Cytogenetics and Reproductive Behavior of Different Chromosome Races in Six Paspalum Species

Norrmann, Guillermo Alberto; Quarín, Camilo Luis; Burson, Byron L.

doi:10.1093/oxfordjournals.jhered.a110783

Cited by 81 publications

(84 citation statements)

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“…The low frequency of quadrivalents in tetraploid accessions reported in several Paspalum species has been interpreted as resulting from segmental allopolyploidy (Burson and Bennett, 1971;Norrmann et al, 1989;Quarín et al, 1996;Takayama et al, 1998;Pagliarini et al, 2001). Although low multivalent frequency is an argument frequently used in advocating segmental allopolyploidy, Sybenga (1996a) pointed out that this character is not necessarily a reliable indication of limited pairing affinity, and thus of homology, because even true autopolyploids may form quadrivalents with frequencies substantially lower than theoretically possible.…”

Section: Resultsmentioning

confidence: 99%

Chromosome numbers and meiotic behavior of some Paspalum accessions

et al. 2005

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Chromosome number and meiotic behavior were evaluated in 36 Brazilian accessions of the grass Paspalum (which had never previously been analyzed) to determinate which accessions might be useful in interspecific hybridizations. The analysis showed that one accession of Paspalum coryphaeum was diploid (2n = 2x = 20) and one accession of Paspalum conspersum hexaploid (2n = 6x = 60), the remaining 34 accessions being tetraploid (2n = 4x = 40). The pairing configuration was typical for the ploidy level i.e. in the diploid, chromosomes paired as 10 bivalents, in tetraploids as bi-, tri-and quadrivalents, and in hexaploid as 30 bivalents. A low frequency of meiotic abnormalities (less than 10%) was observed in the diploid, hexaploid and some tetraploid accessions, although the majority of tetraploid accessions showed a high frequency of meiotic irregularities. The use of accessions with a low frequency of meiotic abnormalities in breeding programs is discussed.

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Section: Resultsmentioning

confidence: 99%

Chromosome numbers and meiotic behavior of some Paspalum accessions

et al. 2005

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“…On the other hand, breeders depend on a core collection, which must represent the natural variability of the species to be improved. The occurrence of apomixis and a wide range of ploidy levels make the knowledge on cytology and reproductive behavior of all available accessions an imperative issue for Paspalum improvement (NORRMANN et al, 1989). Routinely, crossing programs require knowing at least chromosome numbers and mode of reproduction of the potential parents.…”

Section: Introductionmentioning

confidence: 99%

Cytogenetic analyses in Paspalum L. reveal new diploid species and accessions

et al. 2008

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“…The meiotic behavior of diploid hybrids and natural polyploids suggests that several species in the Quadrifaria group, including P. quadrifarium, contain variable numbers of the more or less differentiated forms of the I genome (Norrmann et al, 1989;Quarín and Norrmann, 1990;Caponio and Quarín, 1992). Meiotic analyses of triploid (2n = 30) accessions of this species have led to different conclusions.…”

Section: Discussionmentioning

confidence: 99%

“…is native to Uruguay, central-eastern Argentina and the state of Rio Grande do Sul in Brazil (Quarín and Lombardo, 1986). Chromosome numbers reported for this species include 2n = 2x = 20 (Saura, 1941;Núñez, 1952;Quarín and Lombardo, 1986;Norrmann et al, 1989), 2n = 3x = 30 (Burton, 1942;Quarín and Lombardo, 1986;Norrmann et al, 1989), 2n = 4x = 40 (Burson and Bennett, 1970;Quarín and Lombardo, 1986;Norrmann et al, 1989), and 2n = 6x = 60 (Krishnaswamy, 1940). The cytogenetic architecture in this species has been inferred from meiotic behavior.…”

Section: Introductionmentioning

confidence: 99%

“…Several species of this group have been characterized from the reproductive and cytogenetic point of view. Norrmann et al (1989) analyzed P. intermedium Munro, P. haumanii Parodi, P. quadrifarium Lam., and P. brunneum Mez. All these species showed diploid and polyploid cytotypes, where the diploids were sexual and self-incompatible, and the polyploids were apomictic and showed multivalent associations in meiosis.…”

Section: Introductionmentioning

confidence: 99%

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Karyotypes of two cytotypes of Paspalum quadrifarium Lam. (Poaceae): an alternative technique for small chromosomes in plants

2003

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Paspalum quadrifarium Lam. is a bunchgrass native to Uruguay, Argentina, and southern Brazil. Diploid, triploid, tetraploid and hexaploid cytotypes have been reported for this species of the Quadrifaria group of Paspalum. In this group, a high degree of cytogenetic homology between the genomes of several diploid species has been reported, based on meiotic pairing in interspecific hybrids; multivalent associations would thus be expected in polyploid hybrids. Karyotype analysis could provide useful information about the genomic architecture of polyploid plants; however, the fully condensed mitotic chromosomes of Paspalum do not provide enough morphological features for such an analysis. In this paper, we used mitotic prometaphase chromosomes treated with 70% acetic acid at 40°C after cover slip removal. This process removes cytoplasm that remains from chromosome squashes and makes prometaphases available for karyological analysis. The karyotypes of a triploid (2n = 3x = 30) and a tetraploid (2n = 4x = 40) accession of Paspalum quadrifarium were studied using this technique, and evidence of segmental allopolyploidy was found in both cases. In both accessions, meiotic behavior was in accordance with that origin. This technique greatly improved the number and quality of analyzable metaphases and prometaphases on otherwise conventional slides and is recommended for plants with small chromosomes.

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Cytogenetics and Reproductive Behavior of Different Chromosome Races in Six Paspalum Species

Cited by 81 publications

References 0 publications

Chromosome numbers and meiotic behavior of some Paspalum accessions

Chromosome numbers and meiotic behavior of some Paspalum accessions

Cytogenetic analyses in Paspalum L. reveal new diploid species and accessions

Karyotypes of two cytotypes of Paspalum quadrifarium Lam. (Poaceae): an alternative technique for small chromosomes in plants

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