Analysis of induced homoeologous pairing in hybrids between 6x triticale ph1 mutant and Triticum aestivum L.

1986 ◽  
Vol 28 (5) ◽  
pp. 696-700 ◽  
Author(s):  
Nicolás Jouve ◽  
Benito Giorgi
Keyword(s):  
Triticum Aestivum ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Hexaploid Triticale ◽  
D Genome ◽  
Level Of Involvement ◽  
Mother Cells ◽  
Homoeologous Chromosomes ◽  
Different Doses ◽  
Induced Homoeologous Pairing

The meiotic behaviour of three hexaploid triticale × Triticum aestivum L. hybrids having different doses of ph1 mutant alleles was investigated using C-band staining of pollen mother cells at first metaphase. D-genome chromosomes that were clearly distinguished by their small size and unbanded response to Giemsa staining were increasingly promoted to pair with the homoeologous chromosomes of the A and B genomes in the absence of Ph1 genes. However, the wheat–rye associations were not enhanced when one or two ph1 alleles were present. The distribution of meiotic configurations was significantly different for each chromosome in the ph1/ph1 hybrid. Thus, 1B did not form multivalents in this hybrid, and the remaining identified chromosomes differed significantly in the level of involvement in tri-, quadri-, or quinque-valents. The hybrids should be of value for hexaploid and wheat breeding programs.Key words: Triticale, Triticum aestivum, C-banding, ph1 mutants.

NONSTRUCTURAL CHROMOSOME DIFFERENTIATION AMONG WHEAT CULTIVARS, WITH SPECIAL REFERENCE TO DIFFERENTIATION OF CHROMOSOMES IN RELATED SPECIES

Genetics ◽  
1981 ◽  
Vol 97 (2) ◽  
pp. 391-414
Author(s):  
Jan Dvořák ◽  
Patrick E McGuire
Keyword(s):  
Chinese Spring ◽  
Structural Changes ◽  
Wheat Cultivar ◽  
Chromosome Complement ◽  
Triticum Aestivum L ◽  
Substitution Lines ◽  
Structural Differentiation ◽  
Chromosome Differentiation ◽  
Mother Cells ◽  
Homoeologous Chromosomes

ABSTRACT Wheat cultivar Chinese Spring (Triticum aestivum L. em. Thell.) was crossed with cultivars Hope, Cheyenne and Timstein. In all three hybrids, the frequencies of pollen mother cells (PMCs) with univalents at metaphase I (MI) were higher than those in the parental cultivars. No multivalents were observed in the hybrids, indicating that the cultivars do not differ by translocations. Thirty-one Chinese Spring telosomic lines were then crossed with substitution lines in which single chromosomes of the three cultivars were substituted for their Chinese Spring homologues. The telosomic lines were also crossed with Chinese Spring. Data were collected on the frequencies (% of PMCs) of pairing of the telesomes with their homologues at MI and the regularity of pairing of the remaining 20 pairs of Chinese Spring chromosomes in the monotelodisomics obtained from these crosses. The reduced MI pairing in the intercultivar hybrids was caused primarily by chromosome differentiation, rather than by specific genes. Because the differentiation involved a large part of the chromosome complement in each hybrid, it was concluded that it could not be caused by structural changes such as inversions or translocations. In each case, the differentiation appeared to be unevenly distributed among the three wheat genomes. It is proposed that the same kind of differentiation, although of greater magnitude, differentiates homoeologous chromosomes and is responsible, together with structural differentiation, for poor chromosome pairing in interspecific hybrids.

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.

COLD HARDINESS IN HEXAPLOID TRITICALE

1985 ◽  
Vol 65 (3) ◽  
pp. 487-490 ◽  
Author(s):  
A. E. LIMIN ◽  
J. DVORAK ◽  
D. B. FOWLER
Keyword(s):  
Cold Hardiness ◽  
Tetraploid Wheat ◽  
Triticum Aestivum L ◽  
Hexaploid Triticale ◽  
D Genome ◽  
Potential Source ◽  
Secale Cereale L ◽  
Cold Hardy ◽  
Triticosecale Wittmack ◽  
X Triticosecale Wittmack

The excellent cold hardiness of rye (Secale cereale L.) makes it a potential source of genetic variability for the improvement of this character in related species. However, when rye is combined with common wheat (Triticum aestivum L.) to produce octaploid triticale (X Triticosecale Wittmack, ABDR genomes), the superior rye cold hardiness is not expressed. To determine if the D genome of hexaploid wheat might be responsible for this lack of expression, hexaploid triticales (ABR genomes) were produced and evaluated for cold hardiness. All hexaploid triticales had cold hardiness levels similar to their tetraploid wheat parents. Small gains in cold hardiness of less than 2 °C were found when very non-hardy wheats were used as parents. This similarity in expression of cold hardiness in both octaploid and hexaploid triticales indicates that the D genome of wheat is not solely, if at all, responsible for the suppression of rye cold hardiness genes. There appears to be either a suppressor(s) of the rye cold hardiness genes on the AB genomes of wheat, or the expression of diploid rye genes is reduced to a uniform level by polyploidy in triticale. The suppression, or lack of expression, of rye cold hardiness genes in a wheat background make it imperative that cold-hardy wheats be selected as parents for the production of hardy triticales.Key words: Triticale, Secale, winter wheat, cold hardiness, gene expression

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

GENETIC REGULATION OF HETEROGENETIC CHROMOSOME PAIRING IN POLYPLOID SPECIES OF THE GENUS TRITICUM sensu lato

1982 ◽  
Vol 24 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Patrick E. McGuire ◽  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Genetic Regulation ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
D Genome ◽  
Chromosome 5B ◽  
A Genome

Polyploid species of Triticum sensu lato were crossed with Triticum aestivum L. em. Thell. cv. Chinese Spring monotelodisomics or ditelosomics that were monosomic for chromosome 5B. Progeny from these crosses were either euploid, nullisomic for 5B, monotelosomic for a given Chinese Spring chromosome, or nullisomic for 5B and monotelosomic simultaneously. The Chinese Spring telosome in the hybrids permitted the evaluation of autosyndesis of chromosomes of the tested species. In addition, several Chinese Spring eu- and aneuhaploids were produced. Genotypes of T. cylindricum Ces., T. juvenale Thell., T. triunciale (L.) Raspail, T. ovatum (L.) Raspail, T. columnare (Zhuk.) Morris et Sears, T. triaristatum (Willd.) Godr. et Gren., and T. rectum (Zhuk.) comb. nov. were all shown to have suppressive effects on heterogenetic pairing in hybrids lacking 5B or 3AS, whereas T. kotschyi (Boiss.) Bowden had no effect. It was concluded that diploid-like meiosis in these species is due to genetic regulation. A number of these genotypes promoted heterogenetic pairing in the presence of 5B. A model is presented to explain this dichotomous behavior of the tested genotypes. Monotelosomic-3AL haploids had a greater amount of pairing than did euhaploid Chinese Spring, which substantiated the presence of a pairing suppressor(s) on the 3AS arm. Evidence is presented that shows that T. juvenale does not have a genome homologous with the D genome of T. aestivum.

CYTOLOGY AND FERTILITY OF PENTAPLOID WHEAT HYBRIDS WITH INDUCED PAIRING BETWEEN HOMOEOLOGOUS CHROMOSOMES

1982 ◽  
Vol 24 (4) ◽  
pp. 397-408 ◽  
Author(s):  
U. Kushnir ◽  
G. M. Halloran
Keyword(s):  
Chromosome Pairing ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Triticum Aestivum L ◽  
The Other ◽  
Homoeologous Chromosome ◽  
D Genome ◽  
Homoeologous Chromosome Pairing ◽  
Wheat Hybrids ◽  
Homoeologous Chromosomes

Two mutants, each promoting homoeologous chromosome pairing in hexaploid wheat (Triticum × aestivum L. emend gr. aestivum), in the cultivar Chinese Spring, ph1b at the Ph locus on chromosome 5BL and the other, ph2, on chromosome 3DS, were compared for their influence on chromosome pairing and fertility in pentaploid hybrids with Triticum turgidum L. emend var. dicoccoides (Korn. in litt. in Schweinf.). The mutants induced increased multivalent frequency over the normal pentaploid. Lower univalent frequencies in the ph2-pentaploid, compared with the normal pentaploid, indicated that D-genome chromosomes of the former were substantially involved in homoeologous pairing. Certain differences in other meiotic processes and fertility among the pentaploids may reflect differences in the activity of the pairing genes. There appeared to be a higher level of univalent elimination in pollen and egg cells in the ph2-, compared with the ph1b-pentaploid. Tetrad formation was close to normal in the ph2- pentaploid but exhibited high levels of abnormality (monads, dyads, triads and apolar tetrads) in the ph1b-pentaploid. Fertility levels in crosses of the pentaploids with hexaploid wheat, while low, were much lower for the ph1b-, compared with the ph2-pentaploid.

Competitive ability of wheat in conventional and organic management systems: A review of the literature

2006 ◽  
Vol 86 (2) ◽  
pp. 333-343 ◽  
Author(s):  
H. E. Mason ◽  
D. Spaner
Keyword(s):  
Triticum Aestivum ◽  
Leaf Area ◽  
Organic Agriculture ◽  
Competitive Ability ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Management Systems ◽  
Wheat Varieties ◽  
Early Season ◽  
Low Input

Wheat (Triticum aestivum L.) is the world’s most widely grown crop, cultivated in over 115 nations. Organic agriculture, a production system based on reducing external inputs in order to promote ecosystem health, can be defined as a system that prohibits the use of synthetic fertilizers, chemical pesticides and genetically modified organisms. Organic agriculture is increasing in popularity, with a 60% increase in the global acreage of organically managed land from the year 2000 to 2004. Constraints that may be associated with organic grain production include reduced yields due to soil nutrient deficiencies and competition from weeds. Global wheat breeding efforts over the past 50 yr have concentrated on improving yield and quality parameters; in Canada, disease resistance and grain quality have been major foci. Wheat varieties selected before the advent of chemical fertilizers and pesticides may perform differently in organic, low-input management systems than in conventional, high-input systems. Height, early-season growth, tillering capacity, and leaf area are plant traits that may confer competitive ability in wheat grown in organic systems. Wheat root characteristics may also affect competitive ability, especially in low-input systems, and more research in this area is needed. The identification of a competitive crop ideotype may assist wheat breeders inthe development of competitive wheat varieties. Wheat varieties with superior performance in low-input systems, and/or increased competitive ability against weeds, could assist organic producers in overcoming some of the constraints associated with organic wheat production. Key words: Triticum aestivum L., wheat breeding, low-input agriculture, plant height, early-season growth, tillering capacity, leaf area index

scholarly journals Population structure of Nepali spring wheat (Triticum aestivum L.) germplasm

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Kamal Khadka ◽  
Davoud Torkamaneh ◽  
Mina Kaviani ◽  
Francois Belzile ◽  
Manish N. Raizada ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Triticum Aestivum ◽  
Population Structure ◽  
Food Security ◽  
Spring Wheat ◽  
Principal Component ◽  
Genotyping By Sequencing ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Exotic Germplasm

Abstract Background Appropriate information about genetic diversity and population structure of germplasm improves the efficiency of plant breeding. The low productivity of Nepali bread wheat (Triticum aestivum L.) is a major concern particularly since Nepal is ranked the 4th most vulnerable nation globally to climate change. The genetic diversity and population structure of Nepali spring wheat have not been reported. This study aims to improve the exploitation of more diverse and under-utilized genetic resources to contribute to current and future breeding efforts for global food security. Results We used genotyping-by-sequencing (GBS) to characterize a panel of 318 spring wheat accessions from Nepal including 166 landraces, 115 CIMMYT advanced lines, and 34 Nepali released varieties. We identified 95 K high-quality SNPs. The greatest genetic diversity was observed among the landraces, followed by CIMMYT lines, and released varieties. Though we expected only 3 groupings corresponding to these 3 seed origins, the population structure revealed two large, distinct subpopulations along with two smaller and scattered subpopulations in between, with significant admixture. This result was confirmed by principal component analysis (PCA) and UPGMA distance-based clustering. The pattern of LD decay differed between subpopulations, ranging from 60 to 150 Kb. We discuss the possibility that germplasm explorations during the 1970s–1990s may have mistakenly collected exotic germplasm instead of local landraces and/or collected materials that had already cross-hybridized since exotic germplasm was introduced starting in the 1950s. Conclusion We suggest that only a subset of wheat “landraces” in Nepal are authentic which this study has identified. Targeting these authentic landraces may accelerate local breeding programs to improve the food security of this climate-vulnerable nation. Overall, this study provides a novel understanding of the genetic diversity of wheat in Nepal and this may contribute to global wheat breeding initiatives.

scholarly journals Radiosensitivity of Some Local Cultivars of Wheat (Triticum Aestivum L.) to Gamma Irradiation

2012 ◽  
Vol 41 (1) ◽  
pp. 1-5 ◽  
Author(s):  
MMA Albokari ◽  
SM Alzahrani ◽  
AS Alsalman
Keyword(s):  
Dna Damage ◽  
Triticum Aestivum ◽  
Saudi Arabia ◽  
Gamma Irradiation ◽  
Gamma Rays ◽  
Triticum Aestivum L ◽  
Radiation Doses ◽  
Seedling Height ◽  
Height Data ◽  
Different Doses

Seeds of four local wheat (Triticum aestivum L.) cultivars, namely Hinta, Khaliji, Lokaimy and Qasime collected from different regions of Saudi Arabia were exposed to different doses of gamma rays 50-500 Gy to determine suitable doses for induction of mutation. It was observed that seedling height decreased with the increased dose of radiation in all cultivars. Radiosensitive curve originated from seedling height data resulted in 179, 225, 249 and 256 Gys as LD50 values for the cultivars Hinta, Khaliji, Qasime and Lokaimy, respectively. Based on LD50, as to minimize DNA damage and reduce undesirable mutations, radiation doses which lie between 200 and 250 Gy can be considered suitable for induction of mutation in cultivars Lokaimy, Khaliji and Qasime while between 150 and 200 Gy for cultivar Hinta DOI: http://dx.doi.org/10.3329/bjb.v41i1.11075 Bangladesh J. Bot. 41(1): 1-5, 2012 (June)

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