, L5 and L7 carry Agropyron chromosomes of homoeologous groups 7, 3, 1, 4, 5 and 6 respectively. This agrees with previously published work with one exception: the L5 chromosome belongs to homoeologous group 5 and not group 2 as proposed by Figueiras et al. (1986).


2008 ◽  
Vol 21 (1) ◽  
pp. 1-11
Author(s):  
Prem P. Jauhar ◽  
Hamidur Rahman ◽  
Marepalli B. Rao
Keyword(s):  

1975 ◽  
Vol 50 (4) ◽  
pp. 283-289 ◽  
Author(s):  
HITOSHI ASAMI ◽  
TAKIKO SHIMADA ◽  
NOBUMICHI INOMATA ◽  
MASASUKE OKAMOTO

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 519-524 ◽  
Author(s):  
N. A. Tuleen ◽  
G. E. Hart

Isozyme markers were used to develop Triticum aestivum cv. Chinese Spring–Elytrigia elongata (= Agropyron elongatum, 2n = 14, genome E) disomic 3E and 5E addition lines. Subsequently, all possible lines containing 3E and 5E substituted for wheat homoeologues and several 3E and 5E ditelosomic addition and substitution lines were developed. Plants containing chromosome 3E substituted for wheat chromosomes of homoeologous group 3 are similar to 'Chinese Spring' in vigor and fertility while plants containing 3EL substituted for chromosomes of group 3 are less fertile than 'Chinese Spring'. This indicates that both arms of 3E are involved in sporophytic compensation. Plants containing chromosome 5E substituted for wheat chromosomes of homoeologous group 5 are as vigorous but less fertile than 'Chinese Spring'. 5EL (5A) and 5EL (5B) plants are lower in fertility than 5E (5A) and 5E (5B) plants, indicating that both arms of 5E are involved in sporophytic compensation. 5E (5D) and 5EL (5D) plants are similar in fertility. Male gametophytes in which 3E or 5E replaces a wheat homoeologue function at a lower rate than normal gametes.Key words: wheat, Triticum, Elytrigia elongata, alien chromosome addition lines.


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