Relationship in annual spceies of Medicago. III. The complex M. littoralis Rhode-M. truncatula Gaertn

1967 ◽  
Vol 15 (1) ◽  
pp. 35 ◽  
Author(s):  
JP Simon ◽  
AJ Millington
Keyword(s):  
Interspecific Hybrids ◽  
Seed Set ◽  
Chromosomal Rearrangements ◽  
Chromosome Translocation ◽  
Pollen Sterility ◽  
Multivalent Formation ◽  
Structural Differences ◽  
Intraspecific Hybrids ◽  
Adult Plants ◽  
Cytological Behaviour

A programme of interspecific hybridization, involving species from subsections Pachyspirae, Leptospirae, and Rotatae of section Spirocarpos, resulted in only one successful combination out of the 20 attempted. Viable hybrids were obtained with ease in crosses between different accessions of M. littoralis and M. truncatula. The morphology, fertility, and cytological behaviour of interspecific hybrids involving seven strains of M. truncatula and three strains of M. littoralis was compared with intraspecific hybrids of each species. With the exception of those with N.2829, which was differentiated from the other strains by one chromosome translocation, intraspecific hybrids of M. truncatula were fully fertile. Considerable pollen sterility and reduced seed set were observed in intraspecific crosses of M. littoralis, but there was no evidence of chromosomal rearrangements. The morphology of the hybrids between M. littoralis and M. truncatula was intermediate between the parents. Chlorophyll deficiency in seedlings and adult plants, dwarfism, and other morphological irregularities were observed in F2 plants. In some FT1s failure of pairing, multivalent formation at metaphase I, and other irregularities at meiosis indicated chromosome rearrangements. Up to three independent translocations and one inversion in the hybrid combinations and pronounced sterility were observed in both FT1s and FT2s. The pollen sterility of the hybrids could be explained in several instances by structural differences, but these do not account completely for the results obtained. Inheritance studies of three possible strain markers indicated simple monohybrid segregation in most intraspecific crosses, but in the interspecific and partially fertile intraspecific crosses, ratios were disturbed and phenotypes abnormal. The agronomic implications of these studies are discussed.

Variation in hybrid fertility among the disjunct populations and species of Sullivantia (Saxifragaceae)

1981 ◽  
Vol 59 (7) ◽  
pp. 1174-1180 ◽  
Author(s):  
Douglas E. Soltis
Keyword(s):  
Interspecific Hybrids ◽  
Chromosomal Rearrangements ◽  
Geographical Distance ◽  
Viable Seed ◽  
Hybrid Fertility ◽  
Gross Chromosomal Rearrangements ◽  
Disjunct Populations ◽  
Intraspecific Hybrids ◽  
Meiotic Aberrations ◽  
Made In

Crosses were made in all combinations between the four allopatric taxa of Sullivantia. Artificial hybridizations between any two Sullivantia plants almost invariably yielded viable seed that produced vigorous F1 hybrids. The observation that Sullivantia species are highly interfertile is in agreement with similar findings for many other north temperate perennial plants. In most cases, the average pollen fertility of interspecific hybrids is reduced compared with the fertility of parental plants and intraspecific hybrids. Since no meiotic aberrations were observed in hybrids, gross chromosomal rearrangements apparently are not responsible for the reductions in hybrid fertility. Within Sullivantia there is a general correlation between geographical distance separating parental populations and reduction in hybrid fertility. Similar correlations have been reported for several other angiospermous species, but the present study is the first report of such a geographical distance – fertility correlation within an entire genus.

Study on floral traits and seed setting in parental lines of hybrid rice during early ahu and kharif seasons

2018 ◽  
Vol 78 (3) ◽  
Author(s):  
Aradhana Phukan ◽  
P. K. Barua ◽  
D. Sarma ◽  
S. D. Deka
Keyword(s):  
Seed Set ◽  
Flag Leaf ◽  
Pollen Dispersal ◽  
Pollen Sterility ◽  
Leaf Length ◽  
Floral Traits ◽  
Opening Angle ◽  
Leaf Angle ◽  
Seed Setting ◽  
Parental Lines

Two CMS lines, IR 58025A and IR 68888A along with their maintainers and two fertility restorers, LuitR and IR 36R, were evaluated for flower and plant characters during early ahu (February-June) and kharif (July-November) seasons. IR 58025A showed longer stigmata and styles, and higher spikelet Length/Breadth (L/B) ratio while IR 68888A showed broader stigmata and wider glume opening angle in both the seasons. IR 68888A also exhibited higher pollen sterility during early ahu. IR 36R was characterized with broad anthers. LuitR showed longer and broader anthers with more pollen than others. Plant height, flag leaf length, flag leaf width and area were higher in IR 36R. Panicle exsertion was complete in pollen parents whereas it was 78-80% in CMS lines. The widest flag leaf angle was found in IR 58025B during early Ahu and in IR 36R during kharif. Kharif season was more favourable for growth of the plants with higher seed set percentage while floral traits of the CMS lines were better expressed in early Ahu. Manipulation of the seeding sequence of the parental lines in early Ahu is warranted for better seed set provided the seed crop escapes heavy premonsoon showers during reproductive stage. IR 68888A/LuitR was a good combination for pollen dispersal and seed setting.

Hybrid Zones and the Genetic Architecture of a Barrier to Gene Flow Between Two Sunflower Species

Genetics ◽  
1999 ◽  
Vol 152 (2) ◽  
pp. 713-727 ◽  
Author(s):  
Loren H Rieseberg ◽  
Jeannette Whitton ◽  
Keith Gardner
Keyword(s):  
Genetic Study ◽  
Genetic Architecture ◽  
Chromosomal Rearrangements ◽  
Pollen Sterility ◽  
Model Organisms ◽  
Hybrid Zones ◽  
Reproductive Barriers ◽  
Natural Hybrid ◽  
Generation Times ◽  
Helianthus Petiolaris

Abstract Genetic analyses of reproductive barriers represent one of the few methods by which theories of speciation can be tested. However, genetic study is often restricted to model organisms that have short generation times and are easily propagated in the laboratory. Replicate hybrid zones with a diversity of recombinant genotypes of varying age offer increased resolution for genetic mapping experiments and expand the pool of organisms amenable to genetic study. Using 88 markers distributed across 17 chromosomes, we analyze the introgression of chromosomal segments of Helianthus petiolaris into H. annuus in three natural hybrid zones. Introgression was significantly reduced relative to neutral expectations for 26 chromosomal segments, suggesting that each segment contains one or more factors that contribute to isolation. Pollen sterility is significantly associated with 16 of these 26 segments, providing a straightforward explanation of why this subset of blocks is disadvantageous in hybrids. In addition, comparison of rates of introgression across colinear vs. rearranged chromosomes indicates that close to 50% of the barrier to introgression is due to chromosomal rearrangements. These results demonstrate the utility of hybrid zones for identifying factors contributing to isolation and verify the prediction of increased resolution relative to controlled crosses.

INTERSPECIFIC HYBRIDS INVOLVING ALFALFA. VI. INEFFECTIVENESS OF ALLOPLOIDY IN INDUCTION FERTILITY IN MEDICAGO PIRONAE × M. DAGHESTANICA HYBRIDS

1971 ◽  
Vol 13 (3) ◽  
pp. 437-442 ◽  
Author(s):  
K. Lesins
Keyword(s):  
Interspecific Hybrids ◽  
Seed Set ◽  
Interspecific Cross ◽  
Pollen Grains ◽  
Colchicine Treatment ◽  
Plant Meiosis

Colchicine treatment of hybrids from the interspecific cross Medicago pironae Vis. × M. daghestanica Rupr. induced the formation of three tetraploid shoots, one with 2n = 29 and two with 2n = 32, in their somatic nuclei. Their flowers had 21, 44 and 62% plasma-filled pollen, respectively. No seed was obtained from these tetraploids after selfing and intercrossing more than 1,200 flowers, indicating the presence of a built-in fertility barrier between the two species.By applying pollen from the tetraploid hybrids to alfalfa (M. sativn L.) two trispecies hybrids with 2n = 34 and 30 chromosomcs were produced. The first had 32%, the second 22% plasma-filled pollen grains. On backcrossing to M. sativa, a higher seed set was obtained with pollen from the 2n = 34 plant than from the 2n = 30 plant. Meiosis in the 2n = 30 plant was abnormal. At MI multivalents were observed, indicating that chromosomal material may be interchanged between M. pironae-daghestanica and M. sativa. Approximately half the meiocytes at AI possessed lagging chromosomes and only 6% of secondary meiocytes at AII were without disturbances.

scholarly journals Isolation and Lack of Potential Mates may Threaten an Endangered Arid-Zone Acacia

2019 ◽  
Vol 110 (6) ◽  
pp. 738-745
Author(s):  
Cairo N Forrest ◽  
David G Roberts ◽  
Andrew J Denham ◽  
David J Ayre
Keyword(s):  
Reproductive Success ◽  
Seed Set ◽  
Arid Zone ◽  
Genotypic Diversity ◽  
Geographic Range ◽  
Landscape Scale ◽  
Reproductive Assurance ◽  
Threatened Plants ◽  
Self Fertilization ◽  
Adult Plants

Abstract Clonality may provide reproductive assurance for many threatened plants while limiting sexual reproductive success either through energetic tradeoffs or because clones are self-incompatible. Most stands of the Australian arid-zone plant Acacia carneorum, flower annually but low seed set and an absence of sexual recruitment now suggest that this species and other, important arid-zone ecosystem engineers may have low genotypic diversity. Indeed, our recent landscape-scale genetic study revealed that stands are typically monoclonal, with genets usually separated by kilometers. An inability to set sexually produced seed or a lack of genetically diverse mates may explain almost system-wide reproductive failure. Here, using microsatellite markers, we genotyped 100 seeds from a rare fruiting stand (Middle-Camp), together with all adult plants within it and its 4 neighboring stands (up to 5 km distant). As expected, all stands surveyed were monoclonal. However, the Middle-Camp seeds were generated sexually. Comparing seed genotypes with the single Middle-Camp genotype and those of genets from neighboring and other regional stands (n = 26), revealed that 73 seeds were sired by the Middle-Camp genet. Within these Middle-Camp seeds we detected 19 genotypes in proportions consistent with self-fertilization of that genet. For the remaining 27 seeds, comprising 8 different genotypes, paternity was assigned to the nearest neighboring stands Mallee and Mallee-West, approximately 1 km distant. Ironically, given this species’ vast geographic range, a small number of stands with reproductively compatible near neighbors may provide the only sources of novel genotypes.

scholarly journals TCL1 oncogene activation in preleukemic T cells from a case of ataxia- telangiectasia

Blood ◽  
1995 ◽  
Vol 86 (6) ◽  
pp. 2358-2364 ◽  
Author(s):  
MG Narducci ◽  
L Virgilio ◽  
M Isobe ◽  
A Stoppacciaro ◽  
R Elli ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ataxia Telangiectasia ◽  
Chromosomal Rearrangements ◽  
Chromosome Translocation ◽  
Peripheral Blood Lymphocytes ◽  
Genomic Locus ◽  
Chromosome Translocations ◽  
Inverted Duplication ◽  
Immunodeficiency Syndrome

The TCL1 oncogene on human chromosome 14q32.1 is involved in chromosome translocations [t(14;14)(q11;q32.1) and t(7;14)(q35;q32.1)] and inversions [inv14(q11;q32.1)] with TCR alpha/beta loci in T-cell leukemias, such as T-prolymphocytic (T-PLL). It is also involved in T- acute and -chronic leukemias arising in cases of ataxia-telangiectasia (AT), an immunodeficiency syndrome. Similar chromosomal rearrangements occur also in the clonally expanded T cells in AT patients before the appearance of the overt leukemia. We have analyzed the expression of TCL1 mRNA and protein in peripheral blood lymphocytes (PBLs) from four AT cases and from healthy controls. We found that the TCL1 gene was overexpressed in the PBLs of an AT patient with a large clonal T-cell population exhibiting the t(14;14) translocation but not in the lymphocytes of the other cases. Fluorescence in situ hybridization of the TCL1 genomic locus to lymphocyte metaphases from the AT patient with the T-cell clonal expansion showed that the breakpoint of the t(14;14) translocation lies within the TCL1 locus and is accompanied by an inverted duplication of the distal part of chromosome 14. These data indicate that TCL1 is activated in preleukemic clonal cells as a consequence of chromosome translocation involving sequences from the TCR locus at 14q11. Deregulation of TCL1 is the first event in the initiation of malignancy in these types of leukemias and represents a potential tool for clinical evaluation.

Cytological studies of Antipodean Teleogryllus species and their hybrids (Orthoptera: Gryllidae)

1969 ◽  
Vol 47 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Hai-Choo Lim ◽  
V. R. Vickery ◽  
D. K. McE. Kevan
Keyword(s):  
Chromosome Numbers ◽  
Interspecific Hybrids ◽  
Tabular Form ◽  
Field Crickets ◽  
Teleogryllus Commodus ◽  
Polyploid Cells ◽  
Black Field ◽  
Different Populations ◽  
Intraspecific Hybrids

Testes from nymphs of the last three instars of 10 populations of Australasian "black" field crickets, Teleogryllus commodus and T. oceanicus, and some of their hybrids, were examined to determine the number and morphology of their chromosomes. All populations gave counts of 2n = 27 in the male. The karyotypes of different populations and the hybrids are presented in tabular form with illustrations and idiograms. Some anomalies in chromosome numbers and structure were found, notably the occurrence of polyploid cells in the hybrids of T. commodus populations and in the interspecific hybrids.Chromosomal polymorphism was found to be common, except in some non-continental populations. Lampbrush-like chromosomes were found in metaphase 1 of interspecific hybrids and in the intraspecific hybrids of T. oceanicus. Achromatic gaps occur in T. oceanicus and in a population of T. commodus from Victoria, Australia.

Elucidation of intergenomic recombination and chromosome translocation: meiotic evidence from interspecific hybrids of Lilium through GISH analysis

Euphytica ◽  
2013 ◽  
Vol 194 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Songlin Xie ◽  
Munikote S. Ramanna ◽  
Richard G. F. Visser ◽  
Paul Arens ◽  
Jaap M. van Tuyl
Keyword(s):  
Interspecific Hybrids ◽  
Chromosome Translocation ◽  
Intergenomic Recombination ◽  
Gish Analysis

scholarly journals Male sterility in sunflower (Helianthus annuus L.) induced with new gametocidal agents

2019 ◽  
Vol 24 ◽  
pp. 26-32
Author(s):  
O. V. Bilynska ◽  
V. S. Lyutenko ◽  
P. G. Dulniev ◽  
V. P. Bezpartochna
Keyword(s):  
Bioorganic Chemistry ◽  
Male Sterility ◽  
Helianthus Annuus ◽  
Female Gametophyte ◽  
Seed Set ◽  
Pollen Sterility ◽  
Helianthus Annuus L ◽  
Investigation Methods ◽  
Negative Effect ◽  
Stock Solutions

Aim. Evaluation of the new gametocidal agents effect on pollen sterility and viability of female gamethophyte in sunflower was the main goal ofthe investigation. Methods. Sunflower florets were treated with nine newly synthesided in the Institute of Bioorganic Chemistry and Petrochemistry of NAS of Ukraine chemicals in concentrations ranged from 1.0 ml/l to 15.0 ml/l of stock solutions. Gibberellic acid (50 mg/l) was used as a control. The gametocidal effect on the pollen sterility was determined using seed-set after gametocide treatment and controlled self-pollination compared to untreated florets. Influence of gameticides on the female gametophyte viability was evaluated as seed-set after free cross-pollination. Results. It was revealed that DGK-2 and DGK-3 have a high gametocidal activity even at the lowest dose – 1 ml/l. DSK-10 appeared to be the most effective one at a dose of 5 ml/l. This treatment allowed us to achieve near-complete male sterility. Negative effect of gametocides on the female gametophyte was enhanced with increase in their concentrations. However, new gametocides had less negative effect compared to gibberellin in certain experimental variants. Conclusions. DGK-2, DGK-3 and DSK-10 are promising for further investigations on the chemical demasculation in sunflower for further hybridization on the fertile basis without mechanical anther removal. Keywords: sunflower, (Helianthus annuus L.), induced pollen sterility, gamitocidal agents, gibberellin, seed-set.

scholarly journals Hazelnut Pollen Phenotyping Using Label-Free Impedance Flow Cytometry

2020 ◽  
Vol 11 ◽  
Author(s):  
Lorenzo Ascari ◽  
Valerio Cristofori ◽  
Federico Macrì ◽  
Roberto Botta ◽  
Cristian Silvestri ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Pollen Viability ◽  
Central Italy ◽  
Chromosome Translocation ◽  
Pollen Sterility ◽  
Tree Canopy ◽  
Label Free ◽  
Lab On Chip ◽  
Pollen Hydration ◽  
Chip Technology

Impedance flow cytometry (IFC) is a versatile lab-on-chip technology which enables fast and label-free analysis of pollen grains in various plant species, promising new research possibilities in agriculture and plant breeding. Hazelnut is a monoecious, anemophilous species, exhibiting sporophytic self-incompatibility. Its pollen is dispersed by wind in midwinter when temperatures are still low and relative humidity is usually high. Previous research found that hazelnut can be characterized by high degrees of pollen sterility following a reciprocal chromosome translocation occurring in some cultivated genotypes. In this study, IFC was used for the first time to characterize hazelnut pollen biology. IFC was validated via dye exclusion in microscopy and employed to (i) follow pollen hydration over time to define the best pre-hydration treatment for pollen viability evaluation; (ii) test hazelnut pollen viability and sterility on 33 cultivars grown in a collection field located in central Italy, and two wild hazelnuts. The accessions were also characterized by their amount and distribution of catkins in the tree canopy. Pollen sterility rate greatly varied among hazelnut accessions, with one main group of highly sterile cultivars and a second group, comprising wild genotypes and the remaining cultivars, producing good quality pollen. The results support the hypothesis of recurring reciprocal translocation events in Corylus avellana cultivars, leading to the observed gametic semi-sterility. The measured hazelnut pollen viability was also strongly influenced by pollen hydration (Radj2 = 0.83, P ≤ 0.0001) and reached its maximum at around 6 h of pre-hydration in humid chambers. Viable and dead pollen were best discriminated at around the same time of pollen pre-hydration, suggesting that high humidity levels are required for hazelnut pollen to maintain its functionality. Altogether, our results detail the value of impedance flow cytometry for high throughput phenotyping of hazelnut pollen. Further research is required to clarify the causes of pollen sterility in hazelnut, to confirm the role of reciprocal chromosome translocations and to investigate its effects on plant productivity.

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