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

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.

1959 ◽  
Vol 37 (1) ◽  
pp. 135-156 ◽  
Author(s):  
Ruby I. Larson

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.


1959 ◽  
Vol 37 (3) ◽  
pp. 379-391 ◽  
Author(s):  
Ruby I. Larson ◽  
M. D. MacDonald

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.


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.


1986 ◽  
Vol 28 (4) ◽  
pp. 497-501 ◽  
Author(s):  
Eitan Millet

Various aneuploids of common wheat (Triticum aestivum L.) cv. Chinese Spring were used to study the dosage effect of group-5 chromosomes on spike morphology, size of floral organs, and grain weight. Reduced dosage resulted in smaller floral organs, smaller floret cavities, and lighter grains than in the euploid, while increased dosage had the opposite effects. Chromosome 5A was the most effective in inducing these changes, whereas in most cases 5B was the least effective. Based on the various lines studied, a high linear correlation was found between the weight of the basal grains in the central spikelets and the volume estimates of the florets in which they were developed. The different lines exhibited a considerable similarity between the size distribution of floral organs and the grain weight distribution in the main spike. Pleiotropic effects of genes located on group-5 chromosomes on size of floral organs and grain weight are suggested.Key words: Wheat, aneuploids, group-5 chromosomes.


1952 ◽  
Vol 30 (4) ◽  
pp. 371-378 ◽  
Author(s):  
J. W. Morrison ◽  
John Unrau

The frequency with which 20 different monosomes of the common wheat variety, Chinese Spring, formed micronuclei in pollen quartets was determined. It was found that unless the study was made at an early developmental stage characterized by a distinct cell wall surrounding the quartets, the counts were unreliable, because some micronuclei were lost. The frequency of micronucleus formation was similar for anthers of a floret, florets of a spike, and plants of a monosome. Among the monosomes studied, there were three groups of three and four of two in which the total frequency of quartets with micronuclei, and the distribution of numbers of micronuclei per quartet, were strikingly similar. In the case of the groups of three, two monosomes were from the A and B genomes while one was from the D genome. This is interpreted as evidence of homoeology of chromosomes of a group and also that such chromosomes have undergone less change than those that do not form such series.


1959 ◽  
Vol 37 (6) ◽  
pp. 1207-1216 ◽  
Author(s):  
Ruby I. Larson

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.


2008 ◽  
Vol 88 (6) ◽  
pp. 1065-1071 ◽  
Author(s):  
Qijiao Chen ◽  
Lianquan Zhang ◽  
Zhongwei Yuan ◽  
Zehong Yan ◽  
Youliang Zheng ◽  
...  

Due to the high polymorphisms between synthetic hexaploid wheat (SHW) and common wheat, SHW has been widely used in genetic studies. The transferability of simple sequence repeats (SSR) among common wheat and its donor species, Triticum turgidum and Aegilops tauschii, and their SHW suggested the possibility that some SSRs, specific for a single locus in common wheat, might appear in two or more loci in SHWs. This is an important genetic issue when using synthetic hexaploid wheat population and SSR for mapping. However, it is largely ignored and never empirically well verified. The present study addressed this issue by using the well-studied SSR marker Xgwm261 as an example. The Xgwm261 produced a 192 bp fragment specific to chromosome 2D in common wheat Chinese Spring, but generated a 176 bp fragment in the D genome of Ae. tauschii AS60. Chromosomal location and DNA sequence data revealed that the176 bp fragment also donated by 2B chromosome of durum wheat Langdon. These results indicated that although a single 176 bp fragment was appeared in synthetic hexaploid wheat Syn-SAU-5 between Langdon and AS60, the fragment contained two different loci, one from chromosome 2D of AS60 and the other from 2B of Langdon which were confirmed by the segregating analysis of SSR Xgwm261 in 185 plants from a F2 population between Syn-SAU-5 and Chinese Spring. If Xgwm261 in Syn-SAU-5 was considered as a single locus in genetic analysis, distorted segregation or incorrect conclusions would be yielded. A proposed strategy to avoid this problem is to include SHW’s parental T. turgidum and Ae. tauschii in SSR analysis as control for polymorphism detection. Key words: Synthetic hexaploid wheat, microsatellite, segregation distortion, Xgwm261, transferability


Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 525-533 ◽  
Author(s):  
James C. Nelson ◽  
Allen E. Van Deynze ◽  
Mark E. Sorrells ◽  
Enrique Autrique ◽  
Yun Hai Lu ◽  
...  

A prerequisite for molecular level genetic studies and breeding in wheat is a molecular marker map detailing its similarities with those of other grass species in the Gramineae family. We have constructed restriction fragment length polymorphism maps of the A-, B-, and D-genome chromosomes of homoeologous group 3 of hexaploid wheat (Triticum aestivum L. em. Thell) using 114 F7–8 lines from a synthetic × bread wheat cross. The map consists of 58 markers spanning 230 cM on chromosome 3A, 62 markers spanning 260 cM on 3B, and 40 markers spanning 171 cM on 3D. Thirteen libraries of genomic or cDNA clones from wheat, barley, and T. tauschii, the wheat D genome donor, are represented, facilitating the alignment and comparison of these maps with maps of other grass species. Twenty-four clones reveal homoeoloci on two of the three genomes and the associated linkages are largely comparable across genomes. A consensus sequence of orthologous loci in grass species genomes is assembled from this map and from existing maps of the chromosome-3 homoeologs in barley (Hordeum spp.), T. tauschii, and rice (Oryza spp.). It illustrates the close homoeology among the four species and the partial homoeology of wheat chromosome 3 with oat (Avena spp.) chromosome C. Two orthologous red grain color genes, R3 and R1, are mapped on chromosome arms 3BL and 3DL.Key words: RFLP, wheat, barley, Triticum tauschii, grain color.


1976 ◽  
Vol 18 (2) ◽  
pp. 211-216 ◽  
Author(s):  
G. M. Halloran

The altered vernalization response of normal Chinese Spring caused by the three individually-substituted chromosomes of homoeologous group 5 of Hope in Chinese Spring was found to be controlled by a single gene on each chromosome. The alleles on chromosomes 5A and 5B of Hope are dominant to those on their respective homologues in Chinese Spring for lowered vernalization response, while that on Hope 5D is dominant to that on Chinese Spring 5D for increased vernalization response. The possibility has been discussed of the vernalization response locus on Hope 5D bearing a null allele or an allele with very little involvement in the vernalization process, in which case the strong vernalization response exhibited by Chinese Spring/Hope 5D could merely be a function of genes promoting vernalization response in the rest of the Chinese Spring genotype.


1999 ◽  
Vol 89 (4) ◽  
pp. 293-297 ◽  
Author(s):  
J. A. Anderson ◽  
R. J. Effertz ◽  
J. D. Faris ◽  
L. J. Francl ◽  
S. W. Meinhardt ◽  
...  

The fungus Pyrenophora tritici-repentis produces a toxin (Ptr ToxA) that causes rapid cell necrosis in sensitive wheat genotypes. A single recessive gene (tsn1) on chromosome 5BL in common wheat confers insensitivity to this toxin. Our objectives were to analyze the allelic relationships of genotypes that have shown insensitivity to a P. tritici-repentis necrosis-inducing toxin, map the gene for insensitivity to the necrosis-inducing factor produced by P. tritici-repentis in a durum wheat population, and determine the reaction to P. tritici-repentis of aneuploid genotypes that do not contain the gene. Greenhouse-grown plants of seven populations from crosses of insensitive genotypes; an F2 population of durum wheat; and ‘Chinese Spring’ aneuploid, substitution, and deletion lines were infiltrated with Ptr ToxA. All crosses involving insensitive genotypes failed to produce sensitive progeny, indicating that the same gene is present in these genotypes. The gene for insensitivity in the durum population was mapped to the same region on 5BL as in common wheat using restriction fragment length polymorphism markers. ‘Chinese Spring’, its homoeologous group 5 nullisomic-tetrasomic stocks, and 5BL deletion lines were insensitive to the toxin. Substitution of a 5B chromosome from sensitive genotypes into ‘Chinese Spring’ resulted in sensitivity. Therefore, insensitivity is not conferred by a gene product per se, but rather conferred by absence of a gene for sensitivity.


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