Second meiotic division restitution (SDR) 2n pollen formation in diploid and hexaploid species of Asparagus

1994 ◽  
Vol 41 (1) ◽  
pp. 1-7 ◽  
Author(s):  
E. L. Camadro
Keyword(s):  
Meiotic Division ◽  
2N Pollen ◽  
Hexaploid Species ◽  
Pollen Formation

THREE MECHANISMS OF 2n POLLEN FORMATION IN DIPLOID POTATOES

1975 ◽  
Vol 17 (2) ◽  
pp. 217-225 ◽  
Author(s):  
D. W. S. Mok ◽  
S. J. Peloquin
Keyword(s):  
Meiotic Division ◽  
Genetic Data ◽  
The Other ◽  
Cleavage Furrow ◽  
2N Pollen ◽  
Parallel Spindles ◽  
Solatium Tuberosum ◽  
Pollen Formation ◽  
Group Tuberosum

Three mechanisms of 2n pollen formation observed in diploid hybrids between Solatium tuberosum Group Phureja (2x) and haploids of S. tuberosum Group Tuberosum (4x) are termed parallel spindles (ps), premature cytokinesis 1 (pc 1) and premature cytokinesis 2 (pc 2). A II spindles are parallel to each other in many cells of clones producing 2n pollen by ps. A single cleavage furrow follows and forms a dyad which generates two 2n microspores. The other two mechanisms, pc 1 and pc 2, produce 2n pollen by omission of the second meiotic division. Premature cytokinesis 1 (pc 1) involves asynchronized movement of bivalents to and from the M I plate and falling apart of chromatids at T I. A cleavage furrow follows the first meiotic division, no second division occurs and products of meiosis are dyads. Premature cytokinesis 2 (pc 2) exhibits no abnormalities at the first meiotic division. However, cytokinesis occurs prematurely at P II, no second division occurs, and only dyads are formed. Genetic data suggested that these three mechanisms may be controlled by single loci, and are inherited independently as simple recessives.

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.

Cytological mechanisms of 2n pollen formation in the wild potato Solanum okadae and pollen-pistil relations with the cultivated potato, Solanum tuberosum

2007 ◽  
Vol 55 (3) ◽  
pp. 471-477 ◽  
Author(s):  
Elsa Lucila Camadro ◽  
Sandra Karina Saffarano ◽  
Juan Carlos Espinillo ◽  
Mateo Castro ◽  
Phillip W. Simon
Keyword(s):  
Solanum Tuberosum ◽  
Wild Potato ◽  
2N Pollen ◽  
Cultivated Potato ◽  
In The Wild ◽  
Pollen Formation

Cytological mechanism of 2n pollen formation and unilateral sexual polyploidization in Lolium

Euphytica ◽  
1989 ◽  
Vol 43 (1-2) ◽  
pp. 1-6 ◽  
Author(s):  
C. A. Sala ◽  
E. L. Camadro ◽  
M. T. Salaberry ◽  
A. O. Mendiburu
Keyword(s):  
2N Pollen ◽  
Sexual Polyploidization ◽  
Unilateral Sexual Polyploidization ◽  
Pollen Formation ◽  
Cytological Mechanism

Meiotic aberrations during 2n pollen formation in Begonia

Heredity ◽  
2009 ◽  
Vol 104 (2) ◽  
pp. 215-223 ◽  
Author(s):  
A Dewitte ◽  
T Eeckhaut ◽  
J Van Huylenbroeck ◽  
E Van Bockstaele
Keyword(s):  
2N Pollen ◽  
Pollen Formation ◽  
Meiotic Aberrations

2n pollen formation via parallel spindles in the potato cultivar sebago

1980 ◽  
Vol 57 (9) ◽  
pp. 449-455 ◽  
Author(s):  
E. W. Souter ◽  
J. C. Dawe ◽  
S. J. Peloquin
Keyword(s):  
Potato Cultivar ◽  
2N Pollen ◽  
Parallel Spindles ◽  
Pollen Formation

scholarly journals Complete asynapsis resulting in 2n pollen formation in Paspalum jesuiticum Parodi (Poaceae)

2014 ◽  
Vol 13 (1) ◽  
pp. 255-261 ◽  
Author(s):  
R.A. Bernardo Filho ◽  
A.C.C. Santos ◽  
F.H.D. Souza ◽  
J.F.M. Valls ◽  
M.S. Pagliarini
Keyword(s):  
2N Pollen ◽  
Pollen Formation
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