Cytology of intergeneric hybrids between Psathyrostachys and Elymus with Agropyron (Poaceae: Triticeae)

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 676-680 ◽  
Author(s):  
Kevin B. Jensen ◽  
Ira W. Bickford
Keyword(s):  
Chromosome Number ◽  
Chromosome Pairing ◽  
Intergeneric Hybrids ◽  
Agropyron Cristatum ◽  
Stainable Pollen ◽  
Meiotic Analysis ◽  
C Value ◽  
Elymus Species ◽  
I Cells ◽  
Metaphase I

This paper describes the cytogenetics and fertility of intergeneric hybrids of Psathyrostachys stoloniformis × Agropyron cristatum and two Elymus species, E. dentatus ssp. ugamicus and E. grandiglumis × A. cristatum. Bivalent frequencies of metaphase I cells in the F1 hybrid P. stoloniformis (NN) × Agropyron cristatum (PP) ranged from 0 to 4 per cell, with an average of 0.87 bivalent per cell and a c value of 0.07. The hybrid E. dentatus ssp. ugamicus (SSYY) × A. cristatum (PP) averaged 3.07 bivalents per cell and ranged from 0 to 7 with a c-value of 0.27. Bivalents were predominantly end to end associations. Meiotic analysis in E. grandiglumis (SSYYPP) × A. cristatum (PP) revealed an average of 6.84 bivalents per metaphase I cell with a c value of 0.73. This hybrid had a chromosome number of 2n = 30 rather than the expected 2n = 28. All hybrids had less than 1% stainable pollen and set no seed under open-pollination.Key words: chromosome pairing, meiosis.

Suppression of homologous pairing between chromosomes of A and B genomes of 4x and 6x wheats by Hordeum californicum Covas and Stebbins

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 8-11
Author(s):  
H. S. Balyan ◽  
G. Fedak
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Chiasma Frequency ◽  
Mother Cell ◽  
Triticum Turgidum ◽  
Regulatory Gene ◽  
Intergeneric Hybrids ◽  
Homologous Pairing ◽  
Meiotic Analysis ◽  
Hybrid Plants

Three hybrids of Triticum turgidum cv. Ma with Hordeum californicum × T. aestivum cv. Chinese Spring amphiploid were obtained at a frequency of 1.6% of the pollinated florets. Meiotic analysis of the hybrid plants revealed an average chiasma frequency per pollen mother cell ranging from 15.27 to 17.60. The lower than expected chromosome pairing in the hybrid plants was attributed to the suppression of pairing between homologous wheat chromosomes by pairing regulatory gene(s) in H. californicum.Key words: intergeneric hybrids, Hordeum californicum, Triticum turgidum, meiosis, chromosome pairing.

Interlocked bivalents in reconstructed metaphase I cells of bread wheat

1985 ◽  
Vol 75 (1) ◽  
pp. 85-92
Author(s):  
J.S. Heslop-Harrison ◽  
M.D. Bennett
Keyword(s):  
Triticum Aestivum ◽  
Light Microscopy ◽  
Bread Wheat ◽  
Chromosome Pairing ◽  
Light Microscope ◽  
Serial Sections ◽  
Ring Bivalents ◽  
Mother Cells ◽  
I Cells ◽  
Metaphase I

Complete reconstructions of all the bivalents were made from electron micrographs of serial sections through six pollen mother cells at metaphase I of meiosis in Triticum aestivum (hexaploid bread wheat). At least two of these metaphases contained interlocked pairs of bivalents. In one, two ring bivalents were interlocked, while in another a rod bivalent ran through the centre of a ring bivalent. Two other groups of bivalents were too closely appressed to allow separation into individual bivalents and may have contained interlocks. Meiosis in other anthers of the same plants examined by light microscopy was considered normal. The frequency of interlocking found was much higher than reported from light-microscope spreads. Not all interlocks in metaphase I cells need adversely affect meiosis, but knowledge of their regularity and form may facilitate understanding the processes of chromosome pairing.

Meiotic pairing in new hybrids of Hordeum procerum (6x) with H. parodii (6x) and Elymus virginicus (4x)

1986 ◽  
Vol 28 (3) ◽  
pp. 416-419 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrid ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Metaphase I

Hybrids of Hordeum procerum were readily produced with H. parodii (7.9%) and Elymus virginicus (14.3%). The average meiotic pairing per cell in the interspecific hybrid between H. procerum and H. parodii was 14.56 I + 12.19 II + 1.04 III, which indicated that the species have two genomes in common. In the hybrid between H. procerum and E. virginicus the average metaphase I configuration was 20.35 I + 6.86 II + 0.31 III indicating one common genome. Keywords: interspecific, intergeneric hybrids, chromosome pairing, Hordeum, Elymus.

CYTOGENETICS OF SOME NATURAL INTERGENERIC HYBRIDS BETWEEN ELYMUS AND AGROPYRON SPECIES

1981 ◽  
Vol 23 (1) ◽  
pp. 131-140 ◽  
Author(s):  
R. S. Sadasivaiah ◽  
J. Weijer
Keyword(s):  
Chromosome Pairing ◽  
Vegetative Growth ◽  
Interspecific Hybrids ◽  
Growth Habit ◽  
Intergeneric Hybrids ◽  
Homoeologous Relationships ◽  
Elymus Species

The occurrence of natural interspecific hybrids between Elymus and Agropyron species was detected and verified by cytomorphological studies. The hybrids were highly vigorous and resembled Elymus species in vegetative growth habit, although their spikes were sterile, and intermediate between the putative parents in morphology. Chromosome pairing in the hybrids was highly irregular with 14 to 28 univalents per cell. The formation of up to seven bivalents, with mean frequencies of 2.86 to 3.14 per cell in different hybrids, was attributed to homoeologous relationships existing between the genomes of E. innovatus (JJXX) and those of Agropyron species (SSHH).

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.

Intergeneric hybrids of Hordeum vulgare with Agropyron caninum and A. dasystachyum

1985 ◽  
Vol 27 (4) ◽  
pp. 387-392 ◽  
Author(s):  
George Fedak
Keyword(s):  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Meiotic Chromosome ◽  
Intergeneric Hybrids ◽  
Spindle Fibre ◽  
Chromosome Behavior ◽  
Paternal Parent ◽  
Agropyron Caninum

Hybrids were obtained by pollinating Hordeum vulgare cv. Betzes with Agropyron caninum (4x) and A. dasystachyum (4x) at frequencies of 1.4 and 6.1% of pollinated florets, respectively. The hybrids were sterile and phenotypically resembled the paternal parent, except for floret structure which was intermediate between the parental types. Chromosome pairing at meiosis was very low and thus provided no indication of homoeology between parental genomes. Abnormal meiotic chromosome behavior in meiocytes that occurred in sectors on the 'Betzes' × A. dasystachyum hybrid was attributed to abnormal spindle fibre function.Key words: intergeneric hybrids, Hordeum vulgare, Agropyron caninum, Agropyron dasystachyum.

CYTOLOGICAL STUDIES OF THE DEVELOPMENT OF METAPHASE I IN HYBRIDS BETWEEN TRITICUM TIMOPHEEVI ZHUK. AND T. DURUM DESF.

1961 ◽  
Vol 39 (1) ◽  
pp. 81-108 ◽  
Author(s):  
E. B. Wagenaar
Keyword(s):  
Late Stage ◽  
Developmental Stages ◽  
Progressive Increase ◽  
Cell Populations ◽  
Equatorial Plate ◽  
Triticum Timopheevi ◽  
Late Stages ◽  
I Cells ◽  
Metaphase I

In two hybrids between Triticum timopheevi Zhuk. and T. durum Desf., which have irregular meioses, metaphase I was subdivided into four developmental stages, early, medium, late, and very late. This subdivision was based on the presence in the anthers of other stages that occurred together with metaphase I. It was then discovered that in metaphase I cell populations there was a progressive increase of univalents from the early and medium stages to the very late stage. This phenomenon can be explained on the assumption that metaphase I is of shorter duration in the less irregular cells which pass into anaphase I earlier than the more irregular cells. As a consequence of this developmental phenomenon at metaphase I, the anaphase I and telophase I cells in the late anthers contained fewer lagging chromosomes than the anaphase I and telophase I cells in the very late anthers. Despite these numerical differences, the degrees of lagging were remarkably similar in both stages; approximately 70% of these univalents lagged at late and very late stages in both hybrids.During metaphase I many univalents of the irregular cells moved towards the equatorial plate, became oriented, and lagged at anaphase I and telophase I. It was found that the univalents of the least irregular cells accumulated somewhat faster at the plates than those of the more irregular cells.Considering the relationships between all of the available data, the hypothesis is advanced that when a certain number of univalents have accumulated at the equatorial plate a state of equilibrium is established and anaphase I is initiated. On the basis of this hypothesis an explanation of the trends observed at metaphase I is given.

Cytogenetics of Elymus caucasicus and Elymus longearistatus (Poaceae: Triticeae)

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 860-867 ◽  
Author(s):  
Kevin B. Jensen ◽  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrid ◽  
Intergeneric Hybrids ◽  
Cytological Analysis ◽  
Meiotic Behavior ◽  
Pseudoroegneria Spicata ◽  
Central Asian ◽  
Elymus Lanceolatus

Two accessions of Elymus caucasicus (Koch) Tzvelev and three accessions of Elymus longearistatus (Boiss.) Tzvelev were studied to determine the meiotic behavior and chromosome pairing in the two taxa, their interspecific hybrid, and their hybrids with various "analyzer" parents. Interspecific and intergeneric hybrids of the target taxa were obtained with the following analyzer species: Pseudoroegneria spicata (Pursh) A. Löve (2n = 14, SS), Pseudoroegneria libanotica (Hackel) D. R. Dewey (2n = 14, SS), Hordeum violaceum Boiss. &Hohenacker (2n = 14, HH) (= Critesion violaceum (Boiss. &Hohenacker) A. Löve), Elymus lanceolatus (Scribn. &Smith) Gould (2n = 28, SSHH), Elymus abolinii (Drob.) Tzvelev (2n = 28, SSYY), Elymus pendulinus (Nevski) Tzvelev (2n = 28, SSYY), Elymus fedtschenkoi Tzvelev (2n = 28, SSYY), Elymus panormitanus (Parl.) Tzvelev (2n = 28, SSYY), and Elymus drobovii (Nevski) Tzvelev (2n = 42, SSHHYY). Cytological analysis of their F1 hybrids showed that E. caucasicus and E. longearistatus were allotetraploids comprising the same basic genomes. Chromosome pairing in the E. caucasicus × P. libanotica hybrid demonstrated that the target taxa contained the S genome, based on 6.1 bivalents per cell. The lack of chromosome pairing, less than one bivalent per cell, in the E. longearistatus × H. violaceum hybrid showed that the H genome was absent. Increased pairing in the tetraploid and pentaploid hybrids when the Y genome was introduced indicated that the second genome in the two taxa was a segmental homolog of the Y genome. The S and Y genomes in E. caucasicus and E. longearistatus have diverged from each other and from those in many of the eastern and central Asian SY tetraploids.Key words: genome, meiosis, chromosome pairing, morphology, hybrid, Triticeae.

Sign in / Sign up

Export Citation Format

Share Document