Diploid perennial intergeneric hybrids in the tribe Triticeae. IV. Hybrids among Thinopyrum bessarabicum, Pseudoroegneria spicata, and Secale montanum

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 356-360 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Meiotic Chromosome ◽  
Embryo Rescue ◽  
Intergeneric Hybrids ◽  
Root Tip ◽  
Pseudoroegneria Spicata ◽  
Genome Phylogeny ◽  
Karyotype Analyses ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Secale Montanum

Diploid intergeneric hybrids among Thinopyrum bessarabicum, Pseudoroegneria spicata, and Secale montanum were synthesized with the aid of embryo rescue. Karyotype analyses of mitotic root-tip cells revealed that all satellited chromosomes in the J, S, and R genomes were present in their hybrid combinations, making it possible to identify these hybrids at the seedling stage. Spikes of these hybrids were intermediate to, but distinctly different from, those of the parental species. Meiotic chromosome associations at metaphase I in the pollen mother cells averaged 4.34 I + 2.77 rod II + 1.42 ring II + 0.24 III + 0.14 IV for P. spicata × T. bessarabicum; 11.05 I + 1.22 rod II + 0.04 ring II + 0.13 III + 0.01 IV for T. bessarabicum × S. montanum; and 12.98 I + 0.52 rod II + 0.01 III for P. spicata × S. montanum. These meiotic data suggest that the S genome of Pseudoroegneria and the J genome of Thinopyrum are more closely related to each other than they are with the R genome of Secale. The R genome is slightly closer to the J genome than to the S genome. Since these synthetic hybrids represent genomic combinations that may not exist in nature, their induced amphiploids should be created and evaluated.Key words: intergeneric hybrids, genome, phylogeny, Thinopyrum, Pseudoroegneria, Secale.

Diploid perennial intergeneric hybrids in the tribe Triticeae. III. Hybrids among Secale montanum, Pseudoroegneria spicata, and Agropyron mongolicum

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 80-84 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Key Words ◽  
Embryo Culture ◽  
Intergeneric Hybrids ◽  
Root Tip ◽  
Pseudoroegneria Spicata ◽  
Chromosome Homology ◽  
Tip Cells ◽  
Root Tip Cells ◽  
Secale Montanum ◽  
Tribe Triticeae

Four new intergeneric diploid hybrids were synthesized in the greenhouse with the aid of embryo culture. Hybrids of Pseudoroegneria spicata × Secale montanum and P. spicata ssp. inermis × S. montanum, both having the genome formula SR, averaged 12.97 I + 0.49 II + 0.01 III at metaphase I. The hybrids of Agropyron mongolicum × S. montanum, which have the PR genomes, had an average of 12.86 I + 0.51 II + 0.03 III + 0.004 IV. The hybrid (SP) between P. spicata ssp. inermis and Agropyron mongolicum had a mean configuration of 8.05 I + 2.86 II + 0.07 III + 0.01 IV. All hybrids had intermediate spike morphology, respective to their parents, and were sterile. Mitotic preparations of root-tip cells of these hybrids suggested that the chromosomes of different genomes were spatially separated. The meiotic pairings of these hybrids indicated that chromosome homology between the S and P genomes is higher than either the S and R or the P and R. Both SR and PR hybrids represent new genomic combinations. The SP hybrid is equivalent to the dihaploid of P. tauri. All of these hybrids should be of value for breeding and taxonomy. Key words: intergeneric hybrids, genome, Secale, Pseudoroegneria, Agropyron.

Progenies of Thinopyrum elongatum × Agropyron mongolicum

Genome ◽  
1987 ◽  
Vol 29 (5) ◽  
pp. 738-743 ◽  
Author(s):  
Richard R-C. Wang
Keyword(s):  
Embryo Rescue ◽  
Chromosome Elimination ◽  
Root Tip ◽  
Hybrid Necrosis ◽  
Genome Chromosome ◽  
Pollen Mother Cells ◽  
Close Phylogenetic Relationship ◽  
Mother Cells ◽  
Thinopyrum Elongatum ◽  
High Degree

With the aid of embryo rescue, both a monoploid and several hybrids were obtained from the cross Thinopyrum elongatum × Agropyron mongolicum. The monoploid was a result of gradual and eventually complete elimination of A. mongolicum chromosomes in the hybrid. About 95% of the root-tip cells, and nearly all of the pollen mother cells, had only the seven chromosomes of the Je genome of the maternal parent. Very little autosyndesis occurred between chromosomes within the Je genome. Extensive chromosome pairings were observed in one headed hybrid, averaging 6.42 I + 2.53 rod II + 0.85 ring II + 0.25 III + 0.02 IV at metaphase I in pollen mother cells, which revealed a high degree of chromosome homology between the two genomes and thus justifying the close phylogenetic relationship between the two species. All plants died from hybrid necrosis, some as seedlings and some after heading. The Je and P genomes in the accessions used in this study carry complementary genes for hybrid necrosis. Key words: hybrid (intergeneric), haploid, genome, chromosome elimination, meiosis.

Genome doubling and chromosome elimination with fragment recombination leading to the formation of Brassica rapa–type plants with genomic alterations in crosses with Orychophragmus violaceus

Genome ◽  
2007 ◽  
Vol 50 (11) ◽  
pp. 985-993 ◽  
Author(s):  
Min Liu ◽  
Zai-Yun Li
Keyword(s):  
Brassica Rapa ◽  
Embryo Rescue ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Aflp Analysis ◽  
Genetic Introgression ◽  
Orychophragmus Violaceus ◽  
Distant Hybridization ◽  
Genome Doubling ◽  
Mother Cells

In distant hybridization of plants, nonclassical hybrids with unexpected chromosome complements, chromosome elimination, and genetic introgression have been well documented. We obtained intergeneric hybrids between Brassica rapa , B. rapa var. chinensis, and another cruciferous species, Orychophragmus violaceus , following embryo rescue. Hybrids mainly displayed phenotypes of B. rapa, although certain O. violaceus or novel characteristics also appeared. Variable numbers of chromosomes were observed in somatic cells in the roots of plantlets on medium and in ovaries and pollen mother cells (PMCs). However, higher numbers were recorded in the roots. GISH revealed that the majority of ovary cells and PMCs contained 20 chromosomes of B. rapa with or without individual O. violaceus chromosomes or fragments added or introgressed. AFLP analysis showed that fragments deleted from the B. rapa genome were much more frequent than novel and O. violaceus fragments. The mechanisms involved genome doubling and successive elimination of O. violaceus chromosomes accompanied by fragment recombination and introgression, producing B. rapa–type plants with modified genetic constitutions and phenotypes.

Enhanced meiotic chromosome pairing in intergeneric hybrids between Triticum aestivum and diploid Inner Mongolian Agropyron

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 98-102 ◽  
Author(s):  
Qin Chen ◽  
Joseph Jahier ◽  
Yvonne Cauderon
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Inner Mongolia ◽  
Meiotic Chromosome ◽  
Embryo Rescue ◽  
Genetic System ◽  
Intergeneric Hybrids ◽  
B Chromosomes ◽  
Meiotic Pairing ◽  
Reciprocal Hybrids

Triticum aestivum cv. Chinese Spring (2n = 6x = 42, ABD genomes) was crossed with diploid Inner Mongolian Agropyron Gaertn. species A. cristatum and A. mongolicum and reciprocal hybrids between them (2n = 2x = 14, P genome, with or without B chromosomes). Intergeneric hybrids with 2n = 27, 28, 32, and 33 chromosomes were produced by the aid of embryo rescue. The extra chromosomes in two hybrids were assumed to be B chromosomes transmitted by the male Agropyron parent. Average meiotic pairing in the euploid hybrid with 28 chromosomes was 14.38 univalents + 4.92 bivalents + 1.26 trivalents. This level of pairing higher than expected was likely due to homeologous associations between wheat chromosomes. This data indicates that the P genome of diploid as well as tetraploid Agropyron originating from Inner Mongolia possess a genetic system interfering with 5B homoeologous restricting system of wheat.Key words: intergeneric hybrids, Triticum aestivum, diploid Agropyron species, chromosome pairing.

An advanced generation of Aranda orchids

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 608-611 ◽  
Author(s):  
Y. H. Lee ◽  
F. Y. Tham
Keyword(s):  
Somatic Chromosome ◽  
Intergeneric Hybrids ◽  
Root Tip ◽  
Chromosome Counts ◽  
Pollen Mother Cells ◽  
Mother Cells ◽  
Tip Cells ◽  
Somatic Chromosome Numbers ◽  
Root Tip Cells ◽  
Advanced Generation

Aranda orchids are a group of artificially bred intergeneric hybrids between member species (2n = 38) of two natural genera, Vanda and Arachnis, of Orchidaceae. Nine second generation Aranda cultivars were selected for analysis of somatic chromosome numbers, meiotic behaviour, and sporad formation. Eight of the cultivars were derived from Aranda × Vanda crosses and one from an Aranda × Aranda cross. Chromosome counts of their root tip cells showed that eight of them contained 2n = 3x = 57 chromosomes each, presumably resulting from unreduced eggs of the Aranda parent fertilized by haploid Vanda pollen. The ninth revealed 2n = 2x = 38 chromosomes. Pollen mother cells of eight of the cultivars (2n = 3x = 57) commonly formed more than 10 bivalents, presumably between homologous Vanda chromosomes, as well as many univalents, mainly of Arachnis chromosomes. Only 8–10 bivalents were observed in pollen mother cells of the ninth cultivar (2n = 2x = 38). All the cultivars formed a range of dyads containing unreduced microspores. Two mechanisms are proposed for the origin of these dyad sporads.Key words: Aranda orchids, intergeneric hybrids, cytology.

Cytogenetic analyses of intergeneric hybrids between barley and nine species of Elymus

Genome ◽  
2008 ◽  
Vol 51 (11) ◽  
pp. 897-904 ◽  
Author(s):  
N.-S. Kim ◽  
G. Fedak ◽  
F. Han ◽  
W. Cao
Keyword(s):  
Wild Species ◽  
Meiotic Chromosome ◽  
Abiotic Stress Tolerance ◽  
Chromosome Analysis ◽  
Intergeneric Hybrids ◽  
Biotic And Abiotic Stress ◽  
Crop Species ◽  
Barley Cultivars ◽  
Bivalent Formation ◽  
Gish Analysis

Wild species in the Triticeae tribe are very valuable resources for agronomic improvement in cereal crop species. Intergeneric hybrids were produced between several barley cultivars and perennial species in the genera Elymus , Thinopyrum , and Pseudoroegneria . Caryopsis formation and subsequent plantlet regeneration from embryo culture were variable depending on the hybrid combinations. Chromosome numbers and hybrid identity were confirmed by GISH analysis on the somatic cells of the hybrids. While the hybrids showed very robust vegetative growth and exceeded the parental spikes in size, their floral morphologies resembled that of the wild species. Meiotic chromosome analysis revealed that the bivalent formation frequency per cell ranged from 0.06 in Hordeum vulgare ‘Betzes’ × Elymus curvatus to 3.0 in Elymus humidus  × H. vulgare ‘Manley’. By GISH analysis on the meiocytes of the hybrid E. humidus × ‘Manley’, the frequency of autosyndetic bivalents exceeded the allosyndetic bivalent formation, which gave an insight into the genome constitution of E. humidus as an autoallohexploid species. Regardless of the low allosyndetic chromosome pairing between barley and E. humidus, this combination may be useful for further input, since E. humidus is known to carry many valuable genes for biotic and abiotic stress tolerance.

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.

scholarly journals B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

2017 ◽  
Vol 11 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Manoj K. Dhar ◽  
Gurmeet Kour ◽  
Sanjana Kaul
Keyword(s):  
B Chromosome ◽  
Unreduced Gametes ◽  
Molecular Techniques ◽  
Root Tip ◽  
Genetic Constitution ◽  
Preferential Transmission ◽  
Female Sex ◽  
Process Formation ◽  
Plantago Lagopus ◽  
Mother Cells

Plantagolagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes.

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.

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