Chromosome numerical mosaicism in pearl millet (Pennisetum americanum (L.) Leeke)

1986 ◽  
Vol 28 (2) ◽  
pp. 203-206 ◽  
Author(s):  
Panuganti N. Rao ◽  
A. Nirmala

In pearl millet (Pennisetum americanum (L.) Leeke, 2n = 14), a wide range of intraplant chromosome numerical variation occurring in pollen mother cells at meiosis within the same anther, floret, or spike was found in eight plants. The types of mosaicism encountered were haploid–diploid, diploid–tetraploid, haploid–diploid–aneuploid, and diploid–tetraploid–aneuploid–teloaneuploid. Their probable mode of origin is discussed.Key words: Pennisetum, chromosomal numerical mosaicism.

1990 ◽  
Vol 115 (3) ◽  
pp. 512-516 ◽  
Author(s):  
Alfred Jones

Nonreduction of pollen mother ceils was observed in a wild tetraploid morning-g&y related to the sweetpotato (Ipomoea batatas L. Lam.). Techniques for identifying and determining the frequency of expression of the trait are straightforward. Previous strategies for transfer of germplasm from tetraploid (2n = 4x = 60) species to the hexaploid (2n = 6x = 90) sweetpotato involved crosses with diploids (2n = 2x = 30) to obtain triploids that then were doubled to 6x. Nonreduction of pollen mother cells probably represents the natural mechanism for raising 4x to 6x since pollination of 2x ovules with unreduced pollen (4x) should give rise to 6x progeny without need for somatic doubling. Plants carrying this trait should be useful as bridging types for introgressing genes from wild 4x species into sweetpotato. A wide range in nonreduction (up to, 74%) was recovered In progeny of controlled crosses among selected plants, but data were not sufficient to estimate gene action.


1984 ◽  
Vol 26 (5) ◽  
pp. 506-510 ◽  
Author(s):  
P. S. R. L. Narasinga Rao ◽  
J. Sybenga

Robertsonian trivalents, trisomic trivalents, and tetrasomic ring quadrivalants showed linear or indifferent orientation frequencies at late metaphase I of 1/3. This fits a model assuming sequential centromere activation in the multivalent with random order of activation and sufficiently long interval to permit stable coorientation of any two early centromeres before the following centromere is activated. A late centromere trapped between two coorienting early ones is prevented from orientation. Reorientation in pearl millet, when it occurs, is late in these configurations. Chain quadrivalents have less linear but more indifferent orientations than the expected 1/6 and 1/3, respectively. Possible reasons for this are given. For rye the situation is very different: linear orientation of Robertsonian trivalents is practically absent, presumably owing to insufficiently long intervals between centromere activations, and to early reorientation. A reduction in interval length between centromere activations is assumed to accompany the stabilization of autotretraploids.Key words: pearl millet, trivalents, quadrivalents, centromere activation, chromosome orientation.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Ekram Abdel Haliem ◽  
Hanan Abdullah ◽  
Asma A. AL-Huqail

In recent years, there has been a great deal of attention toward free radicals, reactive oxygen species (ROS) generated by exposure of crop plant cells to physical radiations. Henceforth, the current study was planned to compare oxidative stress and mutagenic potential of different irradiation doses of fast neutron (FN) and UV-B on meiotic-pollen mother cells (PMCs), pollen grains (PGs) and seeds yielded from irradiated faba beans seedlings. On the cytogenetic level, each irradiation type had special interference with DNA of PMC and exhibited wide range of mutagenic action on the frequency and type of chromosomal anomalies, fertility of PGs and seed yield productivity based on the irradiation exposure dose and radiation sensitivity of faba bean plants compared with un-irradiated ones. On the molecular level, SDS-PAGE and RPAD-PCR analyses of seeds yielded from irradiated seedlings exhibited distinctive polymorphisms based on size, intensity, appearance, and disappearance of polypeptides bands compared with un-irradiated ones. The total values of protein and DNA polymorphisms reached 88% and 90.80% respectively. The neutron fluency (2.3 × 106 n/cm2) and UV-B dose for 1 hr were recorded as bio-positive effects. The present study proved that genetic variations revealed by cytogenetic test could be supported by gene expression (alterations in RAPD and protein profiles).


Caryologia ◽  
2003 ◽  
Vol 56 (3) ◽  
pp. 275-279 ◽  
Author(s):  
Wei Li ◽  
Jun Yang ◽  
You-Fu Pan ◽  
Guang-Qin Guo ◽  
Guo-Chang Zheng

PROTOPLASMA ◽  
2011 ◽  
Vol 248 (4) ◽  
pp. 717-724 ◽  
Author(s):  
Sergey R. Mursalimov ◽  
Elena V. Deineko

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Batia Pazy ◽  
Uzi Plitmann

Idiosyncratic chromosome behaviour during meiosis was found in pollen mother cells of Cuscuta babylonica Choisy, a thread-like holoparasitic herb. Its main features are among the following: (i) telomeric association between homologues through most stages of the process, which leads to persisting chromatid bivalents (= "demibivalents"); (ii) uncommon chromosome segregation in first and second anaphase; and (iii) prolonged intensified heterochromatinization. Although "regular" in its own way, this process leads to the formation of unviable products. Its further investigation might contribute to our understanding of the role of the spindle and chromosome movement in the ordinary process of meiosis. Key words: meiosis (abnormal), persisting demibivalents, Cuscuta babylonica.


1945 ◽  
Vol 23c (4) ◽  
pp. 131-143 ◽  
Author(s):  
M. W. Bannan

Seedlings at different stages of development were treated with colchicine. Successive selections on the aspect of the seedlings soon after treatment, on size of the guard cells at the time of repotting, and finally, after overwintering, on counts of the chromosomes in the pollen mother cells yielded a few hundred plants with tetraploid crowns. These plants bore fewer, broader leaves and fewer, bigger inflorescences with larger achenes than did selected large-celled diploids given the same treatment, but in general the plants were no bigger. A few of the tetraploids were self-fertile (if not apomictic) early in the spring, but later all tested plants proved self-sterile.


1976 ◽  
Vol 18 (2) ◽  
pp. 281-286 ◽  
Author(s):  
C. C. Chinnappa ◽  
J. C. Semple

In two diploid specimens of Haworthia subfasciata (2n = 14) several kinds of chromatid and subchromatid aberrations occurred. In some pollen mother cells E-type and U-type bridges were present. In other cells bridges and fragments were formed due to asymmetrical reunion of nonsister chromatids following breakage. A translocation involving the satellites of two L pair chromosomes was observed in one plant.


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