Comparative chromosome pairing in triploids and diploids of perennial Triticeae

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Chromosome Association ◽  
Hordeum Bulbosum ◽  
Perennial Species ◽  
Chromosome Homology ◽  
Basic Genome ◽  
Genome Homology ◽  
First Time ◽  
Tribe Triticeae ◽  
Metaphase I

Meiotic data were obtained for the triploid hybrids Pseudoroegneria libanotica (2n = 14; SS) × P. stipifolia (2n = 28; SSSS), P. spicata (2n = 28; SSSS) × P. spicata (2n = 14; SS), P. strigosa (2n = 28; SSSS) × P. stipifolia (2n = 14; SS) for the first time. Additional polyhaploid plants of Critesion iranicum (2n = 42; HvHvHvHvHvHv) and triploid Hordeum bulbosum (HbHbHb) were also analyzed at metaphase I. The relationships between chromosome association at metaphase I in the autotriploids and in the corresponding diploids of perennial species in the tribe Triticeae were analyzed. The results corroborated the findings in an earlier study that the trivalent frequency in triploids having one or two basic genome(s) is positively correlated with the degree of genome homology in their corresponding diploids. Therefore, chromosome association at metaphase I in diploids is a function of chromosome homology and is a legitimate tool for studying genome relationships.Key words: genome, meiosis, autoploid, alloploid, homology, homoeology.

MODE OF POLLINATION OF PERENNIAL SPECIES OF THE TRITICEAE IN RELATION TO GENOMICALLY DEFINED GENERA

1990 ◽  
Vol 70 (1) ◽  
pp. 215-225 ◽  
Author(s):  
K. B. JENSEN ◽  
D. R. DEWEY ◽  
Y. F. ZHANG
Keyword(s):  
Seed Set ◽  
Biological Characteristics ◽  
Perennial Grasses ◽  
Perennial Species ◽  
Gene Manipulation ◽  
Germplasm Preservation ◽  
Cross Pollination ◽  
Foreign Pollen ◽  
First Time ◽  
Tribe Triticeae

The perennial grasses of the tribe Triticeae are among the world’s most valuable forages and provide an important gene source for wheat, barley, and rye breeders. Knowledge of mode of pollination (self-pollination versus cross-pollination) is essential to plant breeders, geneticists, and systematists involved in gene manipulation, germplasm preservation, and understanding the biological characteristics of taxa and their relatives. This paper reports for the first time on the mode of pollination of many perennial Triticeae grasses and evaluates the mode of pollination as it relates to the genomically defined genera of Dewey (1984). Self fertility was estimated by counting seed set on spikes that were enclosed in an isolation paper bag prior to anthesis to exclude foreign pollen. The latter genera can be grouped as follows: (1) those that are highly self-sterile, which include Agropyron, Psathyrostachys, Pseudoroegneria, and Elytrigia, averaging 1.2 selfed seeds per spike; (2) those variable in their degree of self-fertility, Thinopyrum, Leymus, and Pascopyrum, ranging from 0.0 to 46.1, 0.0 to 254.0, and 0.0 to 67.8 selfed seeds per spike, respectively; and (3) those genera highly self-fertile which include Elymus and Critesion, that average more than 30 self-seeds per spike. Taxa in group two show considerable variation within species as well as between species. In group three, the E. lanceolatus, C. brevisubulatum, and C. bulbosum complex are exceptions; their component taxa were highly self-sterile.Key words: Pollination, reproduction, Triticeae, genomes

Genome constitutions of Thinopyrum curvifolium, T. scirpeum, T. distichum, and T. junceum (Triticeae: Gramineae)

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 641-651 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Banding Pattern ◽  
Triploid Hybrid ◽  
Target Species ◽  
Banding Patterns ◽  
C Banding ◽  
Geographical Separation ◽  
Basic Genome ◽  
Karyotype Analyses ◽  
Metaphase I

The objective of this study is to elucidate genome constitutions of Thinopyrum curvifolium (Lange) D.R. Dewey, T. scirpeum (K. Presl) D.R. Dewey, T. distichum (Thunb.) A. Löve, and T. junceum (L.) A. Löve. Hybrids of T. sartorii (Boiss. &Heidr.) A. Löve with T. scirpeum and T. junceum, as well as the hybrid between T. curvifolium and Pseudoroegneria geniculata ssp. scythica (Nevski) A. Löve, were made and chromosome pairing at metaphase I was studied. The karyotype analyses of mitotic cells stained by aceto-orcein were conducted for both hybrids and the four target species. The Giemsa C-banding following acetocarmine staining was carried out for the above species and the triploid hybrid T. curvifolium × T. bessarabicum (Savul &Rayss) A. Löve. Meiotic data indicate that all target species have two sets of the basic genome J, but they behave like true allopolyploids because of bivalentization. Karyotypes of T. curvifolium and its triploid hybrid with T. bessarabicum indicate that T. curvifolium contains two different versions of the Jb genome, designated as Jb3 and Jb4, rather than two Je genomes as previously believed. Thinopyrum scirpeum and T. elongatum (4x) have similar karyotypes. Both are segmental allotetraploids carrying two forms of the Je genome. Their genome formulae are Je2 Je3 and Je1 Je3, respectively. Thinopyrum distichum has a karyotype similar to T. junceiforme, which has the Jb2 Je2 genome formula. However, the two species differ in C-banding patterns, reflecting their geographical separation. Thinopyrum junceum is a hexaploid with two pairs of Jb2 genomes and one pair of the Je2 genome, and it has a C-banding pattern similar to that of T. junceiforme, which has one pair each of the Jb2 and Je2 genomes.Key words: genome, meiosis, karyotype, C-banding, Triticeae, Thinopyrum.

NON-HOMOLOGOUS ASSOCIATIONS OF HAPLOID BARLEY CHROMOSOMES IN THE CYTOPLASM OF HORDEUM BULBOSUM L.

1973 ◽  
Vol 15 (1) ◽  
pp. 45-52 ◽  
Author(s):  
R. S. Sadasivaiah ◽  
K. J. Kasha
Keyword(s):  
Chromosome Pairing ◽  
Homologous Chromosome ◽  
Male Parent ◽  
Interspecific Crosses ◽  
Hordeum Bulbosum ◽  
Meiotic Behavior ◽  
Homologous Chromosome Pairing ◽  
Haploid Complement ◽  
Metaphase I

Haploids obtained from interspecific crosses between H. bulbosum (2n=14) and H. vulgare (2n=14) resembled the male parent (H. vulgare) with regard to vegetative and spike characteristics. The somatic chromosomes of these plants resembled those of the haploid complement (x=7) of the male parent H. vulgare. Thus, the haploids produced were considered androgenetic possessing the cytoplasm of H. bulbosum and the nucleus of H. vulgare. Detailed meiotic studies from pachytene to metaphase I in these haploids revealed non-homologous chromosome pairing, identical to that of haploids produced in the cytoplasm of H. vulgare. It was concluded that the influence, if any, of bulbosum cytoplasm on meiotic behavior of vulgare chromosomes is not different from that of vulgare cytoplasm.

Intergeneric hybrids between Thinopyrum and Psathyrostachys (Triticeae)

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 845-849 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Genome Analysis ◽  
Parental Species ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Green Leaves ◽  
Psathyrostachys Juncea ◽  
Basic Genome ◽  
Chromosome Associations ◽  
Thinopyrum Elongatum ◽  
First Time

Intergeneric hybrids were synthesized for the first time from the diploid crosses Thinopyrum elongatum (JeJe) × Psathyrostachys juncea (NjNj), T. elongatum × P. fragilis (NfNf), T. bessarabicum (JbJb) × P. huashanica (NhNh), and T. bessarabicum × P. juncea, as well as from a cross between the amphidiploid of T. bessarabicum × T. elongatum (JbJbJeJe) and P. juncea. Spikes of these hybrids are morphologically intermediate between those of the parental species. Double spikelets occurred occasionally at central nodes of the spikes. Glaucous blue leaves appeared in the F1 only in the cross T. bessarabicum × P. huashanica, suggesting that the gene(s) for glaucous blue leaves in T. bessarabicum is (are) recessive to a gene(s) for green leaves in P. juncea but is (are) dominant to that for yellowish green leaves in P. huashanica. Meiotic pairing at metaphase I in these diploid (JN) and triploid (JJN) hybrids revealed a very low level of homology between the basic J and N genome. Therefore, the J and N genomes are nonhomologous and justifiably represented by different genome symbols. The triploid hybrids exhibited a pattern of chromosome associations that substantiated the earlier conclusion that the genomes in T. bessarabicum and T. elongatum are two versions of a basic genome (J). These hybrids will be useful in genome analysis, forming new Leymus species with the J and N genomes and broadening the diversity in the genus Pascopyrum with the SHJN genomes.Key words: hybrid, Thinopyrum, Psathyrostachys, genome.

CHROMOSOME PAIRING IN TWO INTERSPECIFIC HYBRIDS OF TRIFOLIUM

1970 ◽  
Vol 12 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Chi-Chang Chen ◽  
Pryce B. Gibson
Keyword(s):  
Phylogenetic Relationship ◽  
Chromosome Pairing ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Triploid Hybrid ◽  
Close Phylogenetic Relationship ◽  
Metaphase I

Both Trifolium repens (2n = 32) and T. nigrescens (2n = 16) formed bivalents during meiosis. However, their triploid hybrid showed an average of 4.27 trivalents per microsporocyte at metaphase I. The frequency of trivalents in the hybrid between T. nigrescens and autotetraploid T. occidentale (2n = 32) was 5.69. The data are interpreted to indicate: (1) a possible autotetraploid origin of T. repens; and (2) a close phylogenetic relationship among T. repens, T. nigrescens and T. occidentale.

Chromosome pairing and potential for intergeneric recombination in some hypotetraploid somatic hybrids of Lycopersicon esculentum (+) Solanum tuberosum

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1032-1041 ◽  
Author(s):  
J. H. de Jong ◽  
A. M. A. Wolters ◽  
J. M. Kok ◽  
H. Verhaar ◽  
J. van Eden
Keyword(s):  
Solanum Tuberosum ◽  
Lycopersicon Esculentum ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Somatic Hybrids ◽  
Cytogenetic Study ◽  
Unreduced Gametes ◽  
Root Tip ◽  
Prophase I ◽  
Metaphase I

Three somatic hybrids resulting from protoplast fusions of a diploid kanamycin-resistant line of tomato (Lycopersicon esculentum) and a dihaploid hygromycin-resistant transformant of a monohaploid potato (Solanum tuberosum) line were used for a cytogenetic study on chromosome pairing and meiotic recombination. Chromosome counts in root-tip meristem cells revealed two hypotetraploids with chromosome complements of 2n = 46 and one with 2n = 47. Electron microscope analyses of synaptonemal complex spreads of hypotonically burst protoplasts at mid prophase I showed abundant exchanges of pairing partners in multivalents involving as many as eight chromosomes. In the cells at late pachytene recombination nodules were found in multivalents on both sides of pairing partner exchanges, indicating recombination at both homologous and homoeologous sites. Light microscope observations of pollen mother cells at late diakinesis and metaphase I also revealed multivalents, though their occurrence in low frequencies betrays the reduction of multivalent number and complexity. Precocious separation of half bivalents at metaphase I and lagging of univalents at anaphase I were observed frequently. Bridges, which may result from an apparent inversion loop found in the synaptonemal complexes of a mid prophase I nucleus, were also quite common at anaphase I, though the expected accompanying fragments could be detected in only a few cells. Most striking were the high frequencies of first division restitution in preparations at metaphase II/anaphase II, giving rise to unreduced gametes. In spite of the expected high numbers of balanced haploid and diploid gametes, male fertility, as revealed by pollen staining, was found to be negligible.Key words: synaptonemal complex, recombination, chromosome pairing, somatic hybrid, Lycopersicon esculentum (+) Solanum tuberosum.

Meiotic behaviour of induced autotetraploids in Triticum L.

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Yang Yen ◽  
Gordon Kimber
Keyword(s):  
Chromosome Pairing ◽  
Seed Set ◽  
Chromosome Association ◽  
Meiotic Behaviour ◽  
Meiotic Analysis

Colchicine-induced autotetraploids of Triticum speltoides, T. longissimum, T. sharonense, T. bicorne, T. uniaristatum, T. monococcum, and T. tauschii were all morphologically similar to but larger than their diploid forms. Seed set was lower than in the diploids except for the autotetraploid T. speltoides. Meiotic analysis showed fewer quadrivalents and more bivalents than would be expected in all of these autotetraploids. Arm-pair switch, indicated by complex trivalents and quadrivalents, was found and involved 0.1% of total chromosomes in T. umbellulatum, 0.5% in T. longissimum, 0.7% in both T. sharonense and T. tauschii, 6.3% in T. bicorne, and 15.3% in T. uniaristatum.Key words: meiosis, chromosome association, arm-pair switch, chromosome pairing, bivalentization.

scholarly journals A possible effect of B-chromosomes on metaphase I homologous chromosome association in rye

Heredity ◽  
1991 ◽  
Vol 67 (1) ◽  
pp. 123-128 ◽  
Author(s):  
M T Alvarez ◽  
A Fominaya ◽  
M Perez de la Vega
Keyword(s):  
Homologous Chromosome ◽  
B Chromosomes ◽  
Chromosome Association ◽  
Metaphase I
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