Wege zur züchterischen Nutzung desSolanum chacoense Bitt. in Hinblick auf die Züchtung käferresistenter Kartoffelsorten

Stelzner, G.

doi:10.1007/bf01812873

Cited by 12 publications

(1 citation statement)

References 3 publications

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“…In further sexual generations, quadruplex ps clones can arise . OPPENHEIMER (1933) and STELZNER (1943) both detected parallel spindles and dyads in interspecific hybrids between S. chacoense and German cultivars . The homozygous recessive condition allows for expression of the cha-racter as in a diploid ; FDR 2n pollen is formed by parallel spindles, but it contains 48 chromosomes .…”

Section: Resultsmentioning

confidence: 98%

2n gametes in potato species and their function in sexual polyploidization

1977

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The extent and pattern of polyploidy in the tuber-bearing Solanums varies among the many taxonomic series that have been identified in this subsection of Solanum . While several series appear to be entirely diploid, others exhibit a range of ploidy levels from 2x to 6x . and some contain only polyploid species .In many diploid . triploid and tetraploid species 2n gametes (gametes or gametophytes with the sporophytic chromosome number) have been detected . Both 2n eggs and 2n pollen occur . 2n gametes provide the opportunity for unilateral and bilateral sexual polyploidization . The genetic determination and consequences of sexual polyploidization strongly suggest that 2n gametes have been the major instrument in the polyploid evolution of the tuber-bearing Solanums . Somatic doubling of species and interspecific hybrids appears to be of very limited importance .New evidence for the occurrence of 2n eggs and 2n pollen in many species is reported, and data from the literature are added to illustrate the widespread distribution of 2n gametes throughout the subsection . A very high correlation is found between polyploidy and 2n gametes, and its significance is discussed . Proof is presented for the occurrence of alleles governing 2n pollen production in the cultivated tetraploids, providing additional evidence for the hypothesis that 2n gametes have been involved in their origin .Multiple unilateral and bilateral sexual polyploidizations are proposed for the origin of the cultivated tetraploids ; this accounts for the large variability encountered in this group, which closely resembles that of the related diploids . Similar evolutionary pathways are hypothesized for the other polyploid complexes in the subsection .A scheme is proposed in which participation of both 2n and n gametes link together all ploidy levels in the tuber-bearing Solanums, thus overcoming the ploidy barriers and providing for gene flow throughout the sympatric species of the subsection .

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Section: Resultsmentioning

confidence: 98%

2n gametes in potato species and their function in sexual polyploidization

1977

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Induced Tetraploid Solanum Species and Species Hybrids: Meiosis and Use in Breeding

Beamish

Cooper

Hougas

1957

American J of Botany

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The origin of unreduced microspores due to aberrant cytokinesis in the meiocytes of potato and its genetic significance

Ramanna

1974

Euphytica

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In 7 aneuhaploids of Solarium tuberosum and one clone of S. phureja the mechanism of unreduced microspore production has been studied. It has been observed that the unreduced microspores are produced not only by nuclear restitution at meiosis but also by aberrant cytokinesis in the meiocyte. The size and the number of nucleoli that are present in young microspores at the sporad stage give a fairly reliable indication of the ploidy level and the type of nuclear restitution that has occurred. These two aspects are helpful to deduce the meiotic events that have probably led to the formation of unreduced microspores in some cases. It has been found that triads and dyads are formed regardless of the type of nuclear division or restitution, indicating that cytokinesis is independent of karyokinesis to some extent. Cytological basis of unreduced microspore formation in diploid forms of potato appears to be more complex than it was supposed earlier.

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Wege zur züchterischen Nutzung desSolanum chacoense Bitt. in Hinblick auf die Züchtung käferresistenter Kartoffelsorten

Cited by 12 publications

References 3 publications

2n gametes in potato species and their function in sexual polyploidization

2n gametes in potato species and their function in sexual polyploidization

Induced Tetraploid Solanum Species and Species Hybrids: Meiosis and Use in Breeding

The origin of unreduced microspores due to aberrant cytokinesis in the meiocytes of potato and its genetic significance

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