A comparison of progeny from diallel crosses of diploid potato with regard to the frequencies of 2n-pollen grains

Euphytica ◽  
1995 ◽  
Vol 92 (3) ◽  
pp. 313-320
Author(s):  
Qu Dongyu ◽  
Zhu Dewei ◽  
M. S. Ramanna ◽  
E. Jacobsen
Keyword(s):  
Pollen Grains ◽  
Diploid Potato ◽  
2N Pollen ◽  
Diallel Crosses

CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

1979 ◽  
Vol 21 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Nicholi Vorsa ◽  
E. T. Bingham
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Pollen Grains ◽  
Genetic Constitution ◽  
2N Pollen ◽  
Diploid Parent ◽  
2N Gamete ◽  
Medicago Sativa L ◽  
Pollen Formation ◽  
Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

scholarly journals Morphological diversity of pollen from selected species of the genus Taraxacum, according to their ploidal level

2012 ◽  
Vol 61 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Jolanta Marciniuk ◽  
Anna Rudzińska-Langwald
Keyword(s):  
Pollen Grains ◽  
Morphological Diversity ◽  
Great Variability ◽  
2N Pollen ◽  
Regular Type ◽  
Unknown Number ◽  
Species Being ◽  
The Way

The study of the morphology of pollen concerned eight species of the genus <i>Taraxacum</i>. Seven types were chosen with a different number of chromosomes belonging to the section <i>Palustria</i>: <i>Taraxacum paucilobum</i> 2n = 3x = 24, <i>T. subdolum</i> 2n = 3x =24, <i>T. subpolonicum</i> 2n =3x = 24, <i>T. vindobonense</i> 2n = 4x = 32, <i>T. trilobifolium</i> 2n = 4x = 32, <i>T. mendax</i> 2n = 5x = 40, <i>T. portentosum</i> 2n =? and one type from the section <i>Obliqua</i> - <i>T. platyglossum</i> 2n =?. Pollen from all the examined species was observed by SEM microscopy. A distinct relation exists between the morphology of pollen and the way of reproduction. Pollen of triploidal species, being compulsory apomicts, is characterized by a great variability of the size and a high percentage of deformed pollen grains. Tetraploids, being optional apomicts, produce regular pollen with a relatively even size. The regular type of pollen in pentaploidal <i>Taraxacum mendax</i> and in species with an unknown number of chromosomes (<i>Taraxacum portentosum</i> and <i>T. platyglossum</i>) suggests that these taxa are optional apomicts.

scholarly journals Colchicine did not affect the viability of induced 2n pollen in Populus tomentosa

Silva Fennica ◽  
2019 ◽  
Vol 53 (2) ◽  
Author(s):  
Yan Liu ◽  
Yuan Zhang ◽  
Qing Zhou ◽  
Jian Wu ◽  
Pingdong Zhang
Keyword(s):  
Pollen Germination ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Populus Tomentosa ◽  
2N Pollen ◽  
Significant Difference ◽  
Diploid Pollen ◽  
Germination Experiments ◽  
Diploid Gametes

Colchicine is widely used as a mutagen to induce production of diploid gametes in plants. However, whether colchicine affects induced pollen viability remains unclear. To clarify whether colchicine affected the viability of induced pollen, we induced production of diploid pollen by colchicine, followed by pollen germination and crossing induced pollen with normal gametes to produce triploid in Carrière. The results showed that the predominant meiotic stages and the number of colchicine injections had significant effects on the occurrence rates of induced 2n pollen. When the colchicine injection was given at diakinesis, a significant decrease in the pollen production per bud was observed ( < 0.001). The morphology of the colchicine-induced 2n pollen was similar to that of the natural 2n pollen in its ectexine structure. The pollen germination experiments revealed that there was also no significant difference in germination rates between the induced diploid pollen and natural 2n pollen grains, and 68 triploids were created by crossing colchicine-induced pollen. Our findings revealed that colchicine injection could induce to produce 2n pollen and will not lead to dysfunction of induced diploid pollen.in vitroPopulus tomentosapP. tomentosa

Anther culture of a 2n pollen producing clone of Solanum phureja Juz. &Buk.

1985 ◽  
Vol 27 (5) ◽  
pp. 559-564 ◽  
Author(s):  
R. E. Veilleux ◽  
J. Booze-Daniels ◽  
E. Pehu
Keyword(s):  
Anther Culture ◽  
Polyacrylamide Gel Electrophoresis ◽  
Pollen Grains ◽  
Unreduced Gametes ◽  
Solanum Phureja ◽  
2N Pollen ◽  
Regenerated Plants ◽  
Series Of Experiments ◽  
Pollen Formation ◽  
First And Second Generation

In a series of experiments, a total of 95 plants were regenerated from culture of 1416 anthers of a single genotype (PP5) of Solanum phureja that expressed a variable frequency of 2n pollen by the genetic equivalent of first division restitution. The regenerated plants included 29 monoploids (2n = x = 12), 58 diploids (2n = 2x = 24) and 8 tetraploids (2n = 4x = 48). Monoploids carrying the potential for 2n pollen formation are central to the development of a breeding scheme to construct highly heterozygous diplandroids. Segregation of tuber flesh color and tuber protein bands revealed by polyacrylamide gel electrophoresis in first and second generation anther-derived diploid plants provided evidence for both embryogenesis of 2n pollen as well as doubling of monoploid genomes as sources of anther-derived diploids. Because of variation for the same genetic markers in anther-derived tetraploids, sources other than embryogenesis of doubly restituted (4n) pollen grains were implied. An enhanced response to anther culture was noted in some anther-derived dihaploids.Key words: unreduced gametes, potato, anther culture, diplandroid, monoploid.

INTER-COMPATIBILITY AND PERFORMANCE OF DIPLOID AND DERIVED TETRAPLOID RAPE (BRASSICA CAMPESTRIS L.)

1962 ◽  
Vol 42 (4) ◽  
pp. 672-680 ◽  
Author(s):  
R. K. Downey ◽  
J. M. Armstrong
Keyword(s):  
Seed Oil ◽  
Brassica Campestris ◽  
Early Stage ◽  
Pollen Grains ◽  
2N Pollen ◽  
Seed Oil Content ◽  
Ploidy Levels ◽  
Good Penetration ◽  
Selection For ◽  
And Performance

Normal diploid and derived tetraploid strains of Brassica campestris were grown in alternate 6-row plots at two locations. Rows of tetraploid rape, spaced 18 inches from diploid rows, were distinctly reduced in yield of seed, oil content and seeds per pod, whereas the seed yield of the diploid was not affected by the proximity of the tetraploid. The yield of the tetraploid increased as the distance from the diploid plots increased.Pollen germination studies and controlled crosses were made within and between ploidy levels. Seven and one-half hours after pollination of 2n and 4n stigmas, n pollen had germinated and made good penetration into stylar tissue whereas pollen tubes were just emerging from 2n pollen grains. It was concluded that pollen from diploid plants had a competitive advantage over pollen from tetraploid plants.No evidence of mature triploid seeds was found on tetraploid plants exposed to n pollen or on diploid plants exposed to 2n pollen. It is suggested that if triploid embryos were formed they aborted at an early stage in development.Comparative yield of seed and oil at 13 locations showed that the derived tetraploid strains yielded less than diploid varieties. This was true despite six to eight generations of selection for seed and oil yield, following synthesis of the tetraploid, and although the strains were isolated in groups according to level of ploidy.

scholarly journals Separation of 2n Potato Pollen from a Heterogeneous Pollen Mixture by Velocity Sedimentation

HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 342-344 ◽  
Author(s):  
Charles J. Simon ◽  
John C. Sanford
Keyword(s):  
Pollen Grains ◽  
Breeding Program ◽  
Velocity Sedimentation ◽  
2N Pollen ◽  
Sexual Polyploidization ◽  
Heterogeneous Mixture ◽  
Ploidy Levels ◽  
Normal Pollen ◽  
Small Pollen ◽  
Pollen Mixture

A method is described for separating large and small pollen effectively from a heterogeneous mixture. This method potentially is applicable to separation of pollen grains of different ploidy levels, since “unreduced” 2n pollen is larger than normal pollen (n); it might then be used to increase the efficiency of a breeding program employing sexual polyploidization and to diminish crossing inefficiencies in interploid crosses.

scholarly journals Impact of cytomixis on the microspogenesis and formation of unreduced pollen grains in monocots

2017 ◽  
Vol 20 ◽  
pp. 26-30
Author(s):  
E. A. Kravets ◽  
S. H. Plohovskaya ◽  
I. I. Horyunova ◽  
A. I. Emets ◽  
Ya. B. Blume
Keyword(s):  
Meiotic Division ◽  
Functional Role ◽  
Fluorescent Microscopy ◽  
Pollen Grains ◽  
Allium Fistulosum ◽  
2N Pollen ◽  
Significant Progress ◽  
Unreduced Pollen ◽  
Meiotic Chromosomes ◽  
Allium Cepa L

Aim. Despite significant progress in the investigation of cytomixis its functional role and effect on the course of meiosis as well as mechanisms of 2n pollen grains formation is still not completely clear. We have studied the destination of cytomictic chromatin as well the mechanisms of unreduced microspores formation in species of monocots with spontaneous cytomixis. Methods. Light and fluorescent microscopy. Results. The cytomictic chromatin forms additional meiotic chromosomes in the recipient microsporocytes. Many of these meiotic chromosomes undergo rearrangement and fragmentation but retain their bivalent organization. Conclusions. Cytogenetic anomalies of microsporogenesis caused by activation of cytomixis in prophase may reflect meiosis stabilization mechanisms by assimilation and adaptation or diminution and reutilization of the introduced DNA. The main mechanism of polyploidization of microsporocytes and pollen grains in studied monocots is the restitution of the first meiotic division via the formation of a meta-anaphase 1 block.Keywords: cytomixis, microsporogenesis, additional (recipient) chromosomes, meta-anaphase 1 block, Lilium croceum Chaix., Allium cepa L., Allium fistulosum L.

scholarly journals UNREDUCED POLLEN: PROPOSED MECHANISM OF POLYPLOIDIZATION OF SWEETPOTATO (IPOMOEA BATATAS)

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 611a-611
Author(s):  
Janice R. Bohac ◽  
Alfred Jones ◽  
Daniel F. Austin
Keyword(s):  
Ploidy Level ◽  
Ipomoea Batatas ◽  
Indirect Evidence ◽  
Pollen Grains ◽  
2N Pollen ◽  
Breeding Programs ◽  
First Report ◽  
New Findings ◽  
Low Levels

Previous work in this laboratory identified high levels of unreduced (2n) pollen in the tetraploid (4×) Ipomoea spp. Acc. 81.2. This work provided indirect evidence that 2n pollen was involved in the evolution of the 6x ploidy level of the cultivated sweetpotato (I. batatas). To further study the role of 2n pollen in sweetpotato evolution, we examined plants of Acc. 81.2. plants of five sweetpotato cultivars, and 100 randomly selected heterozygous sweetpotato seedlings. The 4× Acc. 81.2 was determined to be I. batatas. High levels of large 2n pollen were confirmed in Acc. 81.2, and low levels of 2n pollen were observed in `Sulfur' and in 16% of the sweetpotato seedlings. Presence of monad, dyad, and triad sporads confirmed that the large 2n pollen grains were the result of nonreduction in the sporad stage. These new findings are direct evidence that 2n pollen was involved in the evolution of the 6× ploidy level of sweetpotato. This is the first report of a 4× accession classified as I. batatas; it is also the first report of 2n pollen in 6× I. batatas The widespread presence of 2n pollen in sweetpotato suggests that the trait can be used to advantage in breeding programs to introgress genes from wild 4× Ipomoea spp. into cultivated 6× sweetpotato without adverse effects on genetic stability or fertility.

scholarly journals Distribution of Microtubular Cytoskeletons and Organelle Nucleoids During Microsporogenesis in a 2n Pollen Producer of Hybrid Populus

2009 ◽  
Vol 58 (1-6) ◽  
pp. 220-226 ◽  
Author(s):  
J. Wang ◽  
X. Y. Kang
Keyword(s):  
Indirect Immunofluorescence ◽  
Pollen Grains ◽  
Pollen Production ◽  
2N Pollen ◽  
Meiotic Abnormalities ◽  
Chromosome Behavior ◽  
Dapi Staining ◽  
Populus Simonii ◽  
Parallel Spindles ◽  
The Relationship

Abstract The distribution of microtubular cytoskeletons and organelle nucleoids during microsporogenesis in Populus simonii Carr. x P. nigra L. ‘Tongliao’ was studied by indirect immunofluorescence and 4’,6-diamidino-2- phenylindole (DAPI) staining. Our purpose was to reveal the relationship between changes in microtubule and chromosome behavior and cytokinesis and to explain the mechanism of 2n pollen production. We observed stable frequencies of 2n pollen production, ranging from 1.56% to 2.29%, between 2006 and 2008. Moreover, conjoined pollen grains were also observed. Meiotic abnormalities, including univalents, lagging chromosomes and micronuclei, were observed during microsporogenesis. Triads and dyads were also detected in meiotic products. Parallel spindles in metaphase II were unable to fuse, owing to the existence of an organelle band. Regularly, in telophase II, primary phragmoplasts were organized between sister nuclei, and secondary phragmoplasts formed between non-sister nuclei. Cell plates were initiated by centrifugal expansion of phragmoplasts and cytoplasmic infurrowing started at the junctions between the microsporocyte wall and the expanded phragmoplasts. However, a secondary phragmoplast was absent in some microsporocytes. These observations suggest that the occurrence of 2n pollen may result from the partial failure of cytokinesis caused by the absence of secondary phragmoplasts in this hybrid.

scholarly journals Use of 2n Giant Pollen to Produce Nonaploid Japanese Persimmon

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 441B-441
Author(s):  
R. Tao ◽  
T. Ohkuma ◽  
M. Tamura ◽  
A. Sugiura
Keyword(s):  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Pollen Grains ◽  
2N Pollen ◽  
Japanese Persimmon ◽  
Normal Pollen ◽  
Nylon Mesh ◽  
Flow Cytometric ◽  
Pollen Diameter

Distribution of pollen diameter of Japanese persimmon cv. Zenjimaru (2n = 6x, × = 15) was determined using pollen grains hydrated with CPW solution supplemented with 0.9 M mannitol. Mean diameter of giant pollen grains (65 μm) was 1.3 times longer than that of normal pollen grains (50 μm). The occurrence of giant pollen was estimated to be about 5% of the pollen population. The hydrated giant pollen grains could be sorted out from normal pollen grains by filtering through a layer of nylon mesh (62 μm). Flow cytometric analysis of nuclear DNA content confirmed that giant pollen was unreduced 2n pollen. 2n giant pollen grains were pollinated to cn. Jiro (2n = 6x) callie and plantlets could be obtained from immature embyros excised from seeds 70 days after pollination.

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