Karyotype Analysis in<i>Triticum</i>: I — Analysis of<i>Triticum Turgidum</i>(L.) Thell. and Some Related Tetraploid Wheats

Giorgi, B.; Bozzini, A.

doi:10.1080/00087114.1969.10796344

Cited by 27 publications

(8 citation statements)

References 9 publications

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“…2) shows two satellited, two subterminal, three median, and seven pairs of submedian chromosomes. This karyotype is similar to that described for this species by Wagenaar (1966) and Giorgi and Bozzini (1969). The karotype of the timopheevilike mutant (Fig.…”

Section: Resultssupporting

confidence: 68%

“…It indicates structural-differentiation in five chromosome pairs of the mutant in relation to the karyotype of T. turgidum dicoccoides. While it is different from the karyotype obtained for T. timopheevi by Wagenaar ( 1966) and Scapova ( 1970) it is very close to that described for this species by Bozzini and Giorgi ( 1969) which showed similar chronloson~e structural changes, i.e., an increase in the number of median and subterminal chromosome pairs at the expense of submedian pairs. The timopheevi-like mutant indicates that chromosome structural modification relative to T. turgidum dic.occ.oides has occurred and supports Feldman's (1966) finding that the chromosomes of T. tirnophee~i differ from those of the A and B genomes of hexaploid wheat by at least five translocations.…”

Section: Resultssupporting

confidence: 47%

“…Although different from Sach's (1953) hypothesis of chromosome structural differentiation, Wagenaar (1961 ) suggested that the speciation of T. timophee~ii could have arisen through the action of desynaptic genes acting as an isolating barrier between it and T. turgidum. Evidence against the latter hypothesis can be found from (i) the T. turgidum -T. timopheevi amphidiploid (Sachs 1953;Bell and Sachs 1953) which were found to have regular chromosome pairing and high fertility; (ii) Feldman's (1966) evidence that pairing of most chromosomes of the A genome of T. aesti~um with T. tirnopheevi chromosomes is much higher than when B genome chromosomes are involved; (iii) Sears (1975) who showed that when a single T. tirnopheer~i chromosome was added to T. aestiljrrnl it paired only rarely with its homoeologue (6B) in the T. aesti1trrm background; (iv) the karyotype analyses for T. timopheel~i (Wagenaar 1966;Bozzini and Giorgi 1969;Scapova 1970) indicating chromosome structural divergence in this species in relation to T. turgidum dicoc.c-oides; (1,) studies of C banding and in situ hybridization (Hutchinson et al 1982) showing T. tirnopheevi to have translocation differences in relation to T. dicot-coides (between chromosomes of the respective genomes and between A and either B or G). The karyotype of the timophee1.i-like mutant and its meiotic chromosome pairing with T. tlrrgidum dicoc.c.oides reported in the present study were found to be consistent with an origin of chromosome structural differentiation.…”

Section: Discussionmentioning

confidence: 99%

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Evidence on the origin of the G genome in wheat: cytology and fertility of a T. timopheevi-like mutant

Kushnir¹,

Halloran²

1983

Can. J. Genet. Cytol.

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A spontaneous somatic mutant with Triticum timopheevi Zhuk. plant morphology was found in late tillers of a Triticum turgidum L. var. dicoccoides (Bowden) plant. Hybrids of the timopheevi-like mutant with T. turgidum L. var. dicocooides (Bowden), T. timopheevi Zhuk., and T. araraticum Jakubz. exhibited irregular pairing at meiosis and sterility, almost normal pairing and fertility, and relatively high pairing and sterility, respectively. This evidence plus that of karyotype changes in the somatic mutant indicated that it was differentiated from T. turgidum dicoccoides through chromosome interchanges. This mutation, believed to arise through chromosome rearrangement, is discussed in relation to the origin of the G genome of T. timopheevi.

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Section: Resultssupporting

confidence: 68%

Section: Resultssupporting

confidence: 47%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evidence on the origin of the G genome in wheat: cytology and fertility of a T. timopheevi-like mutant

Kushnir¹,

Halloran²

1983

Can. J. Genet. Cytol.

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“…V. pannonica, Crepis virens, C. sibirica, C. pulchra, Allium cepa, Aloe arborescens, Drosophyllum lusitanum, Hordeum vulgare, Makinoa crispata, Aneurapinguis corresponded to the number of secondary constrictions present in the respective complements. In hexaploid wheat, tetraploid wheat and hexaploid Triticale, the four large nucleoli in somatic cells are associated with two pairs of nucleolar chromosomes (Thomas & Kaltsikes, 1977;Darvey & Driscoll, 1972) which are those of tetraploid wheat (Giorgi & Bozzini, 1969) and among these, two have a stronger organizing capability than the other two (Crosby, 1957). Longwell & Svihla (1960) got clear evidence in 6x T. aestivum that the various nullisomic and polysomic combinations had a nucleolus number directly proportional to the number of nucleolar chromosomes present in the particular complement.…”

Section: Studies Of Male Meiosis In About 55 Species Ofmentioning

confidence: 90%

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

Verma

Raina

1981

Genetica

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Of 35 species of Crotalaria (Leguminosae) studied, all but one had usually one nucleolus in the premetaphase I cells. In C. agatiflora 300 PMCs from four out of five plants were investigated and the percentage cells with more than one nucleolus was determined as well as the nature of nucleolar attachment to bivalents and the range and the sizes of various nucleoli present in the cell. The "aberrant' cells ranged from 42 to 50%. The nucleoli (1-6) were usually attached to different bivalents. Where one nucleolus was present in the cell, it was always attached to an X-shaped bivalent, formed of a pair of nucleolar chromosomes. In the aberrant cells one nucleolus usually was attached to such a bivalent. The presence of accessory nucleoli has been attributed to hybridity as a result of large-scale intercrossing among five subspecies and consequent dispersal of intermediates in the adjoining areas where C. agatflora grows wild (East Africa and Ethiopia).The change in the regulatory system of the cell caused by hybridity results in activation of latent nucleolar organizers, although their overall presence in the genome is not due to hybridity.

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“…The nomenclature of LEVAN et al (1964) was followed to classify the centromeric position of the chromosomes as median (m) or submedian (sm). The results were compared with those reported by GIORGI and BOZZINI (1969) after adopting their arm-ratio values according to LEVAN et al (1964).…”

Section: Methodsmentioning

confidence: 99%

Cytogenetic Studies in Ethiopian Landraces of Tetraploid Wheat (Triticum Turgidum L.) I. Spike Morphology vs Ploidy Level and Karyomorphology

2004

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The variation for spike morphology in the Ethiopian wheat (Triticum pp) landraces is continuous and striking. For an inexperienced observer it is even difficult to distinguish their ploidy level (tetra– vs hexaploid) based only on morphological characteristics. The objectives of this study were to determine the concordance of spike morphology with ploidy level and to characterize the chromosomes of the tetraploids (2n = 4x =28) according to their centromeric positions so as to be able to detect any major deviation from the karyotype reported in the literature. Seventy‐four wheat landrace morphotypes collected from four localities in the central highlands of Ethiopia were used. Sixty‐nine morphotypes were tetraploid while five were hexaploid (2n = 6x =42), suggesting the need for chromosome number confirmation whenever there is a doubt. The Q‐factor complex, either introgressed from the hexaploids to the tetraploids or directly introduced as in T. carthlicum (2n = 4x = 28), seemed to have been responsible for the morphological overlapping. No aneuploidy was encountered. Genotypic differences in the resolution of nucleolus organizing regions were observed. The tetraploids, as a whole, had pairs of two satellited, eight median and four submedian chromosomes. The notable deviation detected was the fixed altered centromeric position of chromosome 6B in three morphotypes collected from three different localities. Unlike the ‘normal’ situation the satellite was attached to the longer arm. No connection was established between this rearrangement and the conspicuous variation for spike morphology or other useful agronomic traits including fertility. This may indicate a minor role for chromosomal rearrangement in either the morphological diversity or fitness characters of the wheat landraces Despite the presence of cytotypes, however, chromosome‐arm ratio remained highly stable after centuries of wheat cultivation in Ethiopia.

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Karyotype Analysis inTriticum: I — Analysis ofTriticum Turgidum(L.) Thell. and Some Related Tetraploid Wheats

Cited by 27 publications

References 9 publications

Evidence on the origin of the G genome in wheat: cytology and fertility of a T. timopheevi-like mutant

Evidence on the origin of the G genome in wheat: cytology and fertility of a T. timopheevi-like mutant

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

Cytogenetic Studies in Ethiopian Landraces of Tetraploid Wheat (Triticum Turgidum L.) I. Spike Morphology vs Ploidy Level and Karyomorphology

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