HOMOEOLOGY BETWEEN AGROPYRON ELONGATUM CHROMOSOMES AND TRITICUM AESTIVUM CHROMOSOMES

1980 ◽  
Vol 22 (2) ◽  
pp. 237-259 ◽  
Author(s):  
J. Dvořák

Genetic compensation of Agropyron chromosomes for wheat chromosomes in the male gametophyte and compensation of Agropyron chromosomes for wheat chromosomes in disomic substitutions were used to investigate relationships between the chromosomes of Agropyron elongatum (Host.) P.B. (2n = 2x = 14) and Triticum aestivum L. emend. Thell. (2n = 6x = 42). Gametophytic compensation indicated that A. elongatum chromosomes I, II, III, IV, and VII were related to wheat chromosomes of homoeologous groups 1, 7, 4, 3, and 6, respectively, and were designated 1E, 7E, 4E, 3E, and 6E. Chromosomes V and VI appeared to be related to homoeologous group 2. Other analyses showed that chromosomes V and VI originated from arm exchanges between chromosome 2E and other Agropyron chromosomes. An unaltered disome of Agropyron chromosome 2E was added to the wheat chromosome complement. In the disomic substitutions Agropyron chromosomes 1E, 6E, and 7E compensated for all three wheat homoeologues of the respective homoeologous groups. Chromosome 4E fully compensated for chromosome 4D but only partially for chromosomes 4A and 4B. Chromosomes V and VI compensated poorly or not at all for wheat chromosomes of group 2.

1979 ◽  
Vol 21 (2) ◽  
pp. 243-254 ◽  
Author(s):  
J. Dvořák

Ten telocentric chromosomes of diploid Agropyron elongatum (Host.) P.B. (2n = 14) were added to the chromosome complement of Triticum aestivum L. emend. Thell. The ditelosomic additions were crossed with Triticum speltoides (Tausch) Gren. ex Richter, and in the tetraploid hybrids the pairing frequencies of the telosomes were determined, expressed as percent of PMC's in which a telosome paired at metaphase I. All Agropyron telosomes paired with Triticum chromosomes. The pairing frequencies ranged from 4.4% to 41.2% of the PMC's, it is concluded that none of the ten Agropyron chromosome arms has a homologous partner among the four Triticum genomes involved. The pairing frequencies did not correlate with the lengths of the telosomes. Pairing of the Agropyron telosomes in these tetraploid hybrids approximated the chromosome pairing that occurred in a diploid hybrid T. tauschii (Coss.) Schmal. (the donor of the D genome of T. aestivum) × A. elongatum.


1981 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Y. Yasumuro ◽  
R. Morris ◽  
D. C. Sharma ◽  
J. W. Schmidt

A study was initiated to transfer genes for stem- and leaf-rust resistance from a chromosome (designated 6Ag) of Agropyron elongatum (Host) Beauv to a homoeologous chromosome (6D) of wheat (Triticum aestivum L. aestivum group) by inducing pairing between 6Ag and 6D in the absence of the Ph gene on wheat chromosome 5B. Plants monosomic for SB, 6D and 6Ag were crossed with Chinese Spring nullisomic-5B tetrasomic-5D or with Chinese Spring monosomic or trisomic for SB with an induced mutation, phlb, of the Ph locus. Tests of 282 offspring in the seedling stage for reaction to the stem rust pathogen, Puccinia graminis Pers. f. sp. tritici Eriks. &E. Henn. race 56 or 15B-2, were used to identify 70 plants with 6Ag, which was transmitted through 25% of the female gametes. Meiotic observations on 51 of these plants indicated that six were monosomic for 6D and 6Ag, but lacked an entire 5B or had 5B with the phlb mutation. The frequency of metaphase I cells with pairing between 6D and 6Ag averaged 4.94% in three plants that were nullisomic for 5B and 2.48% in two plants that had a single dose of 5B with the phlb mutation.


Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 365-366 ◽  
Author(s):  
G. C. Eizenga

Twelve lines of wheat (Triticum aestivum L.) were originally identified as having a segment of Agropyron elongatum chromatin carrying a gene for resistance to leaf rust (Puccinia recondita tritici) transferred to wheat chromosome 7D. By studying the chromosome pairing of one of these lines, transfer no. 12, with telosomes 7AL, 7AS, 7BL, 7BS, 7DL, 7DS, and 7AgS, it was determined that the Agropyron chromatin was carried on the long arm of wheat chromosome 7A rather than 7D. This determination was confirmed by acetocarmine–N-banding. Key words: Triticum aestivum, Agropyron elongatum, transfer lines, Puccinia recondita tritici, telosomic analysis.


1977 ◽  
Vol 19 (1) ◽  
pp. 75-79 ◽  
Author(s):  
D. R. Knott ◽  
J. Dvořák ◽  
J. S. Nanda

A stem rust resistant wheat-Agropyron derivative obtained from Dr. F. X. Laubscher was crossed and backcrossed to Triticum aestivum L. cv. Marquis to determine the inheritance of its resistance to stem rust. Resistance proved to be carried on an Agropyron chromosome. A substitution line was obtained in which the Agropyron chromosome had replaced wheat chromosome 7D. The Agropyron chromosome compensates well for 7D in both plants and gametes and must, therefore, be homoeologous with the chromosomes of group 7. It is homologous with chromosome 7el1, the Agropyron chromosome carrying leaf rust resistance in Agrus, and it is, therefore, designated 7el2. Like 7el1 it carries a gene that results in a high level of yellow pigment in the flour. The frequent occurrence of genes for rust resistance on Agropyron chromosomes of homoeologous group 7 suggests that they may be related by descent.


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.


Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 525-529 ◽  
Author(s):  
V. D. Keppenne ◽  
P. S. Baenziger

The blue aleurone trait has been suggested as a useful genetic marker in wheat (Triticum aestivum L.). However, little information is available on its transmission in diverse backgrounds and on its use to identify hybrid seed. UC66049, a hexaploid spring wheat with a spontaneous translocation that included the gene for the blue aleurone trait (Ba) from Agropyron elongatum (Host) P.B. (synonymous with Elytrigia pontica (Podp.) Holub), was crossed to seven wheat cultivars to test the transmission of the trait. UC66049 was crossed to male-sterile red wheat lines to evaluate the blue aleurone trait as a marker for confirming hybridity. Ba segregated as a dominant gene that was transmitted normally through the male and female gametes. For 6 of 7 crosses with diverse pedigrees, we experienced problems with misclassification of the aleurone color in the F2 seed generation, determined by the F3 seed family data. The blue aleurone trait is a good genetic marker; however, progeny testing may be needed to confirm the F2 genotypes in some environments or genetic backgrounds. Moreover, Ba is useful in determining the amount of controlled hybridity as opposed to self-fertility and (or) outcrossing in genetic male-sterile wheat lines. The use of Ba to confirm doubled haploidy was proposed.Key words: Agropyron elongatum, seed color, genetics, Triticum aestivum, Elytrigia pontica.


1984 ◽  
Vol 26 (2) ◽  
pp. 128-132 ◽  
Author(s):  
J. Dvořák ◽  
K. C. Chen

Gametophytic compensation of the Elytrigia elongata chromosome 2E for wheat chromosomes was assessed by determining the vigour of the gametophytes having the Elytrigia chromosome substituted for a wheat chromosome relative to normal wheat gametophytes. These tests showed that chromosome 2E compensated in the gametophyte for wheat chromosomes 2B and 2D, but not for 2A. The Elytrigia chromosome was also occasionally transmitted by male gametophytes when substituted for chromosomes 3A, 4B, and 6B. Chromosome 2E was then substituted for chromosomes 2A, 2B, and 2D. In each disomic substitution the Elytrigia chromosome showed good compensation for the nullisomy of the respective wheat chromosome, as indicated by normal vigor and fertility of the plants. These data confirmed that E. elongata chromosome 2E is phylogenetically related to wheat chromosomes of homoeologous group 2.Key words: Triticum, Elytrigia, phylogeny, wheat.


Genome ◽  
2011 ◽  
Vol 54 (10) ◽  
pp. 836-844 ◽  
Author(s):  
Cheng Liu ◽  
Lili Qi ◽  
Wenxuan Liu ◽  
Wanchun Zhao ◽  
Jamie Wilson ◽  
...  

Dasypyrum villosum (L.) Candargy, a wild relative of bread wheat ( Triticum aestivum L.), is the source of many agronomically important genes for wheat improvement. Production of compensating Robertsonian translocations (cRobTs), consisting of D. villosum chromosome arms translocated to homoeologous wheat chromosome arms, is one of the initial steps in exploiting this variation. The cRobTs for D. villosum chromosomes 1V, 4V, and 6V have been reported previously. Here we report attempted cRobTs for wheat – D. villosum chromosome combinations 2D/2V, 3D/3V, 5D/5V, and 7D/7V. The cRobTs for all D. villosum chromosomes were recovered except for the 2VS and 5VL arms. As was the case with the 6D/6V combination, no cRobTs involving 2D/2V chromosomes were recovered; instead, cRobT T2BS·2VL involving a nontargeted chromosome was recovered. All cRobTs are fertile, although the level of spike fertility and hundred kernel weight (HKW) varied among the lines. The set of cRobTs involving 12 of the 14 D. villosum chromosomes will be useful in wheat improvement programs. In fact, among the already reported cRobTs, T6AL·6VS carrying the Pm21 gene is deployed in agriculture and many useful genes have been reported on other cRobTs including resistance to stem rust race UG99 on T6AS·6VL.


1967 ◽  
Vol 10 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Roy Johnson ◽  
Gordon Kimber

1. Complex hybrids were produced having twenty-nine chromosomes, consisting of one telocentric and twenty complete chromosomes of T. aestivum (2n = 6x = 42), seven complete chromosomes of Ae. speltoides (2n = 2x = 14) and one telocentric chromosome derived from A. elongatum (2n = 10x = 70). The presence of the Ae. speltoides genome permitted pairing between homoeologous chromosomes at meiosis and the behaviour of the two telocentric chromosomes was observed.2. The A. elongatum chromosome was seen to pair with chromosomes homoeologous to those of group 6. There was no evidence that it paired with chromosomes of any other group.3. When the A. elongatum telocentric and those of 6A and 6D occurred in the same configuration it was evident that the telocentrics 6A and 6D were for corresponding chromosome arms, and the A. elongatum telocentric for the opposite arm.4. The average rate of pairing was much lower for the A. elongatum telocentric than for wheat telocentrics. Previous studies had indicated very good genetic compensation of the A. elongatum chromosome for chromosomes 6A and 6D. It was therefore indicated that genetic equivalence and pairing affinity were not closely related in this case. Some implications of this are discussed.


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