Meiotic restitution mechanisms and 2<i>n</i> pollen formation in a <i>Solanum tuberosum</i> dihaploid and in dihaploid × wild species hybrids*

Conicella, Clara; Genualdo, G.; Errico, A.; Frusciante, Luigi; Monti, L. M.

doi:10.1111/j.1439-0523.1996.tb00893.x

Cited by 13 publications

(4 citation statements)

References 25 publications

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“…It is well known that unreduced gametes or meiotic restitution is of predominant importance in polyploidization and speciation. This phenomenon has been reported in alfalfa (Pfeiffer and Bingham, 1983), barley (Finch and Bennet, 1979), potato (Conicella et al, 1996), and other species in Triticeae (Tiwari et al, 2008;Zhang et al, 2008).…”

Section: Discussionmentioning

confidence: 91%

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

Xie

Kang²,

Sparkes³

et al. 2013

Genet. Mol. Res.

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ABSTRACT. The dynamics of rye chromosomes during mitosis and meiosis was analyzed in a subset comprising 33 F 3 lines from the cross of wheat, Psathyrostachys huashanica amphiploid (AABBDDNsNs) and hexaploid triticale (AABBRR), as visualized by genomic in situ hybridization. The results indicated that 31 of the total lines contained 4-14 rye chromosomes. Twenty-eight combinations had more rye chromosomes than the F 1 hybrids, suggesting the occurrence of spontaneous quantitative increment. No P. huashanica chromosomes were detected in all of the combinations tested. Mitotic analysis showed that rye chromosomes progressed normally with the wheat counterparts without loss. However, abnormal meiosis was found in almost all lines. Similar progression between wheat and rye genomes appeared from interphase to metaphase I. It was at anaphase I that many rye univalents lagged behind those of wheat, followed by equational division. This resulted in the formation of chromosomal segments and micronuclei at telophase I or II. Micronuclei could also be generated from the immobilized univalents in the periphery of cells. Synapsis and translocations between wheat and rye genomes, chromosome bridges, and unreduced gametes were detected. Therefore, it is proposed that rye chromosome elimination may involve chromatid lagging, fragmentation and micronucleation, or the immobilization of certain univalents during meiosis instead of mitosis in the relatively advanced generations. This mechanism, together with spontaneous incremental increase of rye chromosome number, permitted the generation of various germplasms for wheat improvement.

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Section: Discussionmentioning

confidence: 91%

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

Xie

Kang²,

Sparkes³

et al. 2013

Genet. Mol. Res.

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“…Proper chromosome number reduction is produced when the two spindles adopt a perpendicular orientation in the second meiotic division, followed by cytokinesis to yield the four microspores. Disturbed arrangements such as fused spindles and parallel spindles generate a dyad with 2n nuclei while a tripolar spindle produce a triad containing two n and one 2n nuclei [ 77 , 78 , 79 , 80 ]. However, fused, parallel and tripolar spindles may appear in the same flower and probably represent different phenotypic expressions of the same cellular defect [ 79 , 80 , 81 , 82 ].…”

Section: Mechanisms and Frequency Of Wgd In Plantsmentioning

confidence: 99%

Genomic and Meiotic Changes Accompanying Polyploidization

Blasio

Prieto

Pradillo

et al. 2022

Plants

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Hybridization and polyploidy have been considered as significant evolutionary forces in adaptation and speciation, especially among plants. Interspecific gene flow generates novel genetic variants adaptable to different environments, but it is also a gene introgression mechanism in crops to increase their agronomical yield. An estimate of 9% of interspecific hybridization has been reported although the frequency varies among taxa. Homoploid hybrid speciation is rare compared to allopolyploidy. Chromosome doubling after hybridization is the result of cellular defects produced mainly during meiosis. Unreduced gametes, which are formed at an average frequency of 2.52% across species, are the result of altered spindle organization or orientation, disturbed kinetochore functioning, abnormal cytokinesis, or loss of any meiotic division. Meiotic changes and their genetic basis, leading to the cytological diploidization of allopolyploids, are just beginning to be understood especially in wheat. However, the nature and mode of action of homoeologous recombination suppressor genes are poorly understood in other allopolyploids. The merger of two independent genomes causes a deep modification of their architecture, gene expression, and molecular interactions leading to the phenotype. We provide an overview of genomic changes and transcriptomic modifications that particularly occur at the early stages of allopolyploid formation.

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“…The formation of abnormal sporads at telophase-I/II stages was found in all mutagen treatments except 200 Gy γ rays+0.02% SA in both varieties. Several workers have also reported the formation of dyads, triads, and polyads in Tuberosum [ 86 , 87 ] potato [ 88 ] and roses [ 89 ]. The lack of cytokinesis in meiosis II may be attributed to the formation of dyads with two diploid cells and triads with two haploid cells and one diploid cell [ 90 ].…”

Section: Discussionmentioning

confidence: 99%

Assessment of Bio-physiological damages and cytological aberrations in cowpea varieties treated with gamma rays and sodium azide

2023

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The assessment of mutagen induced biological damage forms an important study in determining the mutagenic potency and genotypic sensitivity, a vital aspect in mutation breeding programs. A prior assessment of lethal dose (LD50), mutagen induced biological damage (alterations in bio-physiological traits and frequency of cytological aberrations) is a prerequisite for determining an optimum mutagen dose in a successful mutation breeding experiment. Therefore, in a multi-year project of mutation breeding, two widely cultivated varieties of cowpea viz., Gomati VU-89 and Pusa-578, were treated with gamma (γ) rays and sodium azide (SA) doses. The results reflected a proportionate increase in bio-physiological damages with the increase in mutagenic doses and caused a substantial reduction in mean seed germination and seedling height. Different cytological aberrations such as cytomixis, univalents, chromosome stickiness, precocious separation, unequal separation, bridges, laggards, disturbed polarity, dyads, triads, and polyads were observed in both varieties. All the mutagen doses induced a broader spectrum of cytological aberrations with varying frequencies.

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Meiotic restitution mechanisms and 2n pollen formation in a Solanum tuberosum dihaploid and in dihaploid × wild species hybrids*

Cited by 13 publications

References 25 publications

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

Genomic and Meiotic Changes Accompanying Polyploidization

Assessment of Bio-physiological damages and cytological aberrations in cowpea varieties treated with gamma rays and sodium azide

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