Cytogenetic variation in rye regenerated plants and their progeny

Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 428-430 ◽  
Author(s):  
R. Linacero ◽  
A. M. Vazquez
Keyword(s):  
Chromosome Number ◽  
Somaclonal Variation ◽  
Secale Cereale ◽  
Immature Embryo ◽  
Meiotic Abnormalities ◽  
Regenerated Plants

Regenerated plants obtained from immature embryo-derived calluses of four cultivars of rye, as well as their progeny, were cytologically analyzed. Chromosome number modified plants were found among the regenerants. The progeny of apparently normal diploid regenerated plants was tested and in some cases chromosomally abnormal plants appeared. Equally, meiotic abnormalities were observed in some of the regenerated plants and their progenies. The cytological variations observed were inheritable and in some cases both types of abnormalities could be related. The nature of the variations is discussed.Key words: Secale cereale, somaclonal variation, nondiploid plants, meiotic abnormalities.

Somaclonal variation from cultured immature embryos of sister lines of rye differing in heterochromatic content

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 177-183 ◽  
Author(s):  
P. J. Bebeli ◽  
A. Karp ◽  
P. J. Kalts1kes
Keyword(s):  
Somaclonal Variation ◽  
Storage Proteins ◽  
Immature Embryo ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Immature Embryos ◽  
Chromosome Variation ◽  
Regenerated Plants ◽  
Immature Embryo Culture ◽  
Telomeric Heterochromatin

Somaclonal variation occurred among rye plants regenerated from cultured immature embryos of five sister lines that differed in their content of telomeric heterochromatin. Variation was observed in morphology, chromosome number, and secalin seed storage proteins. Morphological variation was present in 9.7% of the regenerants and included albinism and variegation, which appeared in different frequencies among the lines. Chromosome variation occurred in 15.8% of the regenerants and included translocations, tetraploidy, and trisomy in addition to meiotic disturbances such as centromere misbehaviour and asyndesis. Some of the regenerated plants were mosaic for the structural and numerical chromosome aberrations. The nature of the chromosome variation also differed among the lines. A single variant in the 40K γ-secalins was detected. The occurrence of variation is discussed in relation to differences in morphogenetic response of the rye lines and to the genotypic component of instability in culture.Key words: somaclonal variation, immature embryo culture, rye heterochromatin, chromosome variation, secalins.

Genetic analysis of chlorophyll-deficient somaclonal variants in rye

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 981-984 ◽  
Author(s):  
R. Linacero ◽  
A. M. Vazquez
Keyword(s):  
Genetic Analysis ◽  
Transposable Elements ◽  
Secale Cereale ◽  
Immature Embryo ◽  
The Other ◽  
Albino Plants ◽  
Regenerated Plants ◽  
In Vitro Activation ◽  
Chlorophyll Deficiencies

Albino plants have been observed among regenerated plants from immature embryo calluses in four cultivars of rye. The frequency of albino plants was very similar between the plants regenerated from embryogenic (8.78%) or organogenic (12.06%) cultures. However, these frequencies varied widely between cultivars (from 0 to 23.46%). On the other hand, 12% of the green regenerated plants segregated in their progeny plants with chlorophyll deficiencies, and most of these mutations segregated as we can expect a Mendelian trait to do. The behaviour of the regenerated plants from cv. Ailes was particularly interesting, because the appearance of a particular phenotype could be related to the in vitro activation of a transposable element.Key words: Secale cereale, regeneration, somaclonal variation, albino plants, transposable elements.

Cytogenetic studies of leafy spurge, Euphorbia esula, and its allies (Euphorbiaceae)

1988 ◽  
Vol 66 (11) ◽  
pp. 2247-2257 ◽  
Author(s):  
A. E. Stahevitch ◽  
C. W. Crompton ◽  
W. A. Wojtas
Keyword(s):  
Seed Germination ◽  
Chromosome Number ◽  
Natural Populations ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Meiotic Abnormalities ◽  
Stability Studies ◽  
Polymorphic Species ◽  
Cytogenetic Studies ◽  
Euphorbia Cyparissias

Cytological and cytogenetic studies were carried out on populations of leafy spurge (Euphorbia esula L. s.l.) and its allies primarily from North America but also from Europe. Chromosome numbers were determined for 126 samples of E. esula, 11 of E. cyparissias L., 1 of the hybrid (E. ×pseudoesula Schur) between these two species, and 1 of E. agraria Bieb. All plants of E. esula were hexaploid. Of the total, 125 leafy spurge accessions had a chromosome number of n = 30; 1 of n = 25++. Very few meiotic abnormalities were observed. Euphorbia cyparissias was primarily tetraploid (n = 20), although occasional diploids (n = 10) were encountered. Tetraploids were fertile; diploids were sterile. The hybrid between the two foregoing species had a chromosome number of n = 25, indicating that the E. cyparissias parent was a tetraploid; meiosis in the hybrid was abnormal. Euphorbia agraria was found to have a gametic number of n = 20, which is the first chromosome number determination for this species; meiosis was normal. Artificial crosses were made successfully between 31 accessions of leafy spurge. Seed germination of the F1 progeny slightly exceeded that reported for natural populations, and meiosis was normal. Pollen stability studies were carried out on herbarium material. Stainability was 100% for most of the samples studied. Extensive pollen size polymorphism was found. It is suggested that this phenomenon supports the hypothesis that E. esula is of allopolyploid origin. No cytological or cytogenetic basis was found for considering the leafy spurge accessions examined in this study as other than as a single, albeit somewhat polymorphic, species.

Meiotic chromosome behaviour in Cenchrus ciliaris

Bothalia ◽  
1998 ◽  
Vol 28 (1) ◽  
pp. 83-90 ◽  
Author(s):  
N. C. Visser ◽  
J. J. Spies
Keyword(s):  
Chromosome Number ◽  
Meiotic Chromosome ◽  
Basic Chromosome Number ◽  
Chromosome Behaviour ◽  
Meiotic Abnormalities ◽  
Single Specimen ◽  
Cenchrus Ciliaris ◽  
Basic Chromosome ◽  
Single Genome ◽  
Meiotic Irregularities

A basic chromosome number of x = 9 has been confirmed for Cenchrus ciliaris L. Polyploidy is common and levels vary from tetraploid to hexaploid. Aneuploidv is reported for a single specimen, where two chromosomes of a single genome were lost. Various meiotic irregularities were observed. The highest incidence of meiotic abnormalities was observed in the pentaploid specimens. This was attributed to their uneven polyploid level All specimens varied from segmental alloploid to alloploid.

Paucity of somaclonal variation from immature embryo culture of barley

1989 ◽  
Vol 40 (6) ◽  
pp. 1155 ◽  
Author(s):  
DJ Luckett ◽  
D Rose ◽  
E Knights
Keyword(s):  
Tissue Culture ◽  
Somaclonal Variation ◽  
Embryo Culture ◽  
Field Trial ◽  
Immature Embryo ◽  
Immature Embryos ◽  
Golden Promise ◽  
Immature Embryo Culture ◽  
Tissue Origin ◽  
Regenerant Plants

Intact immature embryos of barley (cv. Golden Promise) and component tissues (the scutellum and embryonic axis) were cultured to produce callus. Regenerant plants were obtained from this callus and SC2 families raised. These families were examined in a field trial to search for somaclonal variation. No obvious variants were found confirming our previous unpublished results. The lack of somaclonal variation generated by barley tissue culture (which is in contrast to other species) was not a result of the tissue origin of the regeneration event.

Cytogenetic abnormalities of cotton somaclones from callus cultures

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 762-770 ◽  
Author(s):  
David M. Stelly ◽  
D. W. Altman ◽  
R. J. Kohel ◽  
T. S. Rangan ◽  
E. Commiskey
Keyword(s):  
Cell Culture ◽  
Tissue Culture ◽  
Somaclonal Variation ◽  
High Frequency ◽  
Chromosomal Abnormalities ◽  
Callus Cultures ◽  
Meiotic Abnormalities ◽  
High Frequencies ◽  
Field Environment ◽  
Metaphase I

Somaclonal variation occurs among regenerants from tissue culture of many plant species. Our objective was to determine whether cytogenetic variation contributes to somaclonal variation in cotton (Gossyptum hirsutum L.,2n = 4x = 52). Of 117 somaclones of cotton regenerated from 18-month-old callus cultures of 'SJ-2' and 'SJ-5' cultivars, 35 were analyzed for meiotic abnormalities. The population of somaclones was extremely varied in phenotype, most plants being strikingly aberrant in phenotype. Fertility was generally poor: 84% failed to set bolls and only 5% set 10 or more bolls in a field environment. Only one of the somaclones (3%) formed 26 bivalents at metaphase I. Fourteen were nonsynaptic to partially synaptic at metaphase I. Synaptic abnormalities impaired fertility and precluded thorough metaphase analysis. Chromosome numbers obtained for 32 plants ranged from 49 to 53, and only 1 plant was hyperaneuploid. No plant was polyploid. Chromosomal abnormalities in plants with normal metaphase pairing included univalents, unequal bivalents, rod bivalents, trivalents, open quadrivalents, and centric fragments. Seventeen hypoaneuploid plants formed a V-shaped trivalent at metaphase I, constituting a high frequency of tertiary monosomy. The high frequencies of aneuploidy and tertiary monosomy indicate that cytogenetic anomalies are a major source of somaclonal variation in cotton. It is hypothesized that (i) primary cytogenetic events during cotton cell culture give rise to breakage – fusion – bridge (BFB) cycles, (ii) BFB cycles accrue during culture, (iii) BFB cycles cause loss of chromatin, and (iv) BFB cycles are resolved by the formation of stable tertiary chromosomes with mono-centric activity. The hypothesis accounts mechanistically for the coincidence of chromatin deficiencies and chromatin exchange involved implicitly in tertiary monosomy, as well as for the relatively high frequency of tertiary monosomy among somaclones.Key words: aneuploid, monosomic, synaptic, sterility, Gossypium.

Relative stability among barley plants regenerated from cultured immature embryos

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 405-412 ◽  
Author(s):  
A. Karp ◽  
S. H. Steele ◽  
S. Parmar ◽  
M. G. K. Jones ◽  
P. R. Shewry ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Somaclonal Variation ◽  
Length Polymorphism ◽  
Immature Embryos ◽  
Glutamate Oxaloacetate Transaminase ◽  
Spacer Length ◽  
Factors Affecting ◽  
Regenerated Plants ◽  
Key Words Barley ◽  
Sds Page

Relative genetic stability was observed among barley plants regenerated from cultured immature embryos. Regenerated plants were studied cytologically and their seed progenies assayed for (i) the isoenzymes esterase and glutamate-oxaloacetate transaminase, (ii) ribosomal DNA spacer length polymorphism, and (iii) hordein patterns on SDS–PAGE. Of 42 regenerated plants, 1 regenerant had abnormal meiosis and the same plant produced one seed with a variant hordein pattern. These findings are discussed in relation to the factors affecting somaclonal variation in cereals and to methods of assaying the variation. Key words: barley, isozymes, somaclonal variation, tissue culture.

Chromosome 5D instability in cell lines of Triticum tauschii and morphological variation in regenerated plants

Genome ◽  
1995 ◽  
Vol 38 (4) ◽  
pp. 737-742 ◽  
Author(s):  
M. O. Winfield ◽  
A. Karp ◽  
P. A. Lazzeri ◽  
M. R. Davey
Keyword(s):  
Seed Set ◽  
Immature Embryo ◽  
Cell Suspensions ◽  
Chromosome Counts ◽  
Triticum Tauschii ◽  
Regenerated Plants ◽  
Immature Embryo Culture ◽  
Meiotic Analyses ◽  
L2 Medium ◽  
Indole 3 Acetic Acid

Immature embryos of Triticum tauschii cultured on L2 medium with 30 g∙L−1maltose gave rise to compact and highly structured callus that readily regenerated shoots when transferred to MS medium supplemented with zeatin and indole-3-acetic acid. Two cell suspensions were initiated from the callus induced on L2 medium. An analysis of chromosome number in these cell suspensions after 3 months of culture showed that 95 and 75% of the cells had a normal complement. After 5 months, in both lines the majority of cells had chromosome complements of 2n = 13 and many of these aneuploid cells possessed a dicentric chromosome. C-banding indicated that the dicentric was often formed from chromosomes 2D and 5D. Fifty-six plants regenerated from callus were grown to maturity. Variation was observed in tiller number, flowering time, and seed-set; in two cases, the variation in early flowering was shown to be heritable. All the regenerants analysed had normal chromosome counts (2n = 2x = 14) and meiotic analyses of 35 plants revealed no obvious structural rearrangements.Key words: immature embryo culture, regeneration, chromosome, cell suspension, Triticum tauschii.

Sign in / Sign up

Export Citation Format

Share Document