Meiotic associations at metaphase I in diploid, triploid, and tetraploid Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski.

Wang, Richard R.‐C.; Berdahl, J. D.

doi:10.1508/cytologia.55.639

Cited by 12 publications

(7 citation statements)

References 15 publications

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“…Tetraploid seeds were larger and produced robuster seedlings (Wang and Berdahl 1990). The example of tetraploid rye grass has been mentioned above: better palatibility is more important than higher production.…”

Section: Somatic Effectsmentioning

confidence: 95%

Cytogenetics in Plant Breeding

Sybenga

1992

Monographs on Theoretical and Applied Genetics

109

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Section: Somatic Effectsmentioning

confidence: 95%

Cytogenetics in Plant Breeding

Sybenga

1992

Monographs on Theoretical and Applied Genetics

109

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“…Kuspira et al 1985Kuspira et al 1986Santos et al 1995Moore 1963Moore 1963Mettin and Miiller 1970Santos et al 1995Swaminathan and Howard 1953Swaminathan and Howard 1953Lange and Wagenvoort 1973Lange and Wagenvoort 197 3 Srivastava et al 1992Srivastava et al 1992Tyagi and Dubey 1989Manga et al 198 1 Manga et al 1981Wang and Berdahl 1990Wang and Berdahl 1990Nakamura et al 1991Yu 1982, Nakamura et al 1991 Note bivalents are formed. In triploids, again 213 of the chromos'omes are involved in multivalents (trivalents) and the remainder are bivalents accompanied by a univalent.…”

Section: Segmental Allopolyploidmentioning

confidence: 99%

Chromosome pairing affinity and quadrivalent formation in polyploids: do segmental allopolyploids exist?

Sybenga¹

1996

Genome

119

120

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When polyploid hybrids with closely related genomes are propagated by selfing or sib-breeding, the meiotic behaviour will turn into essentially autopolyploid behaviour as soon as the affinity between the genomes is sufficient to permit occasional homoeologous pairing. An allopolyploid will only be formed when the initial differentiation is sufficient to completely prevent homoeologous pairing (in some cases enhanced by specific genes), or when segregational dysgenesis prevents transmission of recombined chromosomes. A new polyploid hybrid may be considered a segmental allopolyploid and may show reduced multivalent formation as a result of preferential pairing between the least differentiated genomes. An established polyploid is either an autopolyploid or an allopolyploid. In exceptional cases it is thinkable that a stable segmental allopolyploid arises, in which some sets of chromosomes are well differentiated and behave as in an allopolyploid, whereas other sets are not well differentiated and behave as in an autopolyploid. No clear cases have been found in the literature so far. Key words : chromosome, pairing affinity, quadrivalent frequency, segmental allopolyploidy.

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“…Vincent and Jones (1993), in autotriploid Scilla autumnalis, showed a trend where the longer chromosome sets had more pairing partner exchanges than the shorter chromosomes at prophase I. However, Wang and Berdahl (1990) when comparing Triticeae species found that trivalent frequency is not related to chromosome length. However, trivalent frequency is partly dependent on chiasma numbers (Thomas 1995).…”

mentioning

confidence: 99%

Meiosis in Triploid Lolium. IV. Distribution of Chiasmata in Autotriploids.

Thomas¹,

Morgan²,

Harper³

et al. 1997

CYTOLOGIA

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The frequency and distribution of chiasmata may vary between species, between genotypes, between cells and even between bivalents within cells, these differences may be due to genetic or environmental causes (Jones 1987). One restriction on the number of chiasmata per bivalent is chiasma interference. With very small bivalents this can limit the number of chiasmata to one. Excepting very small chromosomes, Mather (1937) showed that the number of chiasmata per bivalent was directly proportional to chromosome length.In six Lolium species, Rees and Narayan (1988) found a correlation between DNA amount and chiasma frequency. Vincent and Jones (1993), in autotriploid Scilla autumnalis, showed a trend where the longer chromosome sets had more pairing partner exchanges than the shorter chromosomes at prophase I. However, Wang and Berdahl (1990) when comparing Triticeae species found that trivalent frequency is not related to chromosome length. However, trivalent frequency is partly dependent on chiasma numbers (Thomas 1995).Analysis of synaptonemal complex formation in two aneuploid genotypes of autotriploid L. multiflorum revealed that 94% of homologous groups formed trivalents at prophase I. The trivalents had on average two pairing partner exchanges at pachytene and the two genotypes respectively had 3.1 and 2.7 chiasmata per homologous group at metaphase I. This was sufficient to ensure that in the two genotypes respectively, 88% and 86% of the trivalents formed during prophase I were retained to metaphase I. The rate of retention indicated that most of the chiasmata occurred in separate SC regions (Thomas and Thomas 1994). L. temulentum has 50% more DNA per nucleus than L. multiflorum and correspondingly longer chromosomes (Hutchinson et al. 1979) and a higher chiasma frequency at the diploid level (Rees and Narayan 1988). Thomas (1994) analyzed the frequencies of chiasmata, paired arms and chiasmata per paired arm in diploid L. multiflorum and L. temulentum. Chiasma frequency and chiasma distribution had separate control mechanisms so that a L. multiflorum genotype with a high chiasma frequency had a lower frequency of paired arms than a genotype of L. multiflorum with a low chiasma frequency. However, L. temulentum with its larger chromosomes, had a higher chiasma frequency and a higher frequency of paired arms than the L. multiflorum genotypes. The present report describes configurations at metaphase I and the distribution of chiasmata in autotriploid cytotypes of these two species. Materials and methodsDiploid and tetraploid cytotypes of L. multiflorum ssp. westerwoldicum Bb2074 and L. temulentum Ba3081 were crossed to produce the autotriploids. The autotriploids of L. multforum were produced by enclosing inflorescences of the diploid and tetraploid cytotypes in a pollination bag prior to anther dehiscence. Immature embryos were removed 18 days after pollination and cultured on a modified Gamborg B5 medium (Gamborg et al. 1968) with 3% sucrose but without 2, 4D and kinetin. The autotriploid L. temulentum was s...

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Meiotic associations at metaphase I in diploid, triploid, and tetraploid Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski.

Cited by 12 publications

References 15 publications

Cytogenetics in Plant Breeding

Cytogenetics in Plant Breeding

Chromosome pairing affinity and quadrivalent formation in polyploids: do segmental allopolyploids exist?

Meiosis in Triploid Lolium. IV. Distribution of Chiasmata in Autotriploids.

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