Genetic and cytogenetic analyses of the A genome of Triticum monococcum. I. Cytology, breeding behaviour, fertility, and morphology of induced autotetraploids

1985 ◽  
Vol 27 (1) ◽  
pp. 51-63 ◽  
Author(s):  
J. Kuspira ◽  
R. N. Bhambmani ◽  
T. Shimada
Keyword(s):  
Decisive Role ◽  
Leaf Size ◽  
Kernel Weight ◽  
Triticum Monococcum ◽  
Fertility Level ◽  
Breeding Behavior ◽  
Diploid Progenitor ◽  
Artificial Medium ◽  
A Genome ◽  
Cytogenetic Analyses

Autotetraploids were colchicine-induced in Triticum monococcum and, upon comparison to their diploid progenitor, possessed the following characteristics: (i) their cells were on the average 20.8% larger; (ii) plant height was reduced by 15% and tillering by 37.5%; (iii) spikes, 1000-kernel weight, pistil size (length (L)/weight (W), and leaf size (L/W) were 53.9, 51.2, 80/57.1, and 60/26.4% larger, respectively; and (iv) they were 12.4% earlier in heading. Observed mean numbers of univalents, bivalents, trivalents (linear, convergent, and indifferent coorientations), and quadrivalents (convergent and parallel alignments only) per microsporocyte at metaphase I were 0.62, 9.86, 0.23, and 1.74, respectively; 65.4% of all meiocytes possessed bivalents and (or) quadrivalents and produced balanced meiotic products; 34.6% also possessed univalents and (or) trivalents and, therefore, produced balanced and unbalanced meiotic products. The actual 70.9% balanced meiotic products falls within the calculated range of 65.4–81.3%. Our tetraploids breed true. Evidence and reasons for this are discussed. The fertility of our tetraploids was high (79.8%). Irregular chromosome behaviour during meiosis may play a decisive role in determining the fertility level. Genic factors may also be involved. Methods of improving fertility and whether chromosomal factors alone are responsible for tetraploid fertility levels are discussed. Mature seed from reciprocal 2n = 4x × 2n = 2x crosses was shrivelled because of endosperm collapse and did not germinate. Thus, embryo excision and culturing on artificial medium was required to obtain viable autotriploids.Key words: Triticum monococcum, autotetraploid, cytology, breeding behavior, fertility, morphology.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. III. Cytology, breeding behavior, fertility, and morphology of autotriploids

1986 ◽  
Vol 28 (5) ◽  
pp. 867-887 ◽  
Author(s):  
J. Kuspira ◽  
R. N. Bhambhani ◽  
R. S. Sadasivaiah ◽  
D. Hayden
Keyword(s):  
Diploid Species ◽  
Leaf Size ◽  
Kernel Weight ◽  
Triticum Monococcum ◽  
High Fertility ◽  
Breeding Behavior ◽  
Seed Fertility ◽  
A Genome ◽  
Cytogenetic Analyses

Mature triploid seed from reciprocal (2n = 4x × 2n = 2x) crosses in Triticum monococcum was minute and shrivelled because of endosperm collapse and therefore failed to germinate. This necessitated the excision of embryos from successful pollinations and their growth in vitro to ensure subsequent germination so as to obtain viable and vigorous autotriploids. A comparison of these triploids with their diploid and tetraploid progenitors revealed that cell size, kernel weight, and pistil size increased with an increase in ploidy level. However, unlike other species, optimum expression was observed in these triploids for plant height, tillering, size of spikes, number of spikelets/spike, and leaf size. Earliness, althoughenhanced in tetraploids relative to diploids, was delayed in the triploids. Mean numbers of univalents, bivalents, and trivalents per microsporocyte were 2.65, 2.60, and 4.38, respectively. Only chains (93.5%), which formed V-shaped metaphase I (MI) configurations, frying pan (5.0%), and Y-shaped (1.5%) trivalent associations occurred. On the average, two reciprocal exchanges occurred per bivalent and trivalent. Trivalents corriented randomly at MI. At anaphase I, all sets of three homologues segreated randomly to the two poles, lagging univalents always divided equationally, and only meiocytes with such chromosomes formed micronuclei. The reasons for similarities and differences in meiotic behaviour of T. monococcum triploids with those of other species are discussed. Confirmation of the conclusions drawn with respect to the cytology of the triploids was obtained from similar cytological observations with primary single trisomics. These triploids produced euploids, primary single trisomics as well as some double and triple trisomics all of which differed phenotypically from diploids. Triticum monococcum, like most diploid species, is highly intolerant of aneuploidy. Possible reasons for the differences in levels of tolerance of aneuploidy in species like T. monococcum and those like Petunia hybrida, which are highly tolerant of aneuploidy, are discussed. Pollen fertility was high and seed fertility was very low. Reasons for the latter as well as the high fertility in species that are highly tolerant of aneuploidy and allotriploids are discussed.Key words: Triticum monococcum, autotriploid, trisomic, cytology, breeding behavior, fertility, morphology.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. IV. Synaptonemal complex formation in autotetraploids

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 309-318 ◽  
Author(s):  
C. B. Gillies ◽  
J. Kuspira ◽  
R. N. Bhambhani
Keyword(s):  
Synaptonemal Complex ◽  
Theoretical Models ◽  
Triticum Monococcum ◽  
Pachytene Nucleus ◽  
Lateral Element ◽  
A Genome ◽  
Cytogenetic Analyses ◽  
The Difference ◽  
Quadrivalent Frequency ◽  
Metaphase I

Electron microscopy of synaptonemal complex spreads from autotetraploid Triticum monococcum (2n = 4x = 28) revealed a minimum mean of 3.59 multivalents per zygotene–pachytene nucleus. The range of values was from 1 to 6 multivalents per nucleus. Most of the multivalents were quadrivalents with single, medially located pairing partner switch points. Lateral element pairing switches, particularly the few multiple switches, were often accompanied by extensive asynapsis around the switch point. The synaptonemal complex multivalent frequency is considerably higher than the metaphase I quadrivalent frequency previously reported for the same material. Calculations of expected pachytene quadrivalent frequency from metaphase I data, using several published theoretical models, gave values that did not agree with the results obtained here. The difference between the multivalent frequencies at pachytene and metaphase I does not appear to be the result of a correction process. Instead, it could be caused by a combination of preferential pairing or crossing-over and the effects of the position of partner switches and asynapsis associated with switches. Key words: autotetraploid, multivalents, synaptonemal complex, pairing effects.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. IX. Cytological behaviour, phenotypic characteristics, breeding behaviour, and fertility of primary, double, and triple trisomics

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 565-579 ◽  
Author(s):  
N.-S. Kim ◽  
J. Kuspira
Keyword(s):  
Meiotic Chromosome ◽  
Triticum Monococcum ◽  
Low Fertility ◽  
Chromosome Behaviour ◽  
Primary Trisomics ◽  
Breeding Behaviour ◽  
Male Gametes ◽  
A Genome ◽  
Cytogenetic Analyses ◽  
Metaphase I

Cytogenetic studies in Triticum monococcum (2n = 2x = 14, AA) were initiated by generating a series of primary as well as double and triple trisomics from autotriploids derived from crosses between induced autotetraploids and a diploid progenitor. Analysis of meiotic chromosome behaviour revealed that, with the exception of primary trisomics for chromosome 7A, the chromosome present in triple dose in all other trisomics formed either a bivalent plus a univalent or a trivalent (always V shaped) at diakinesis – metaphase I in approximately equal proportions. Trisomics for chromosome 7A formed a bivalent plus a univalent or a trivalent in approximately a 1:2 ratio. About 99% of the anaphase I segregations in all the trisomics were seven to one pole and eight to the other, suggesting that primary trisomics in T. monococcum form n and n + 1 meiotic products in equal proportions. The double trisomics and triple trisomics formed 5 II + 2 III and 4 II + 3 III during metaphase I, respectively. A majority of the secondary meiocytes from the double and triple trisomics possessed unbalanced chromosome numbers. All the trisomics differed phenotypically from their diploid progenitors. Single primary trisomics for chromosomes 3A and 7A produced distinct morphological features on the basis of which they could be distinguished. The phenotypes of the double and triple trisomics deviated to a greater extent from that of diploids than those of the single trisomics. Less than 50% of the progeny of all primary trisomics were trisomics themselves. Trisomic progeny were not produced in diploid female × trisomic male crosses, indicating that functional n + 1 male gametes were not generated. Diploid as well as trisomic progeny were produced in the reciprocal crosses and upon self-fertilization of the trisomics. The average frequency of trisomic progeny was 9.9%. The fertility of primary trisomics ranged from 3.8% in trisomics for chromosome 1A to 40.6% in trisomics for chromosome 2A and was significantly less than that of diploids (99.6%). The breeding behaviour and low fertility of these trisomics make their maintenance and use in cytogenetic analyses difficult.Key words: Triticum monococcum, primary trisomics, double trisomics, triple trisomics, meiotic chromosome behaviour, phenotypes, breeding behaviour, fertility.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. VII. Telotrisomics and a ditelotetrasomic

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 849-854 ◽  
Author(s):  
Nam-Soo Kim ◽  
J. Kuspira
Keyword(s):  
Chromosome Segregation ◽  
Seed Set ◽  
Triticum Monococcum ◽  
Intermediate Phenotype ◽  
Telocentric Chromosome ◽  
Primary Trisomics ◽  
A Genome ◽  
Chromosome 5A ◽  
Cytogenetic Analyses ◽  
Growing Conditions

Telotrisomics (2n = 14 + t) were obtained from primary trisomics for chromosome 5A in Triticum monococcum. Subsequently, a ditelotetrasomic (2n = 14 + 2t) plant was obtained from these telotrisomics. C-banding analysis revealed that the extra telocentric chromosome in these aneuploids consisted of the short arm of chromosome 5A (triplo 5AS). Of 78 meiocytes studied at diakinesis and metaphase I in the telotrisomics, 20 (27.0%), 46 (58.9%), and 12 (14.1%) showed 6 II + 1 III,6 II + 3 I, and 7 II + 1 I configurations, respectively. Although the majority of the cells (84%) at anaphase I (AI) in the telotrisomics showed a 7–8 chromosome segregation, chromosome laggards were also observed. Their frequency (16%) was much higher than in primary trisomics. In a ditelotetrasomic plant, 14, 6, 8, and 4 cells of the 42 meiocytes studied showed 6 II + 1 IV, 7 II + 2 I, 6 II + 1 III + 1 I, and 8 II configurations, respectively. Approximately 62% of the meiocytes at AI in this plant showed an 8–8 chromosome segregation. Compared with primary trisomics and diploids, telotrisomics showed an intermediate phenotype for many of the characters studied. The telotrisomics headed earlier than primary trisomics, but later than diploids. The ditelotetrasomic headed much later than the telotrisomics. The ditelotetrasomic plant also showed very deleterious phenotypes such as slow growth and degeneration of tillers during the later stage of growth. An average of 51.7% of the florets of the telotrisomics exhibited seed set under greenhouse growing conditions. Fertility of the ditelotetrasomic plant on the other hand was very low (2.5%) under the same growing conditions.Key words: Triticum monococcum, C-bands, A genome.

scholarly journals Stripe rust resistance gene Yr34 (synonym Yr48) is located within a distal translocation of Triticum monococcum chromosome 5AmL into common wheat

2021 ◽  
Author(s):  
Shisheng Chen ◽  
Joshua Hegarty ◽  
Tao Shen ◽  
Lei Hua ◽  
Hongna Li ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Common Wheat ◽  
Stripe Rust ◽  
Rust Resistance ◽  
Triticum Monococcum ◽  
Rust Resistance Gene ◽  
Stripe Rust Resistance ◽  
Polyploid Wheat ◽  
Stripe Rust Resistance Gene ◽  
A Genome

AbstractKey messageThe stripe rust resistance geneYr34 was transferred to polyploid wheat chromosome 5AL from T. monococcumand has been used for over two centuries.Wheat stripe (or yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is currently among the most damaging fungal diseases of wheat worldwide. In this study, we report that the stripe rust resistance gene Yr34 (synonym Yr48) is located within a distal segment of the cultivated Triticum monococcum subsp. monococcum chromosome 5AmL translocated to chromosome 5AL in polyploid wheat. The diploid wheat species Triticum monococcum (genome AmAm) is closely related to T. urartu (donor of the A genome to polyploid wheat) and has good levels of resistance against the stripe rust pathogen. When present in hexaploid wheat, the T. monococcum Yr34 resistance gene confers a moderate level of resistance against virulent Pst races present in California and the virulent Chinese race CYR34. In a survey of 1,442 common wheat genotypes, we identified 5AmL translocations of fourteen different lengths in 17.5% of the accessions, with higher frequencies in Europe than in other continents. The old European wheat variety “Mediterranean” was identified as a putative source of this translocation, suggesting that Yr34 has been used for over 200 years. Finally, we designed diagnostic CAPS and sequenced-based markers that will be useful to accelerate the deployment of Yr34 in wheat breeding programs to improve resistance to this devastating pathogen.

scholarly journals Understanding the Evolution of Reptile Chromosomes through Applications of Combined Cytogenetics and Genomics Approaches

2019 ◽  
Vol 157 (1-2) ◽  
pp. 7-20 ◽  
Author(s):  
Janine E. Deakin ◽  
Tariq Ezaz
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Chromosome Analysis ◽  
Evolutionary Significance ◽  
Initial Report ◽  
Genomic Technologies ◽  
A Genome ◽  
Sand Lizard ◽  
Cytogenetic Analyses ◽  
Lacerta Agilis

Studies of reptile (nonavian reptiles) chromosomes began well over a century ago (1897) with the initial report on the description of sand lizard (Lacerta agilis) chromosomes. Since then, chromosome analysis in reptiles has contributed significantly to understanding chromosome evolution in vertebrates. Reptile karyotypes are also unique, as being the only vertebrate group where the majority of the species possess variable numbers of macro- and microchromosomes, which was first reported for iguanids and teiids in 1921. In addition, many reptiles have microchromosomes as sex chromosomes, highlighting their evolutionary significance, yet very little is known about their evolutionary origin and significance in shaping amniote genomes. Advances in genomic technologies in recent years have accelerated our capacity to understand how sequences are arranged within a genome. However, genomic and cytogenetic analyses have been combined for only 3 species to provide a deeper understanding of reptile chromosome evolution and sequence organization. In this review, we highlight how a combined approach of cytogenetic analysis and sequence analysis in reptiles can help us answer fundamental questions of chromosome evolution in reptiles, including evolution of microchromosomes and sex chromosomes.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. VI. Production and identification of primary trisomics using the C-banding technique

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 542-555 ◽  
Author(s):  
B. Friebe ◽  
N.-S. Kim ◽  
J. Kuspira ◽  
B. S. Gill
Keyword(s):  
Nucleolus Organizer ◽  
Triticum Monococcum ◽  
Banding Patterns ◽  
Primary Trisomics ◽  
Nucleolus Organizer Regions ◽  
C Banding ◽  
A Genome ◽  
Chromosome 5A ◽  
Triple Dose

Cytogenetic studies in Triticum monococcum (2n = 2x = 14) are nonexistent. To initiate such investigations in this species, a series of primary trisomics was generated from autotriploids derived from crosses between induced autotetraploids and diploids. All trisomics differed phenotypically from their diploid progenitors. Only two of the seven possible primary trisomic types produced distinct morphological features on the basis of which they could be distinguished. The chromosomes in the karyotype were morphologically very similar and could not be unequivocally identified using standard techniques. Therefore, C-banding was used to identify the chromosomes and trisomics of this species. Ag–NOR staining and in situ hybridization, using rDNA probes, were used to substantiate these identifications. A comparison of the C-banding patterns of the chromosomes of T. monococcum with those of the A genome in Triticum aestivum permitted identification of five of its chromosomes, viz., 1A, 2A, 3A, 5A, and 7A. The two remaining chromosomes possessed C-banding patterns that were not equivalent to those of any of the chromosomes in the A genome of the polyploid wheats. When one of these undesignated chromosomes from T. monococcum var. boeoticum was substituted for chromosome 4A of Triticum turgidum, it compensated well phenotypically and therefore genetically for the loss of this chromosome in the recipient species. Because this T. monococcum chromosome appeared to be homoeologous to the group 4 chromosomes of polyploid wheats, it was designated 4A. By the process of elimination the second undesignated chromosome in T. monococcum must be 6A. Analysis of the trisomics obtained led to the following conclusions. (i) Trisomics for chromosome 3A were not found among the trisomic lines analyzed cytologically. (ii) Primary trisomics for chromosomes 2A, 4A, 6A, and 7A were positively identified. (iii) Trisomics for the SAT chromosomes 1A and 5A were positively identified in some cases and not in others because of polymorphism in the telomeric C-band of the short arm of chromosome 1A. (iv) Trisomics for chromosome 7A were identified on the basis of their distinct phenotype, viz., the small narrow heads and small narrow leaves. Because rRNA hybridizes lightly to nucleolus organizer regions on chromosome 1A and heavily to nucleolus organizer regions on chromosome 5A, our results indicate that trisomics in line 50 carry chromosome 1A in triple dose and trisomics in lines 28 and 51 carry chromosome 5A in triplicate. Variable hybridization of the rDNA probe to nucleolus organizer regions on chromosomes in triple dose in lines 7, 20, and 28 precluded the identification of the extra chromosome in these lines. Cytogenetic methods for unequivocally identifying trisomics for chromosomes 1A and 5A are discussed. Thus six of the series of primary trisomics have been identified. Telotrisomic lines are also being produced.Key words: Triticum monococcum, trisomics, C-banding, Ag-NOR staining, in situ hybridization, rDNA probes, plant morphology.

scholarly journals Morpho-Agronomical and Nutritional Evaluation of Cultivated Einkorn Wheat (Triticum monococcum L. ssp. monococcum) Lines Sown in Autumn and Spring Seasons

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Servet Kefi ◽  
Orhan Kavuncu ◽  
Engin Bıyıklı ◽  
Ayten Salantur ◽  
Mehmet Emin Alyamaç ◽  
...  
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Correlation Coefficients ◽  
Grain Protein Content ◽  
Kernel Weight ◽  
Triticum Monococcum ◽  
Einkorn Wheat ◽  
Pests And Diseases ◽  
Neolithic Age ◽  
Different Seasons

Nowadays diploid einkorn wheat (Triticum monococcum L. ssp. monococcum), widely cultivated in the Neolithic age, has been reconsidered as the valuable genetic resource for breeding and organic farming due to its high resistance to pests and diseases, adaptation to harsh climates, ability to provide acceptable yields on poor soils even with low/without inputs and high nutritional values. In this research, local 45 cultivated einkorn lines, selected from 500 single rows planted by each single spikes collected from total 50 farmers’ fields in 34 villages of Kastamonu/Turkey, were evaluated in terms of their morpho-agronomical traits and nutritional characteristics during two sowing seasons, autumn 2017 and spring 2018. Einkorn lines sown in two different seasons showed significant variations for heading time, plant height, lodging susceptibility, spike length, number of spikelets per spike, gross grain yield, amount of glume, single kernel weight, kernel diameter, hardness index, grain protein content and the color (a, b, L) values of flour. Furthermore, most of the correlation coefficients between these characteristics were found to be significant. All lines showed “facultative” growth habit, flowering well when sown both in autumn and in spring. Although lines sown in autumn had more yields, the same lines sown in spring provided higher grain quality and more resistance to lodging due to having shorter stems. In order to enable sustainable future use of einkorn, further research is suggested for reduction of plant height to avoid lodging and improvement of grain yield to compete with modern high yielding wheat cultivars.  

scholarly journals Caracterization of Am –A genomes chromosomes in diploid wheat, polyploid wheat and triticales by marker cytogenetic

2021 ◽  
Author(s):  
Hammouda Bousbia Dounia ◽  
Benbelkacem Abdelkader
Keyword(s):  
Triticum Aestivum ◽  
Dna Sequences ◽  
Triticum Durum ◽  
Structural Heterogeneity ◽  
Triticum Monococcum ◽  
Diploid Wheat ◽  
Polyploid Wheat ◽  
Sixth Generation ◽  
A Genome ◽  
Wheat Hybrids

The distribution and Caracterization of constitutive heterochromatin in A-Am genomes of diploid wheat (progenitor), polyploid wheat (hybrids) and triticales (primary and secondary) are analyzed and compared by C-bands. The Comparison of zones rich in highly repeated DNA sequences marked by C bands on the all chromosomes of Am - A genomes revealed an important structural heterogeneity. Four chromosomes of Triticum monococcum (1Am-3Am-4Am-5Am) are almost similar to their homologues in wheat (Triticum durum , Triticum aestivum ) and triticale, by the presence or absence of C bands. Contrary to the chromosomes 2Am (rich in heterochromatin), 6Am-7Am (absence of C bands) show a great differentiation compared to their homologues of Triticum durum and Triticum aestivum and x-Triticosecale Wittmack. In the triticales, A genome chromosomes are richer in heterochromatin compared to theirs homologous of polyploid wheats. This is explained by a "genome shock The confrontation of C- bands genome (Triticum monococcum) with a C+ bands genome (durum wheat / or common wheat) produces an interspecific hybrid which at the sixth generation reveals C+ bands (triticales). The variations observed in our vegetal material indicated the existence of an intervarietal and interspecific heterochromatic polymorphism. The presence of B chromosomes in triticales, could be explained as a manifestation of their adaptation.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum L. V. Inheritance and linkage relationships of genes determining the expression of 12 qualitative characters

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 869-881 ◽  
Author(s):  
J. Kuspira ◽  
J. Maclagan ◽  
R. N. Bhambhani ◽  
R. S. Sadasivaiah ◽  
N.-S. Kim
Keyword(s):  
Triticum Aestivum ◽  
Genetic Variability ◽  
Major Gene ◽  
Morphological Characters ◽  
Triticum Monococcum ◽  
Chromosomal Mapping ◽  
Allelic Series ◽  
Einkorn Wheat ◽  
Breeding Lines ◽  
A Genome

Our investigation of 460 true-breeding lines confirms a long-standing observation that natural phenotypic and genetic variability in the diploid wheat Triticum monococcum L. is limited. The modes of inheritance of 12 morphological characters are discussed in light of the extensive information available on the genetics and cytogenetics of many of these characters in the related wheat Triticum aestivum. Analysis of data from appropriate crosses, complementation studies, and observations of phenotypes of F1s and F2s from crosses between lines expressing dominant traits indicate that each of these characters is determined by one major gene. A multiple allelic series exists at each of the Hg (glume pubescence) and Hn (node pubescence) loci. The genes for six of these characters fall into two closely linked groups. Genes Bg (glume colour) and Hg are the same distance apart as in Triticum aestivum, indicating that at least this segment of chromosome 1A has been highly or completely conserved since the origin of the polyploid wheats. The genes Sg (glume hardness), La (lemma awn length), Fg (false glume), and Lh (head type) are also very closely linked, with the outside markers being only 4 map units apart. The dominant and recessive alleles of genes determining these characters should serve as excellent markers for linkage and chromosomal mapping because of their complete penetrance and constant expressivity. Tentative assignments of genes and linkage groups identified in this investigation to specific chromosomes of T. monococcum have been made on the basis of known chromosomal locations of A genome genes in T. aestivum. The tentative assignments could be verified using a variety of genetic and cytogenetic approaches. It is suggested that a thorough study of the genetic heritage of einkorn wheat will require the use of induced mutants since natural genetic variability is low in this species.Key words: Triticum, characters, inheritance, linkage, mapping, A genome.

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