THE TRANSFER OF GENE SR6 FROM CHROMOSOME 2D TO AN A OR B GENOME CHROMOSOME IN WHEAT (TRITICUM AESTIVUM)

1981 ◽  
Vol 23 (4) ◽  
pp. 655-669 ◽  
Author(s):  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Triticum Turgidum ◽  
Position Effect ◽  
Triticum Aestivum L ◽  
B Chromosome ◽  
Genome Chromosome ◽  
B Genome ◽  
Dosage Effects ◽  
Third Line

A procedure was carried out to transfer to an A or B chromosome of wheat (Triticum aestivum L.), a segment of chromosome 2D carrying the gene Sr6 for resistance to stem rust (Puccinia graminis tritici Eriks. and Henn.). The objectives were to make Sr6 available for breeding in durum wheat (Triticum turgidum L.) and to study dosage effects with Sr6. Plants were produced that had 14 pairs of chromosomes (the A and B genomes) plus an added chromosome 2D carrying Sr6, either as a whole chromosome or as an isosome or telosome. Seeds from these plants were irradiated with thermal neutrons and the M1 progeny were used as male parents in crosses with the durum cultivar Kubanka. Progeny that carried Sr6 and were resistant to stem rust were examined cytologically for the presence of translocations. Five translocations were obtained and then transferred to the hexaploid level by backcrossing. Homozygous lines were produced and four were analyzed in crosses with the Chinese Spring monosomics. In two of them the segment of the A or B genome chromosome had apparently been lost as a result of crossing over. In a third line the translocation involved 2D and its homoeologue 2A. In the final line it appeared that a segment of 2D had been inserted into chromosome 7B. When the chromosome carrying this translocation was transferred to the hexaploid level a position effect occurred that affected the expression of Sr6.

The analysis of meiosis of the B genome in common wheat

1985 ◽  
Vol 27 (1) ◽  
pp. 17-22 ◽  
Author(s):  
N. Jouve ◽  
J. M. Gonzalez ◽  
A. Fominaya ◽  
E. Ferrer
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Triticum Aestivum L ◽  
Genome Chromosome ◽  
Meiotic Analysis ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
B Genome ◽  
Whole Genomes ◽  
Chromosome Arm

Two intervarietal hybrids of common wheat, Triticum aestivum L., are meiotically analyzed using the C-banding staining method. The C-banding pattern of nine meiotic chromosomes (4A, 7A, and the seven of the B genome) permitted their unequivocal recognition at first metaphase plates. The pairing frequency of each B-genome chromosome arm was scored. Data on the pairing frequency of the arms, separately considered, are applied to calculate expected pairing of whole chromosomes and whole genomes. The application of mathematical models to predict the genome pairing using either equal or different frequencies per chromosome arm is discussed.Key words: meiotic analysis, Triticum aestivum L., C-banding.

The inheritance of resistance to stem rust in 'K253', a hexaploid wheat with resistance from the tetraploid 'C.I. 7778'

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 854-856
Author(s):  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Dominant Gene ◽  
Tetraploid Wheat ◽  
Recessive Gene ◽  
Triticum Aestivum L ◽  
Puccinia Graminis ◽  
Moderate Resistance

The inheritance of stem rust (Puccinia graminis f. sp. tritici Eriks. and Henn.) resistance was studied in 'K253', a hexaploid wheat (Triticum aestivum L.) with resistance derived from a tetraploid wheat (T. turgidum L.). The studies indicated that 'K253' carries one dominant gene for good resistance to races 29 and 56 (probably Sr9e) and one recessive gene for moderate resistance to race 15B-1. In addition, some plants apparently carry a recessive gene for moderate resistance to race 56. Four different types of hexaploid near-isogenic lines were produced. One carried Sr9e and another the gene for moderate resistance to race 15B-1. Two carried genes that had not been identified in the genetic studies, including one that was apparently not derived from K253.Key words: stem rust resistance, Puccinia graminis tritici, wheat, Triticum aestivum, Triticum turgidum.

Histological studies on host-cell necrosis conditioned by the Sr6 gene for resistance in wheat to stem rust

1977 ◽  
Vol 55 (11) ◽  
pp. 1445-1452 ◽  
Author(s):  
D. J. Samborski ◽  
W. K. Kim ◽  
R. Rohringer ◽  
N. K. Howes ◽  
R. J. Baker
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Fungal Growth ◽  
Triticum Aestivum L ◽  
Host Cells ◽  
Puccinia Graminis ◽  
Near Isogenic Lines ◽  
Cell Necrosis ◽  
Calcofluor White ◽  
Histological Studies

Seedlings of resistant (Sr6) and susceptible (sr6) near-isogenic lines of wheat (Triticum aestivum L.) were inoculated with a race of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) that was avirulent on the line with Sr6 and they were kept at 19, 25, 26, and 27 °C. Fluorescence microscopy was used to detect autofluorescing necrotic host cells and rust colonies after these were stained with a fiuorochrome (Calcofluor White M2R New).In leaves containing the Sr6 gene, a smaller percentage of colonies grown at 25 °C had necrotic cells associated with them than those that were grown at 19 °C. The incidence of colony-associated necrosis in these leaves could be further reduced by increasing the temperature to 26 °C and 27 °C. Similarly, the number of necrotic host cells per colony decreased with an increase in temperature. Colonies in genotypically resistant leaves were usually smaller than those in genotypically susceptible leaves, but the differences in colony sizes between these two lines decreased at the higher temperatures.When infected plants containing the Sr6 gene were kept for varying times at 25 °C and then were transferred to 19 °C, there was significantly less fungal growth and more necrosis than in plants kept continuously at 25 °C. This necrosis occurred largely in those cells that were invaded after the transfer to 19 °C, when the Sr6 gene was activated.

Molecular characterization and chromosome-specific TRAP-marker development for Langdon durum D-genome disomic substitution lines

Genome ◽  
2006 ◽  
Vol 49 (12) ◽  
pp. 1545-1554 ◽  
Author(s):  
J. Li ◽  
D.L. Klindworth ◽  
F. Shireen ◽  
X. Cai ◽  
J. Hu ◽  
...  
Keyword(s):  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Substitution Lines ◽  
Genome Chromosome ◽  
D Genome ◽  
Single Chromosome ◽  
B Genome ◽  
The Individual ◽  
Trap Marker

The aneuploid stocks of durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husnot) and common wheat ( T. aestivum L.) have been developed mainly in ‘Langdon’ (LDN) and ‘Chinese Spring’ (CS) cultivars, respectively. The LDN-CS D-genome chromosome disomic substitution (LDN-DS) lines, where a pair of CS D-genome chromosomes substitute for a corresponding homoeologous A- or B-genome chromosome pair of LDN, have been widely used to determine the chromosomal locations of genes in tetraploid wheat. The LDN-DS lines were originally developed by crossing CS nulli-tetrasomics with LDN, followed by 6 backcrosses with LDN. They have subsequently been improved with 5 additional backcrosses with LDN. The objectives of this study were to characterize a set of the 14 most recent LDN-DS lines and to develop chromosome-specific markers, using the newly developed TRAP (target region amplification polymorphism)-marker technique. A total of 307 polymorphic DNA fragments were amplified from LDN and CS, and 302 of them were assigned to individual chromosomes. Most of the markers (95.5%) were present on a single chromosome as chromosome-specific markers, but 4.5% of the markers mapped to 2 or more chromosomes. The number of markers per chromosome varied, from a low of 10 (chromosomes 1A and 6D) to a high of 24 (chromosome 3A). There was an average of 16.6, 16.6, and 15.9 markers per chromosome assigned to the A-, B-, and D-genome chromosomes, respectively, suggesting that TRAP markers were detected at a nearly equal frequency on the 3 genomes. A comparison of the source of the expressed sequence tags (ESTs), used to derive the fixed primers, with the chromosomal location of markers revealed that 15.5% of the TRAP markers were located on the same chromosomes as the ESTs used to generate the fixed primers. A fixed primer designed from an EST mapped on a chromosome or a homoeologous group amplified at least 1 fragment specific to that chromosome or group, suggesting that the fixed primers might generate markers from target regions. TRAP-marker analysis verified the retention of at least 13 pairs of A- or B-genome chromosomes from LDN and 1 pair of D-genome chromosomes from CS in each of the LDN-DS lines. The chromosome-specific markers developed in this study provide an identity for each of the chromosomes, and they will facilitate molecular and genetic characterization of the individual chromosomes, including genetic mapping and gene identification.

The biology and ecology of hexaploid wheat (Triticum aestivum L.) and its implications for trait confinement

2008 ◽  
Vol 88 (5) ◽  
pp. 997-1013 ◽  
Author(s):  
C. J. Willenborg ◽  
R. C. Van Acker
Keyword(s):  
Triticum Aestivum ◽  
Gene Flow ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Cropping Systems ◽  
Pollen Viability ◽  
Triticum Aestivum L ◽  
Genetically Engineered ◽  
Wide Range ◽  
Trait Confinement

This review summarizes the biological and ecological factors of hexaploid wheat (Triticum aestivum L.) that contribute to trait movement including the ability to volunteer, germination and establishment characteristics, breeding system, pollen movement, and hybridization potential. Although wheat has a short-lived seedbank with a wide range of temperature and moisture requirements for germination and no evidence of secondary dormancy, volunteer wheat populations are increasing in relative abundance and some level of seed persistence in the soil has been observed. Hexaploid wheat is predominantly self-pollinating with cleistogamous flowers and pollen viability under optimal conditions of only 0.5 h, yet observations indicate that pollen-mediated gene flow can and will occur at distances up to 3 km and is highly dependent on prevailing wind patterns. Hybridization with wild relatives such as A. cylindrica Host., Secale cereale L., and Triticum turgidum L. is a serious concern in regions where these species grow in field margins and unmanaged lands, regardless of which genome the transgene is located on. More research is needed to determine the long-term population dynamics of volunteer wheat populations before conclusions can be drawn with regard to their role in trait movement. Seed movement has the potential to create adventitious presence (AP) on a larger scale than pollen, and studies tracing the movement of wheat seed in the grain handling system are needed. Finally, the development of mechanistic models that predict landscape-level trait movement are required to identify transgene escape routes and critical points for gene containment in various cropping systems. Key words: Triticum, coexistence, gene flow, genetically-engineered, herbicide-resistant, trait confinement

INHERITANCE OF THE TYPE OF SOLID STEM IN GOLDEN BALL (TRITICUM DURUM): II. CYTOGENETICS OF THE RELATION BETWEEN SOLID STEM AND OTHER MORPHOLOGICAL CHARACTERS IN HEXAPLOID F5 LINES OF A HYBRID WITH RESCUE (T. AESTIVUM)

1959 ◽  
Vol 37 (6) ◽  
pp. 1207-1216 ◽  
Author(s):  
Ruby I. Larson
Keyword(s):  
Triticum Aestivum ◽  
Triticum Durum ◽  
Triticum Aestivum L ◽  
Morphological Characters ◽  
Genome Chromosome ◽  
D Genome ◽  
Stem Solidness ◽  
Pentaploid Hybrid ◽  
Golden Ball ◽  
Solid Stem

Cytogenetic analysis of selected F5 lines of the pentaploid hybrid, Rescue (Triticum aestivum L. emend. Thell.) × Golden Ball (T. durum Desf.) showed that chromosome XVI is the member of the D genome of Rescue that prevents transfer of the more solid top culm internode of Golden Ball to hexaploid segregates. It also produces a lax spike. Chromosome XX, which is the D-genome chromosome mainly responsible for the hollowness of hollow-stemmed hexaploids, probably has little effect in Rescue. Long awns were associated with low chromosome number but not with stem solidness or dense spike; therefore, the chromosome that suppresses awn development is probably not XVI.Three 42-chromosome segregates from the cross were more solid in the top internode than Rescue, presumably because of segregation of genes in the A and B genomes. It is unlikely, however, that a fully hexaploid segregate with a top internode as solid as that of Golden Ball can be selected from this hybrid.

scholarly journals Influence of homoeologous chromosomes on gene-dosage effects in allohexaploid wheat (Triticum aestivum L.).

1978 ◽  
Vol 75 (3) ◽  
pp. 1446-1450 ◽  
Author(s):  
C. Aragoncillo ◽  
M. A. Rodriguez-Loperena ◽  
G. Salcedo ◽  
P. Carbonero ◽  
F. Garcia-Olmedo
Keyword(s):  
Triticum Aestivum ◽  
Gene Dosage ◽  
Triticum Aestivum L ◽  
Gene Dosage Effects ◽  
Dosage Effects ◽  
Allohexaploid Wheat ◽  
Homoeologous Chromosomes
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