TRISOMIC PROGENY FROM INTERSPECIFIC HYBRIDS BETWEEN HELIANTHUS MAXIMILIANI AND H. ANNUUS

1982 ◽  
Vol 24 (4) ◽  
pp. 375-384 ◽  
Author(s):  
Ernest D. P. Whelan
Keyword(s):  
High Frequency ◽  
Pollen Fertility ◽  
Interspecific Hybrids ◽  
Extra Chromosome ◽  
Chromosome Elimination ◽  
Perennial Species ◽  
Two Generations ◽  
Pollen Shed

Interspecific hybrids between the diploid (2n = 34) perennial species Helianthus maximiliani Schrad. and wild H. annuus L. (2n = 34) had multivalents in meiosis. Consecutive backcrossing of the hybrids by the open-pollinated sunflower (H. annuus L.) cv. 'Saturn' resulted in rapid normalization of meiosis. However, some plants with highly modified anthers occurred and such plants were found to be diploid, whereas many plants with normal anthers and pollen shed were trisomic (2n + 1). Trisomics were first observed in two of three progenies after two crosses by 'Saturn'. Further backcrossing of trisomic females for two generations indicated about 50% megagametophyte transmission of the extra chromosome in one line and 10% in two others. Plants with a high frequency of 17 bivalents and a univalent in diplotene-MI had a higher frequency of chromosome elimination in subsequent division stages and a lower frequency of megagametophyte transmission of the extra chromosome, compared to plants having a high frequency of 16 bivalents and a trivalent. Elimination of the extra chromosome was correlated with increased pollen fertility. Primary interchange or tertiary trisomics were implicated by meiotic and fertility observations but were not identified as to type.

scholarly journals The asymmetry of female meiosis reduces the frequency of inheritance of unpaired chromosomes

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Daniel B Cortes ◽  
Karen L McNally ◽  
Paul E Mains ◽  
Francis J McNally
Keyword(s):  
Caenorhabditis Elegans ◽  
X Chromosome ◽  
High Frequency ◽  
Germ Line ◽  
Extra Chromosome ◽  
Polar Body ◽  
Contractile Ring ◽  
Female Meiosis ◽  
Random Segregation ◽  
The Asymmetry

Trisomy, the presence of a third copy of one chromosome, is deleterious and results in inviable or defective progeny if passed through the germ line. Random segregation of an extra chromosome is predicted to result in a high frequency of trisomic offspring from a trisomic parent. Caenorhabditis elegans with trisomy of the X chromosome, however, have far fewer trisomic offspring than expected. We found that the extra X chromosome was preferentially eliminated during anaphase I of female meiosis. We utilized a mutant with a specific defect in pairing of the X chromosome as a model to investigate the apparent bias against univalent inheritance. First, univalents lagged during anaphase I and their movement was biased toward the cortex and future polar body. Second, late-lagging univalents were frequently captured by the ingressing polar body contractile ring. The asymmetry of female meiosis can thus partially correct pre-existing trisomy.

Biparental Chromosome Elimination in Artificial Interspecific Hybrids of Pennisetum purpureum and Pennisetum glaucum

Crop Science ◽  
2013 ◽  
Vol 53 (5) ◽  
pp. 1917-1924 ◽  
Author(s):  
Larissa Fonseca Andrade-Vieira ◽  
Gabriela Barreto dos Reis ◽  
Giovana Augusta Torres ◽  
Ana Rafaela Oliveira ◽  
Ana Christina Brasileiro-Vidal ◽  
...  
Keyword(s):  
Interspecific Hybrids ◽  
Pennisetum Glaucum ◽  
Chromosome Elimination ◽  
Pennisetum Purpureum

Orderly arrangement of the chromosomes within barley genomes of chromosome-eliminating Hordeum lechleri × barley hybrids

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 225-236 ◽  
Author(s):  
Ib Linde-Laursen ◽  
Roland von Bothmer
Keyword(s):  
Key Words ◽  
Interspecific Hybrids ◽  
Chromosome Elimination ◽  
The Other ◽  
Barley Chromosome ◽  
Chromosome Variation ◽  
Varietal Differences ◽  
C Banding ◽  
Orderly Arrangement

One-hundred and nineteen progeny plants of crosses between one Hordeum lechleri (2n = 6x = 42) accession and the barley varieties 'Wong' and 'Igri' comprised 54 euploids (2n = 28), 8 hyperploids (2n = 29), 46 hypoploids (2n = 22 - 27), and 11 polyhaploids (2n = 21). Giemsa C-banding showed most interplant chromosome variation to be caused by elimination or, more seldom, duplication of barley chromosomes. The chromosomes of 'Wong' were preferentially lost in the order, 1H-4H-5H-3H-7H-2H-6H (5-4-7-3-1-2-6); those of 'Igri' in the order, 1H-3H or 6H-7H or 5H or 4H-2H (5-3 or 6-1 or 7 or 4-2), indicating different patterns of elimination. Over years chromosome elimination may be continuous. Hypoploid genomes of 'Wong' had the chromosomes arranged in the order, 1H-5H-2H-6H-7H-3H-4H (5-7-2-6-1-3-4), with a discontinuity between chromosomes 1H(5) and 4H(4); whereas in 'Igri' the order was (1H)-5H-2H-4H-7H-6H-3H-(1H) ((5)-7-2-4-1-6-3-(5)) with a discontinuity at 1H(5), indicating varietal differences. The patterns of barley chromosome elimination may be derived from chromosome orders. Elimination starts with a chromosome at the discontinuity, continues with the chromosome at the other end of the order, and proceeds more or less alternately towards the middle. In hybrids including 'Wong', duplication affected the two chromosomes situated at either end of barley chromosome order. A few older hybrids with 2n = 21 had three or four H.lechleri chromosomes substituted for as many barley chromosomes suggesting homoeology. Our observations support the hypothesis of an orderly arrangement of the chromosomes within genomes (Bennett 1981), but they do not agree with the idea of one 'natural karyotype' for each species (Bennett 1984b).Key words: Hordeum, interspecific hybrids, C-banding, chromosome elimination, chromosome order.

Effect of the fungicide phosphite on pollen fertility of perennial species of the Eucalyptus marginata forest and northern sandplains of Western Australia.

2002 ◽  
Vol 50 (6) ◽  
pp. 769 ◽  
Keyword(s):  
Western Australia ◽  
Pollen Fertility ◽  
Perennial Species ◽  
The South ◽  
Jarrah Forest ◽  
Eucalyptus Marginata ◽  
South West ◽  
Run Off

The fungicide phosphite was shown to affect pollen fertility in a range of perennial species from the south-west of Western Australia. Phosphite was applied to perennial species of the jarrah (Eucalyptus marginata) forest by spraying to run-off with 2.5, 5 and 10 g L–1 phosphite in either autumn or spring. Pollen fertility of Dryandra sessilis was reduced by phosphite for up to 35 and 60 weeks after spraying in spring or autumn, respectively. Trymalium ledifolium pollen fertility was reduced by phosphite 38 and 61 weeks after spraying in spring or autumn, respectively. Lasiopetalum floribundum was less affected with a reduction in pollen fertility being observed for up to 3 weeks after spraying in spring. Other perennial understorey species of the jarrah forest, Adenanthos barbiger, Boronia cymosa, Hovea elliptica and Phyllanthus calycinus were also shown to have reduced pollen fertility after treatment in autumn or spring, as did Comesperma calymega, Eremaea astrocarpa and Hibbertia hypericoides, species of the northern sandplains when sprayed in summer.

Design of a miniature modular inchworm robot with an anisotropic friction skin

Robotica ◽  
2018 ◽  
Vol 37 (3) ◽  
pp. 521-538 ◽  
Author(s):  
Wael Saab ◽  
Peter Racioppo ◽  
Anil Kumar ◽  
Pinhas Ben-Tzvi
Keyword(s):  
High Frequency ◽  
Experimental Validation ◽  
Anisotropic Friction ◽  
Confined Spaces ◽  
Model And Simulation ◽  
Body Dynamics ◽  
Two Generations ◽  
Simulation Results ◽  
Multi Body ◽  
Friction Analysis

SUMMARYThis paper presents the design, analysis, and experimental validation of a miniature modular inchworm robot (MMIR). Inchworm robots are capable of maneuvering in confined spaces due to their small size, a desirable characteristic for surveillance, exploration and search and rescue operations. This paper presents two generations of the MMIR (Version 1—V1 and Version 2—V2) that utilize anisotropic friction skin and an undulatory rectilinear gait to produce locomotion. This paper highlights design improvements and a multi-body dynamics approach to model and simulate the system. The MMIR V2 incorporates a slider-crank four-bar mechanism and a relative body revolute joint to produce high-frequency relative translation and rotation to increase forward velocity and enable turning capabilities. Friction analysis and locomotion experiments were conducted to assess the systems performance on various surfaces, validate the dynamic model and simulation results, and measure the maximum forward velocity. The MMIR V1 and V2 were able to achieve maximum forward velocities of 12.7 mm/s and 137.9 mm/s, respectively. These results are compared to reported results of similar robots published in the literature.

scholarly journals Meiotic analysis in induced tetraploids of Brachiaria decumbens Stapf

2011 ◽  
Vol 11 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Carine Simioni ◽  
Cacilda Borges do Valle
Keyword(s):  
Chromosome Segregation ◽  
Pollen Fertility ◽  
Interspecific Hybrids ◽  
Somatic Chromosome ◽  
Breeding Program ◽  
Meiotic Behavior ◽  
Brachiaria Decumbens ◽  
Meiotic Analysis ◽  
Chromosome Duplication

The meiotic behavior of three tetraploid plants (2n=4x=36) originated from somatic chromosome duplication of sexually reproducing diploid plants of Brachiaria decumbens was evaluated. All the analyzed plants presented abnormalities related to polyploidy, such as irregular chromosome segregation, leading to precocious chromosome migration to the poles and micronuclei during both meiotic divisions. However, the abnormalities observed did not compromise the meiotic products which were characterized by regular tetrads and satisfactory pollen fertility varying from 61.36 to 64.86%. Chromosomes paired mostly as bivalents in diakinesis but univalents to tetravalents were also observed. These studies contributed to the choice of compatible fertile sexual genitors to be crossed to natural tetraploid apomicts in the B. decumbens by identifying abnormalities and verifying pollen fertility. Intraespecific crosses should reduce sterility in the hybrids produced in the breeding program of Brachiaria, a problem observed with the interspecific hybrids produced so far.

HYBRIDIZATION BETWEEN ANNUAL AND PERENNIAL DIPLOID SPECIES OF HELIANTHUS

1978 ◽  
Vol 20 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Ernest D. P. Whelan
Keyword(s):  
Interspecific Hybrids ◽  
Diploid Species ◽  
Paracentric Inversion ◽  
Sterile Hybrid ◽  
Meiotic Behavior ◽  
Perennial Species ◽  
Annual Species ◽  
Normal Pollen

Hybrid characteristics, fertility and meiosis are described for the first interspecific hybrids to be obtained from crosses of the two perennial species (2n = 34) Helianthus giganteus and H. maximiliani with the annual species H. annuus (2n = 34). A single, highly pollen-sterile hybrid, H. giganteus × H. annuus cv. Krasnodarets, had abnormal meiosis with meiocytes containing univalents and multivalents. It was completely female sterile. The three H. giganteus × wild H. annus and four H. maximiliani × wild H. annuus hybrids had less than 5% normal pollen, and meiotic behavior suggested the presence of at least three interchanges and a paracentric inversion. Small quantities of seed were obtained by backcrossing with H. annuus cv. Saturn.

The cytology of hybrids between Hordeum vulgare and H. bulbosum revisited

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 486-494 ◽  
Author(s):  
Xu Jie ◽  
J. W. Snape
Keyword(s):  
Hordeum Vulgare ◽  
High Frequency ◽  
Interspecific Hybrids ◽  
Somatic Chromosome ◽  
Banding Technique ◽  
Chromosome 6 ◽  
Hordeum Bulbosum ◽  
Chromosome Counts ◽  
Low Frequencies ◽  
C Banding

Diploid and triploid interspecific hybrids were produced from crosses between four Hordeum vulgare varieties and two diploid and two tetraploid Hordeum bulbosum genotypes. These were studied cytologically using a C-banding technique as well as with conventional staining procedures. C-banding of mitotic preparations of the hybrids enabled all H. vulgare chromosomes to be identified individually, although only the satellited chromosome of H. bulbosum could be distinguished from the others of this genome. Most diploid hybrids had stable somatic chromosome constitutions (2n = 14), although 4 out of 39 plants had a mosaic constitution. Chromosome counts of triploid hybrids, however, revealed that about 40% of plants had a mosaic somatic constitution ranging from 7–22 chromosomes per cell, although 21-chromosome cells were at the highest frequency. Studies of meiosis in diploid hybrids showed that the frequency of pairing between H. vulgare and H. bulbosum chromosomes varied between different cross combinations and appeared to be mainly under the control of the H. bulbosum genome. C-banding revealed that H. vulgare chromosome 6 paired with the satellited chromosome of H. bulbosum. However, this latter chromosome was also absent in the majority of aneuploid cells and appeared to be the first to be eliminated. Meiosis in triploid hybrids was characterized by the presence of univalents, bivalents, and trivalents and, infrequently, higher order associations. Bivalents were formed mainly from pairing between H. bulbosum chromosomes alone, although trivalents were formed from pairing between two H. bulbosum and one H. vulgare chromosomes. All univalents, in cells that contained less than seven, were H. vulgare chromosomes. Overall, these results indicate that a high frequency of homoeologous allosyndesis can occur between the chromosomes of these two species, but it does depend on the H. bulbosum genotype used. It should be possible to introgress genes into H. vulgare through the use of H. bulbosum genotypes that have low frequencies of elimination and high chromosome pairing.Key words: Hordeum vulgare, H. bulbosum, C-banding, chromosome pairing.

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