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.

Absence of the J genome in Leymus species (Poaceae: Triticeae): evidence from DNA hybridization and meiotic pairing

Genome ◽  
1994 ◽  
Vol 37 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Richard R.-C. Wang ◽  
Kevin B. Jensen
Keyword(s):  
Dna Hybridization ◽  
Meiotic Chromosome ◽  
Dna Probe ◽  
Triploid Hybrid ◽  
Meiotic Pairing ◽  
Psathyrostachys Juncea ◽  
Chromosome Associations ◽  
Mother Cells ◽  
Thinopyrum Elongatum ◽  
Cell Chromosome

To test the presence of a J genome in the type species of Leymus, L. arenarius, its total genomic DNA and that of tetraploids L. mollis, L. salinus ssp. salmonis, L. ambiguus, L. chinensis, L. secalinus, L. alaicus ssp. karataviensis, and L. innovatus were probed with the 277-bp insert of pLeUCD2, which can hybridize with the J, S, and P but not with the N, R, V, Q, I, T, and ABD genomes. The DNA probe hybridized with PalI- or TaqI-digested total DNAs from Thinopyrum elongatum (JeJe diploid) and T. elongatum × Psathyrostachys juncea (JeN hybrid), but not with those from L. arenarius (NNNNXXXX octoploid) and all tetraploid Leymus species (NNXX). Attempts to cross diploid Thinopyrum and tetraploid Leymus species yielded only one triploid hybrid, T. elongatum × L. salinus ssp. salmonis. Meiotic chromosome associations at metaphase I of pollen mother cells in the triploid hybrid averaged 19.69 univalents, 0.64 bivalents, and 0.01 trivalents per cell. Chromosome pairings in the tetraploid hybrids of L. mollis × L. salinus ssp. salmonis, and the reciprocal cross, indicate that L. mollis and L. salinus ssp. salmonis shae the same genomic constitution. Both the DNA probe and genome analysis results confirm the absence of the J genome in the seven additional Leymus species tested. Meiotic data indicated that tetraploid Leymus species could not have the genome formula N1N1N2N2; thus their genome formulas should remain as NNXX until the source of X is identified.Key words: genome, Leymus, DNA probe, Southern blot, meiotic pairing, hybrid.

New intergeneric diploid hybrids among Agropyron, Thinopyrum, Pseudoroegneria, Psathyrostachys, Hordeum, and Secale

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 545-550 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Diploid Species ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Genome Chromosome ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Hybrid Genome ◽  
Genomic Relationships ◽  
The Mean ◽  
Thinopyrum Bessarabicum

Eight diploid intergeneric hybrids representing six genomic combinations were synthesized and meiotically analyzed. The SN hybrids of Pseudoroegneria spicata and P. spicata spp. inermis with Psathyrostachys juncea resembled the Pseudoroegneria species in that the spikes had a single spikelet per node. The spikes of all other hybrids were intermediate to those of their respective parents. The mean meiotic pairing pattern for two SN hybrids was 9.90 I + 1.74 rod II + 0.16 ring II + 0.07 III + 0.02 IV, which was equivalent to a mean arm-pairing frequency (c) of 0.16. When the results were averaged with a previously reported hybrid, the mean pairing in two hybrid plants of P. spicata × Thinopyrum bessarabicum (SJ genome combination) was 4.79 I + 3.24 rod II + 0.91 ring II + 0.18 III + 0.09 IV and c = 0.41. Of the JeS hybrids, mean pairing was 8.40 I + 2.30 rod II + 0.25 ring II + 0.13 III + 0.03 IV (c = 0.28) for T. elongatum × P. spicata and 6.98 I + 2.90 rod II + 0.39 ring II + 0.12 III + 0.02 IV (c = 0.28) for T. elongatum × P. spicata ssp. inermis. The JP hybrid of T. bessarabicum × Agropyron cristatum had 8.99 I + 2.11 rod II + 0.14 ring II + 0.13 III + 0.03 IV and c = 0.20. Pairing was lower in the new PH hybrids A. mongolicum × Hordeum californicum and HR hybrids H. californicum × Secale montanum: 12.20 I + 0.82 rod II + 0.05 III (c = 0.06) and 13.04 I + 0.44 rod II + 0.01 III (c = 0.03), respectively. These data contribute to the elucidation of the genomic relationships among diploid species of the perennial Triticeae.Key words: hybrid, genome, chromosome pairing, Triticeae.

scholarly journals Ecological Observations on Hybrid Populations of European Plethodontid Salamanders, Genus Speleomantes

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 285
Author(s):  
Enrico Lunghi ◽  
Fabio Cianferoni ◽  
Stefano Merilli ◽  
Yahui Zhao ◽  
Raoul Manenti ◽  
...  
Keyword(s):  
Body Condition ◽  
Parental Species ◽  
Stomach Contents ◽  
Trophic Niche ◽  
Natural Hybrid ◽  
Ecological Information ◽  
Total Length ◽  
Plethodontid Salamanders ◽  
The Future ◽  
First Time

Speleomantes are the only plethodontid salamanders present in Europe. Multiple studies have been performed to investigate the trophic niche of the eight Speleomantes species, but none of these studies included hybrid populations. For the first time, we studied the trophic niche of five Speleomantes hybrid populations. Each population was surveyed twice in 2020, and stomach flushing was performed on each captured salamander; stomach flushing is a harmless technique that allows stomach contents to be inspected. We also assessed the potential divergence in size and body condition between natural and introduced hybrids, and their parental species. Previously collected data on Speleomantes were included to increase the robustness of these analyses. In only 33 out of 134 sampled hybrid Speleomantes we recognized 81 items belonging to 11 prey categories. The frequency of empty stomachs was higher in females and individuals from natural hybrid populations, whereas the largest number of prey was consumed by males. We compared the total length and body condition of 685 adult salamanders belonging to three types of hybrids and three parental (sub)species. Three group of salamanders (one hybrid and two parental species) showed significantly larger size, whereas no difference in body condition was observed. This study provided novel ecological information on Speleomantes hybrid populations. We also provided insights into the potential divergence between hybrids and parental species in terms of size and body condition. We discuss our findings, and formulate several hypotheses that should be tested in the future.

Variation in induction of homoeologous pairing among chromosomes of 6x Hordeum parodii as a result of three triticale (×Triticosecale Wittmack) cultivars

1986 ◽  
Vol 28 (3) ◽  
pp. 420-425 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Control Mechanism ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Telomeric Heterochromatin ◽  
Triticosecale Wittmack ◽  
Heterochromatin Content

Intergeneric hybrids were obtained between Hordeum parodii Covas s.1. (6x) and three cultivars of triticale (×Triticosecale) at frequencies of 0.47 to 1.21% of pollinated florets. The triticale cultivars varied in their chromosome constitutions of the rye genome as well as the telomeric heterochromatin content of some of the rye chromosomes. The average chiasmata frequency per cell varied from 0.58 to 13.14 in different hybrid combinations. The differences in the chiasmata frequencies in the different hybrid combinations were attributed to a meiotic pairing control mechanism in H. parodii whose function was affected primarily by the rye chromosome constitutions of the triticale cultivars and to a lesser extent by the heterochromatin content of the rye chromosomes.Key words: hybrids (intergeneric), Hordeum, meiotic pairing control, chiasma.

The pattern of homoeologous recombination in triploid hybrids of Lolium multiflorum with Festuca pratensis

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 720-726 ◽  
Author(s):  
Z Zwierzykowski ◽  
A J Lukaszewski ◽  
B Naganowska ◽  
A Lesniewska
Keyword(s):  
Parental Species ◽  
Lolium Multiflorum ◽  
Festuca Pratensis ◽  
Meiotic Pairing ◽  
Homoeologous Recombination ◽  
Translocation Breakpoints ◽  
Zygotic Selection ◽  
Homoeologous Chromosomes ◽  
Pairing Initiation

Homoeologous chromosomes of Lolium-Festuca hybrids are capable of frequent meiotic pairing and recombination. The frequency and distribution of recombination was studied by genomic in situ hybridization in backcross progenies of reciprocal triploid hybrids of Lolium multiflorum with Festuca pratensis. Significant differences in the male transmission of the parental and translocated chromosomes were observed depending on the cytoplasm of the F1 hybrids and the ploidy level of the female test cross partner. The frequency of intergeneric translocations in the progeny indicated that, on average, there must have been at least 4.5 homoeologous arms paired in the F1 hybrids; the actual frequency might have been higher because of pre- or post-zygotic selection against the F. pratensis chromatin, which probably eliminated certain gametes with Festuca-Lolium translocations. Both parental species are known for localized distal chiasmata, but the intergeneric translocation breakpoints were distributed along the entire lengths of the chromosome arms. The change in the distribution of homoeologous recombination might have been related to different pairing initiation of homologues and homoeologues. It probably resulted from allocation of additional chiasmata to chromosome arms and produced a net increase in recombination.Key words: homoeologous exchanges, Lolium-Festuca, translocations, recombination.

Coenocytism, ameiosis, and chromosome diminution in intergeneric hybrids in the perennial Triticeae

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 766-775 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Intergeneric Hybrid ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Pollen Grain ◽  
Unreduced Gamete ◽  
Pollen Mother Cells ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Mother Cells ◽  
Pollen Grain Wall

Three different pathways of ameiotic microsporogenesis were observed in some intergeneric hybrids of the perennial Triticeae grasses. In one of the hybrids between Pseudoroegneria spicata ssp. inermis and Psathyrostachys juncea, pollen mother cells remained as premeiotic interphase cells when the pollen grain wall started to form. The microspores in such an ameiotic plant are presumably unreduced. Coenocyte formation coupled with ameiosis occurred in two hybrid plants of Psathyrostachys huashanica × Secale montanum. Less than 10% of the pollen mother cells had one nucleus. An average of 4.44 nuclei, ranging from 1 to 25 per pollen mother cell, was observed. The nuclei in coenocytes remained unfused when the pollen grain wall was formed. Nucleus splitting followed by cytoplasmic budding or cleavage, possibly a process of chromosome diminution or elimination, replaced meiotic divisions in most of the pollen mother cells in one plant of Leymus angustus × Hordeum bulbosum and two plants of Thinopyrum elongatum × Psathyrostachys juncea. It is evident that these meiotic abnormalities are under genetic control. Probable locations for these genes controlling these phenomena are suggested.Key words: coenocyte, ameiosis, chromosome diminution, chromosome elimination, microsporogenesis, unreduced gamete, polyploidy, intergeneric hybrid.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

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