Inheritance and microsporogenesis of a synaptic mutant (sy-2) from Solanum commersonii Dun.

1986 ◽  
Vol 28 (4) ◽  
pp. 520-524 ◽  
Author(s):  
S. A. Johnston ◽  
R. W. Ruhde ◽  
M. K. Ehlenfeldt ◽  
R. E. Hanneman Jr.
Keyword(s):  
Chromosome Segregation ◽  
2N Gametes ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Crossing Over ◽  
2N Pollen ◽  
Solanum Commersonii ◽  
Stainable Pollen ◽  
Tetrad Stage ◽  
Meiotic Mutants

A mutant has been found in diploid Solanum commersonii (2n = 2x = 24) in which no bivalents are formed during microsporogenesis. This trait, a simply inherited recessive, has been designated sy-2. It conditions high levels of pollen sterility through random chromosome segregation at anaphase I. Only the nucleolar-associated chromosomes appear to segregate non-randomly, possibly due to the fusion of the nucleoli as cells near diakinesis. Branched spindle configurations result in multipolar telophase I arrangements, yielding from one to seven pollen grains at the tetrad stage. Most of the stainable pollen produced appears to be 2n. The 2n pollen formed by this mechanism should bear the exact genotype of the parent, since no crossing-over occurs.Key words: Solanum, potato, 2n gametes, mutants (meiotic), mutants (synaptic).

2n gametes in Solanum commersonii and cytological mechanisms of triplandroid formation in triploid hybrids of Solanum commersonii × Solanum gourlayi

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 864-869 ◽  
Author(s):  
R. W. Masuelli ◽  
E. L. Camadro ◽  
A. O. Mendiburu
Keyword(s):  
2N Gametes ◽  
Pollen Grains ◽  
Solanum Commersonii ◽  
Stainable Pollen ◽  
Large Size ◽  
Common Potato ◽  
Aneuploid Chromosome ◽  
The Common ◽  
Bridge Species ◽  
Solanum Gourlayi

Solanum commersonii Dun. (cmm) is a diploid wild species of potential value for potato breeding. Ploidy level manipulations are necessary to cross this species with the common potato. This could be achieved by the use of "bridge" species and sexual polyploidization in which 2n gametes are involved. Eight introductions of cmm were screened for production of (i) diplandroids, through cytological observations confirmed by controlled 4x Solanum acaule Bitt. (acl) × 2x cmm crosses, and (ii) diplogynoids, by controlled 2x cmm × 2x Solanum gourlayi Haw. (grl) crosses. Eleven plants produced 1–3% large size pollen and one plant produced more than 3% of this type of pollen. Twelve triploid and seven tetraploid hybrids were obtained when these plants were used in crosses with acl. On the other hand, 75 triploid hybrids were obtained from the second type of cross. The average pollen stainability in the diplogynoid triploid cmm × grl hybrids was 18.9%, with a range of 2–34.4%. Forty-four to 54.6% of meiocytes with parallel spindles in metaphase II and anaphase II were observed in microsporogenesis of these hybrids. For each clone, the frequency of triplandroids predicted according to the frequency of meiocytes with parallel, fused and tripolar spindles in anaphase II were 52.3, 36.6, and 45.2%, respectively. These values were highly superior to the frequency of triplandroids predicted according to the number of dyads and triads observed, 8.8, 0.7, and 3.9%, respectively. However, triplandroid frequencies predicted according to the frequencies of fused and tripolar spindles agree with the triplandroid frequencies observed. The frequencies of stainable pollen grains are not completely accounted for by the formation of fused and tripolar spindles. In view of the variability encountered in size, it is assumed that a high proportion of gametophytes with aneuploid chromosome numbers are also stainable. A hypothesis is put forward regarding the possible genetic control of triplandroid formation in the diplogynous triploid hybrids analyzed.Key words: 2n gametes, triploid hybrids, spindle orientation, Solanum commersonii Dun.

scholarly journals High Temperature-induced Spindle Destabilization Results in Aborted Pollen Production in Populus

2021 ◽  
Author(s):  
Zhiqun Li ◽  
Yifan Zhao ◽  
Xuetong Cheng ◽  
Bo Kong ◽  
Yaru Sang ◽  
...  
Keyword(s):  
High Temperature ◽  
Chromosome Segregation ◽  
2N Gametes ◽  
Male Flower ◽  
Pollen Grains ◽  
Pollen Abortion ◽  
Duration Of Treatment ◽  
Male Gametes ◽  
Microtubular Cytoskeleton ◽  
Spindle Microtubules

Abstract High temperature can induce the production of 2n gametes and aborted pollen during microsporogenesis in Populus canescens. However, the mechanism by which high temperature induces pollen abortion remains unknown. Here, pollen abortion was induced by exposing male flower buds of P. canescens to 38 and 41 °C; pollen morphology, meiotic abnormalities, defects of the meiotic microtubular cytoskeleton, and tapetum development were characterized, and expression analysis of the Actin gene was conducted. We found that the dominant meiotic stage, temperature, and duration of treatment significantly affected the percentage of high temperature-induced aborted pollen. Damaged spindle microtubules and depolymerized microtubular cytoskeletons were observed, which resulted in many lagging chromosomes at anaphase Ⅰ and Ⅱ, as well as aneuploid male gametes and micronuclei, generating aborted pollen grains. Tapetum disintegration was also delayed. However, the anther dehisced normally, and some viable pollen grains were released, suggesting that the delayed degradation of the tapetum was not responsible for pollen abortion. A significant reduction in PtActin gene expression was detected in treated cells, indicating that spindle actin was disrupted. The spindle actin appeared to protect cells against chromosome segregation errors during meiosis.

scholarly journals High Pollen Sterility and 2n Pollen Grains in an Asynaptic 4x Cytotype (2n=48) of Solanum nigrum L.

CYTOLOGIA ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. 333-342 ◽  
Author(s):  
Vijay Kumar Singhal ◽  
Maninder Kaur ◽  
Himshikha Puneet Kumar ◽  
Raghbir Chand Gupta
Keyword(s):  
Pollen Grains ◽  
Pollen Sterility ◽  
Solanum Nigrum ◽  
2N Pollen ◽  
High Pollen ◽  
Solanum Nigrum L

Production of total and stainable pollen grains inOlea europaeaL

Grana ◽  
2007 ◽  
Vol 46 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Giuseppe Ferrara ◽  
Salvatore Camposeo ◽  
Marino Palasciano ◽  
Angelo Godini
Keyword(s):  
Pollen Grains ◽  
Stainable Pollen

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 Temporal Distinction between Male and Female Floral Organ Development in Nicotiana tabacum cv. Xanthi (Solanaceae)

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 127
Author(s):  
Hongli Chang ◽  
Fengjie Sun
Keyword(s):  
Nicotiana Tabacum ◽  
Molecular Mechanisms ◽  
Pollen Grains ◽  
Floral Organ ◽  
Evolutionary Mechanisms ◽  
Tetrad Stage ◽  
Flower Primordia ◽  
Future Studies ◽  
Carpel Development ◽  
Solid Foundation

Early floral developmental investigations provide crucial evidence for phylogenetic and molecular studies of plants. The developmental and evolutionary mechanisms underlying the variations in floral organs are critical for a thorough understanding of the diversification of flowers. Ontogenetic comparisons between anthers and pistil within single flowers were characterized over time in Nicotiana tabacum cv. Xanthi. The ages of 42 tobacco flower or flower primordia were estimated using corolla growth analysis. Results showed that the protodermal layer in carpel primordia contributes to carpel development by both anticlinal and periclinal divisions. Periclinal divisions in the hypodermal layer of the placenta were observed around 4.8 ± 1.3 days after the formation of early carpel primordia (ECP) and ovule initiation occurred 10.0 ± 0.5 days after ECP. Meiosis in anthers and ovules began about 8.9 ± 1.1 days and 14.4 ± 1.3 days after ECP, respectively. Results showed an evident temporal distinction between megasporogenesis and microsporogenesis. Flower ages spanned a 17-day interval, starting with flower primordia containing the ECP and anther primordia to the tetrad stage of meiosis in megasporocytes and the bicellular stage in pollen grains. These results establish a solid foundation for future studies in order to identify the developmental and molecular mechanisms responsible for the mating system in tobacco.

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

scholarly journals Pollen and Spikelet Analysis in F1 Rice Hybrids and their Parents

2014 ◽  
Vol 8 ◽  
pp. 120-126 ◽  
Author(s):  
Bal K. Joshi ◽  
Laxmi P. Subedi ◽  
Santa B. Gurung ◽  
Ram C. Sharma
Keyword(s):  
Pollen Fertility ◽  
Practical Importance ◽  
Pollen Grains ◽  
Gene Interaction ◽  
Pollen Sterility ◽  
Spikelet Fertility ◽  
High Fertility ◽  
Male Sterile ◽  
Pollen Abortion ◽  
Spikelet Sterility

Pollen analysis can be used to discriminate between different species, identify possible  interspecies hybrids, identify restorer and maintainer lines, useful to study genetics of  restorer gene, interaction between chromosome and cytoplasm and relationship between  parents. Pollen abortion system of male sterility is an important tool in hybrid rice  production and spikelet is the major yield components. Nine improved cultivars, six  landraces and three wild aborted cytoplasmic-genetic male sterile (CMS) lines were used to  analyze pollen and spikelet in F1 rice hybrids and their parents. The frequency of pollen  categories and its relationship to spikelet fertility were investigated. Pollen sterility of the  F1s was determined by staining pollen grains in 1% potassium iodide-iodine (I-KI) solution.  Spikelet fertility was determined by counting the total number of seed set in proportion to  the total number of spikelets. Correlation and regression coefficients for some traits were  computed. In hybrids, pollen fertility ranged from 0.5 to 82% and spikelet fertility from 0 to  87%. Pollen fertility varied from 28 to 97%, while spikelet fertility from 73 to 91% in pollen  parents. The highest and the lowest percentages of pollen fertility were found in Chaite-6  and Chiunde cultivars respectively. Spikelet fertility percentage varied widely among  hybrids and many hybrids had lower spikelet fertility percentage than their parents.  Therefore, it is of practical importance to understand the causes of high spikelet sterility in  hybrids for possible increase in spikelet fertility. Highly significant positive correlation was  found between stained round fertile (SRF) pollen and spikelet fertility. The positive value of  correlation and regression coefficient on SRF and spikelet fertility were found between F1  and mid parent, and F1 and male parent. High fertility of cross may be due to the presence of  a wide compatibility gene or restorer genes in the cultivar. Lower pollen and spikelet  fertility of the crosses was attributed to effect of the genetic background of the tester parent. Nepal Agric. Res. J. Vol. 8, 2007, pp. 120-126 DOI: http://dx.doi.org/10.3126/narj.v8i0.11605  

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