CYTOGENETICS OF SOLID STEM IN COMMON WHEAT: I. MONOSOMIC F2 ANALYSIS OF THE VARIETY S-615

1959 ◽  
Vol 37 (1) ◽  
pp. 135-156 ◽  
Author(s):  
Ruby I. Larson
Keyword(s):  
Cross Sections ◽  
Chinese Spring ◽  
Continuous Distribution ◽  
Homoeologous Group ◽  
D Genome ◽  
Index Numbers ◽  
Stem Solidness ◽  
Thin Walled ◽  
Solid Stem ◽  
Group 2

The F2 lines of monosomics of Chinese Spring by S-615 were compared with normal F2 lines for stem solidness. The solid stem index of each plant was determined by totalling index numbers (ranging from 1 for thin-walled, hollow, to 5 for completely solid) assigned to cross sections of the culm at seven designated points. As both the normal and monosomic lines showed a continuous distribution of this index, the factorial analysis was not too reliable. The normal F2 gave an estimated difference between the parents of at least four genes; the monosomic XIII F2, which was more solid than the normal, gave a difference of three genes.Quantitative differences between monosomic F2 lines and the normal indicated that chromosomes II, XIII, and XX, comprising homoeologous group 2, tend to make the culm hollow. Chromosomes XIX and XXI also inhibit pith development. Of these five chromosomes, XIII has a gene for hollow culm in Chinese Spring only; XIX, XX, and XXI, which are in the D genome, are effective in both S-615 and Chinese Spring, and II is inconclusive. Chromosome VIII in Chinese Spring promotes pith production. The chromosomes of S-615 bearing genes for solid stem were not identified by this method, as a monosomic F2 analysis does not reveal recessives present only in the variety being tested.

CYTOGENETICS OF SOLID STEM IN COMMON WHEAT: II. STEM SOLIDNESS OF MONOSOMIC LINES OF THE VARIETY S-615

1959 ◽  
Vol 37 (3) ◽  
pp. 365-378 ◽  
Author(s):  
Ruby I. Larson ◽  
M. D. MacDonald
Keyword(s):  
Common Wheat ◽  
Chinese Spring ◽  
Homoeologous Group ◽  
D Genome ◽  
Stem Solidness ◽  
Group 3 ◽  
Solid Stem ◽  
Group 5

Lines of a variety of common wheat, S-615, monosomic for chromosomes III and XVI of homoeologous group 3 had culms less solid in the top internode than normal S-615. Monosomics of homoeologous group 5, namely, V, IX, and XVIII, were less solid in the bottom four internodes than S-615. These five chromosomes carry genes for solid stem in this variety. Monosomics XIX, XX, and XXI, the D-genome chromosomes of homoeologous groups 6, 2, and 7 respectively, were more solid than the normal check in both top and lower internodes, indicating that the missing chromosomes carry genes for hollow stem. Chromosome XIII, a homoeologue of XX, which in Chinese Spring has a gene for hollow stem, does not affect the amount of pith in the culm of S-615.The concept of the culm phenotype in a given environment resulting from an interaction of genes promoting pith development and those opposing it makes it possible to reconcile results of genetic experiments on solid stem in wheat that previously appeared contradictory.

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.

CYTOGENETICS OF SOLID STEM IN COMMON WHEAT: III. CULM MEASUREMENTS AND THEIR RELATION TO STEM SOLIDNESS IN MONOSOMIC LINES OF THE VARIETY S-615

1959 ◽  
Vol 37 (3) ◽  
pp. 379-391 ◽  
Author(s):  
Ruby I. Larson ◽  
M. D. MacDonald
Keyword(s):  
Common Wheat ◽  
Chinese Spring ◽  
Monosomic Analysis ◽  
Secondary Effects ◽  
Stem Solidness ◽  
Solid Stem ◽  
Homoeologous Chromosomes

Most monosomics of the solid-stemmed variety of common wheat, S-61S, were shorter than normal. Many had thinner culms, but monosomics XIII and XVI had thicker culms. Although the effect of loss of homoeologous chromosomes on culm dimensions was generally similar in S-615 monosomics and Chinese Spring nullisomics, the most extreme member of each group was not always the same in the two varieties. The differences between solid stem in monosomics and normal lines of S-615 were due to loss of the chromosome affecting pith production and not to secondary effects caused by changes in culm dimensions. Nevertheless, within lines of genetically similar plants there was a small but consistent association between short culm and solidness, between thin culm at the tops of internodes I, III, and IV and hollowness, and between thin culm in the center and lower parts of internode I and solidness. This has a bearing on interpretation of data in monosomic analysis of solid stem.

Molecular mapping of wheat. Homoeologous group 2

Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 516-524 ◽  
Author(s):  
James C. Nelson ◽  
Allen E. Van Deynze ◽  
Mark E. Sorrells ◽  
Enrique Autrique ◽  
Yun Hai Lu ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Molecular Mapping ◽  
Triticum Aestivum L ◽  
Homoeologous Group ◽  
Hordeum Vulgare L ◽  
Crop Species ◽  
D Genome ◽  
Wheat Group ◽  
Group 2 ◽  
Stem Rust Resistance Genes

A molecular-marker map of bread wheat having many markers in common with other grasses in the Gramineae family is a prerequisite for molecular level genetic studies and breeding in this crop species. We have constructed restriction fragment length polymorphism maps of the A-, B-, and D-genome chromosomes of homoeologous group 2 of hexaploid wheat (Triticum aestivum L. em. Thell) using 114 F7 lines from a synthetic × bread wheat cross and clones from 11 libraries. Chromosomes 2A, 2B, and 2D comprise 57, 60, and 56 markers and each spans about 200 cM. Comparisons between chromosomes are facilitated by 26 sets of homoeoloci. Genes mapped include a heterologous abscisic acid responsive locus cloned as pBS128, the epidermal waxiness inhibitor W21, and two presumed leaf rust and stem rust resistance genes. Anomalies suggesting ancestral rearrangements in chromosome 2B are pointed out and features of wheat group 2 chromosomes that are common to barley (Hordeum vulgare L.), rice (Oryza spp.), and T. tauschii are discussed.Key words: RFLP, wheat, waxy, rust.

scholarly journals The incorporation of alien disease resistance in wheat by genetic interference with the regulation of meiotic chromosome synapsis

1968 ◽  
Vol 12 (2) ◽  
pp. 199-219 ◽  
Author(s):  
Ralph Riley ◽  
Victor Chapman ◽  
Roy Johnson
Keyword(s):  
Chinese Spring ◽  
Rust Resistance ◽  
Yellow Rust ◽  
Proximal Segment ◽  
Recurrent Parent ◽  
Homoeologous Recombination ◽  
Homoeologous Group ◽  
Chromosome 5B ◽  
Group 2 ◽  
Meiotic Synapsis

1. Triticum aestivum ssp. vulgare variety Chinese Spring (2n = 6x = 42) is susceptible to yellow rust caused by Puccinia striiformis while the wild annual grass Aegilops comosa (2n = 14) is resistant to all the physiologic races for which it has been tested.2. By a backcrossing programme initiated from Chinese Spring × Ae. comosa hybrids, using Chinese Spring as the recurrent parent, a line was isolated with a single chromosome of Ae. comosa, determining rust resistance, added to the full complement of Chinese Spring.3. The alien chromosome substituted with good genetic compensation only for the chromosomes of homoeologous group 2 of Chinese Spring. This demonstrated that the chromosome determining rust resistance is in homoeologous group 2. It was designated 2M since Ae. comosa has the M genome.4. In order to induce recombination between 2M and its wheat homoeologues, hybrids were made using Ae. speltoides which has the capacity to suppress the activity of chromosome 5B that normally prevents homoeologous synapsis. A backcrossing programme, using Chinese Spring as the recurrent parent, was reinitiated from the 29-chromosome hybrids carrying chromosome 2M and the haploid complements of Chinese Spring and Ae. speltoides.5. Selection was practised for rust resistance and ultimately a resistant plant with 42 chromosomes, that formed 21 bivalents at meiosis, was isolated. This plant was heterozygous for a dominant rust resistance allele (Yr8) derived from Ae. comosa. Homozygotes were isolated in its progeny and in this way the rust resistant breeder's variety, Compair, was established.6. Compair differs from Chinese Spring in its yellow rust resistance which was shown to be determined by a chromosome corresponding to 2D of Chinese Spring. This chromosome of Compair has the short arm, the centromere and a proximal segment of the long arm of chromosome 2M and a distal segment of the right arm of chromosome 2D. The modified chromosome, which is designated 2M/D, arose by homoeologous recombination in the Ae. speltoides hybrid or in the immediately succeeding backcross generations. Chromosome 2M/D carries the Yr8 gene in the proximal segment of the long arm derived from chromosome 2M.7. In hybrids between Compair and standard wheat varieties, chromosome 2M/D pairs regularly with chromosome 2D so that regular segregation of Yr8 can be expected and Compair treated like any other parental variety in wheat hybridization programmes.8. This work illustrates the way that homoeologous recombination can be induced and exploited both in cytogenetic analysis in wheat and in practical breeding work. The nature of the meiotic synapsis of chromosome 2M/D with its partial homologues raises questions concerning the means by which chromosome 5B influences the specificity of meiotic synapsis.

scholarly journals Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3468
Author(s):  
Zbigniew Kolakowski ◽  
Andrzej Teter
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Equilibrium Path ◽  
Load Carrying Capacity ◽  
Nonlinear Buckling ◽  
Elastic Range ◽  
Load Carrying ◽  
Thin Walled ◽  
Ultimate Load Carrying Capacity

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.

A torsion bending element for thin-walled beams with open and closed cross sections

1995 ◽  
Vol 55 (6) ◽  
pp. 1045-1054 ◽  
Author(s):  
H. Shakourzadeh ◽  
Y.Q. Guo ◽  
J.-L. Batoz
Keyword(s):  
Cross Sections ◽  
Thin Walled

Numerical Investigation of Cross-Section on Aluminum A6063 Thin-Walled Structures under Low-Velocity Impact Loading

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Cross Sections ◽  
Peak Load ◽  
Circular Cross Section ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Crush Strength

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.

scholarly journals INFLUENCE OF PERIODIC SHADING ON THE LENGTH AND SOLIDNESS OF THE INTERNODES OF RESCUE WHEAT

1960 ◽  
Vol 40 (1) ◽  
pp. 183-187 ◽  
Author(s):  
N. D. Holmes ◽  
R. I. Larson ◽  
L. K. Peterson ◽  
M. D. MacDonald
Keyword(s):  
Light Intensity ◽  
Cross Sections ◽  
Strongly Correlated ◽  
Boot Stage ◽  
Stem Solidness ◽  
Heading Stage

Shading at the initiation of elongation shortened the internodes of Rescue wheat whereas shading later in the elongation period caused the internodes to elongate as much as or more than if they had not been shaded.The solidness of the bottom Internode, 1, was reduced mainly by shading from the 2-leaf to the boot stage, while that of Internodes 2 and 3 was reduced mainly by shading from the 4-leaf to the boot stage. The solidness of Internode 4 was reduced mainly by shading from the boot to the heading stage. The solidness in the lower 3 internodes was affected by reduction in light intensity even after the boot stage. Severe lodging occurred only in stems shaded from the boot to the heading stage.Two methods were used for rating stem solidness, namely, measurement in the split stem of proportion of the internode filled with pith, and classification of solidness of cross-sections at designated points in each internode. They were strongly correlated and appeared to give equally accurate estimates of solidness, although their degrees of sensitivity varied with the amount of stem solidness present.

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